Currently we copy the whole mm_context_t to the paca but only access a
few bits of it. This is wasteful of space paca and also takes quite
some time in the hot path of context switching.
This patch pulls in only the required bits from the mm_context_t to
the paca and on context switch, copies only those.
Benchmarking this (On top of Anton's recent MSR context switching
changes [1]) using processes and yield shows an improvement of almost
3% on POWER8:
http://ozlabs.org/~anton/junkcode/context_switch2.c
./context_switch2 --test=yield --process 0 0
1. https://lists.ozlabs.org/pipermail/linuxppc-dev/2015-October/135700.html
Signed-off-by: Michael Neuling <mikey@neuling.org>
[mpe: Rename paca fields to be mm_ctx_foo rather than context_foo]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds a function to copy the mm->context to the paca. This is
only a basic conversion for now but will be used more extensively in
the next patch.
This also adds #ifdef CONFIG_PPC_BOOK3S around this code since it's
not used elsewhere.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This builds on the ability to run more than one vcore on a physical
core by using the micro-threading (split-core) modes of the POWER8
chip. Previously, only vcores from the same VM could be run together,
and (on POWER8) only if they had just one thread per core. With the
ability to split the core on guest entry and unsplit it on guest exit,
we can run up to 8 vcpu threads from up to 4 different VMs, and we can
run multiple vcores with 2 or 4 vcpus per vcore.
Dynamic micro-threading is only available if the static configuration
of the cores is whole-core mode (unsplit), and only on POWER8.
To manage this, we introduce a new kvm_split_mode struct which is
shared across all of the subcores in the core, with a pointer in the
paca on each thread. In addition we extend the core_info struct to
have information on each subcore. When deciding whether to add a
vcore to the set already on the core, we now have two possibilities:
(a) piggyback the vcore onto an existing subcore, or (b) start a new
subcore.
Currently, when any vcpu needs to exit the guest and switch to host
virtual mode, we interrupt all the threads in all subcores and switch
the core back to whole-core mode. It may be possible in future to
allow some of the subcores to keep executing in the guest while
subcore 0 switches to the host, but that is not implemented in this
patch.
This adds a module parameter called dynamic_mt_modes which controls
which micro-threading (split-core) modes the code will consider, as a
bitmap. In other words, if it is 0, no micro-threading mode is
considered; if it is 2, only 2-way micro-threading is considered; if
it is 4, only 4-way, and if it is 6, both 2-way and 4-way
micro-threading mode will be considered. The default is 6.
With this, we now have secondary threads which are the primary thread
for their subcore and therefore need to do the MMU switch. These
threads will need to be started even if they have no vcpu to run, so
we use the vcore pointer in the PACA rather than the vcpu pointer to
trigger them.
It is now possible for thread 0 to find that an exit has been
requested before it gets to switch the subcore state to the guest. In
that case we haven't added the guest's timebase offset to the
timebase, so we need to be careful not to subtract the offset in the
guest exit path. In fact we just skip the whole path that switches
back to host context, since we haven't switched to the guest context.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
When running a virtual core of a guest that is configured with fewer
threads per core than the physical cores have, the extra physical
threads are currently unused. This makes it possible to use them to
run one or more other virtual cores from the same guest when certain
conditions are met. This applies on POWER7, and on POWER8 to guests
with one thread per virtual core. (It doesn't apply to POWER8 guests
with multiple threads per vcore because they require a 1-1 virtual to
physical thread mapping in order to be able to use msgsndp and the
TIR.)
The idea is that we maintain a list of preempted vcores for each
physical cpu (i.e. each core, since the host runs single-threaded).
Then, when a vcore is about to run, it checks to see if there are
any vcores on the list for its physical cpu that could be
piggybacked onto this vcore's execution. If so, those additional
vcores are put into state VCORE_PIGGYBACK and their runnable VCPU
threads are started as well as the original vcore, which is called
the master vcore.
After the vcores have exited the guest, the extra ones are put back
onto the preempted list if any of their VCPUs are still runnable and
not idle.
This means that vcpu->arch.ptid is no longer necessarily the same as
the physical thread that the vcpu runs on. In order to make it easier
for code that wants to send an IPI to know which CPU to target, we
now store that in a new field in struct vcpu_arch, called thread_cpu.
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Since we moved the "lock" to be the first element of
struct tlb_core_data in commit 82d86de25b ("powerpc/e6500: Make TLB
lock recursive"), this macro is not used by any code. Just delete it.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
PACA_DSCR offset macro tracks dscr_default element in the paca
structure. Better change the name of this macro to match that of the
data element it tracks. Makes the code more readable.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This uses msgsnd where possible for signalling other threads within
the same core on POWER8 systems, rather than IPIs through the XICS
interrupt controller. This includes waking secondary threads to run
the guest, the interrupts generated by the virtual XICS, and the
interrupts to bring the other threads out of the guest when exiting.
Aggregated statistics from debugfs across vcpus for a guest with 32
vcpus, 8 threads/vcore, running on a POWER8, show this before the
change:
rm_entry: 3387.6ns (228 - 86600, 1008969 samples)
rm_exit: 4561.5ns (12 - 3477452, 1009402 samples)
rm_intr: 1660.0ns (12 - 553050, 3600051 samples)
and this after the change:
rm_entry: 3060.1ns (212 - 65138, 953873 samples)
rm_exit: 4244.1ns (12 - 9693408, 954331 samples)
rm_intr: 1342.3ns (12 - 1104718, 3405326 samples)
for a test of booting Fedora 20 big-endian to the login prompt.
The time taken for a H_PROD hcall (which is handled in the host
kernel) went down from about 35 microseconds to about 16 microseconds
with this change.
The noinline added to kvmppc_run_core turned out to be necessary for
good performance, at least with gcc 4.9.2 as packaged with Fedora 21
and a little-endian POWER8 host.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently, the entry_exit_count field in the kvmppc_vcore struct
contains two 8-bit counts, one of the threads that have started entering
the guest, and one of the threads that have started exiting the guest.
This changes it to an entry_exit_map field which contains two bitmaps
of 8 bits each. The advantage of doing this is that it gives us a
bitmap of which threads need to be signalled when exiting the guest.
That means that we no longer need to use the trick of setting the
HDEC to 0 to pull the other threads out of the guest, which led in
some cases to a spurious HDEC interrupt on the next guest entry.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
We can tell when a secondary thread has finished running a guest by
the fact that it clears its kvm_hstate.kvm_vcpu pointer, so there
is no real need for the nap_count field in the kvmppc_vcore struct.
This changes kvmppc_wait_for_nap to poll the kvm_hstate.kvm_vcpu
pointers of the secondary threads rather than polling vc->nap_count.
Besides reducing the size of the kvmppc_vcore struct by 8 bytes,
this also means that we can tell which secondary threads have got
stuck and thus print a more informative error message.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
* Remove unused kvmppc_vcore::n_busy field.
* Remove setting of RMOR, since it was only used on PPC970 and the
PPC970 KVM support has been removed.
* Don't use r1 or r2 in setting the runlatch since they are
conventionally reserved for other things; use r0 instead.
* Streamline the code a little and remove the ext_interrupt_to_host
label.
* Add some comments about register usage.
* hcall_try_real_mode doesn't need to be global, and can't be
called from C code anyway.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This reads the timebase at various points in the real-mode guest
entry/exit code and uses that to accumulate total, minimum and
maximum time spent in those parts of the code. Currently these
times are accumulated per vcpu in 5 parts of the code:
* rm_entry - time taken from the start of kvmppc_hv_entry() until
just before entering the guest.
* rm_intr - time from when we take a hypervisor interrupt in the
guest until we either re-enter the guest or decide to exit to the
host. This includes time spent handling hcalls in real mode.
* rm_exit - time from when we decide to exit the guest until the
return from kvmppc_hv_entry().
* guest - time spend in the guest
* cede - time spent napping in real mode due to an H_CEDE hcall
while other threads in the same vcore are active.
These times are exposed in debugfs in a directory per vcpu that
contains a file called "timings". This file contains one line for
each of the 5 timings above, with the name followed by a colon and
4 numbers, which are the count (number of times the code has been
executed), the total time, the minimum time, and the maximum time,
all in nanoseconds.
The overhead of the extra code amounts to about 30ns for an hcall that
is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since
production environments may not wish to incur this overhead, the new
code is conditional on a new config symbol,
CONFIG_KVM_BOOK3S_HV_EXIT_TIMING.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
We have two arrays in kvm_host_state that contain register values for
the PMU. Currently we only create an asm-offsets symbol for the base of
the arrays, and do the array offset in the assembly code.
Creating an asm-offsets symbol for each field individually makes the
code much nicer to read, particularly for the MMCRx/SIxR/SDAR fields, and
might have helped us notice the recent double restore bug we had in this
code.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Alexander Graf <agraf@suse.de>
The highlight is the series that reworks the idle management on powernv, which
allows us to use deeper idle states on those machines.
There's the fix from Anton for the "BUG at kernel/smpboot.c:134!" problem.
An i2c driver for powernv. This is acked by Wolfram Sang, and he asked that we
take it through the powerpc tree.
A fix for audit from rgb at Red Hat, acked by Paul Moore who is one of the audit
maintainers.
A patch from Ben to export the symbol map of our OPAL firmware as a sysfs file,
so that tools can use it.
Also some CXL fixes, a couple of powerpc perf fixes, a fix for smt-enabled, and
the patch to add __force to get_user() so we can use bitwise types.
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Merge tag 'powerpc-3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux
Pull second batch of powerpc updates from Michael Ellerman:
"The highlight is the series that reworks the idle management on
powernv, which allows us to use deeper idle states on those machines.
There's the fix from Anton for the "BUG at kernel/smpboot.c:134!"
problem.
An i2c driver for powernv. This is acked by Wolfram Sang, and he
asked that we take it through the powerpc tree.
A fix for audit from rgb at Red Hat, acked by Paul Moore who is one of
the audit maintainers.
A patch from Ben to export the symbol map of our OPAL firmware as a
sysfs file, so that tools can use it.
Also some CXL fixes, a couple of powerpc perf fixes, a fix for
smt-enabled, and the patch to add __force to get_user() so we can use
bitwise types"
* tag 'powerpc-3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
powerpc/powernv: Ignore smt-enabled on Power8 and later
powerpc/uaccess: Allow get_user() with bitwise types
powerpc/powernv: Expose OPAL firmware symbol map
powernv/powerpc: Add winkle support for offline cpus
powernv/cpuidle: Redesign idle states management
powerpc/powernv: Enable Offline CPUs to enter deep idle states
powerpc/powernv: Switch off MMU before entering nap/sleep/rvwinkle mode
i2c: Driver to expose PowerNV platform i2c busses
powerpc: add little endian flag to syscall_get_arch()
power/perf/hv-24x7: Use kmem_cache_free() instead of kfree
powerpc/perf/hv-24x7: Use per-cpu page buffer
cxl: Unmap MMIO regions when detaching a context
cxl: Add timeout to process element commands
cxl: Change contexts_lock to a mutex to fix sleep while atomic bug
powerpc: Secondary CPUs must set cpu_callin_map after setting active and online
- spring cleaning: removed support for IA64, and for hardware-assisted
virtualization on the PPC970
- ARM, PPC, s390 all had only small fixes
For x86:
- small performance improvements (though only on weird guests)
- usual round of hardware-compliancy fixes from Nadav
- APICv fixes
- XSAVES support for hosts and guests. XSAVES hosts were broken because
the (non-KVM) XSAVES patches inadvertently changed the KVM userspace
ABI whenever XSAVES was enabled; hence, this part is going to stable.
Guest support is just a matter of exposing the feature and CPUID leaves
support.
Right now KVM is broken for PPC BookE in your tree (doesn't compile).
I'll reply to the pull request with a patch, please apply it either
before the pull request or in the merge commit, in order to preserve
bisectability somewhat.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM update from Paolo Bonzini:
"3.19 changes for KVM:
- spring cleaning: removed support for IA64, and for hardware-
assisted virtualization on the PPC970
- ARM, PPC, s390 all had only small fixes
For x86:
- small performance improvements (though only on weird guests)
- usual round of hardware-compliancy fixes from Nadav
- APICv fixes
- XSAVES support for hosts and guests. XSAVES hosts were broken
because the (non-KVM) XSAVES patches inadvertently changed the KVM
userspace ABI whenever XSAVES was enabled; hence, this part is
going to stable. Guest support is just a matter of exposing the
feature and CPUID leaves support"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (179 commits)
KVM: move APIC types to arch/x86/
KVM: PPC: Book3S: Enable in-kernel XICS emulation by default
KVM: PPC: Book3S HV: Improve H_CONFER implementation
KVM: PPC: Book3S HV: Fix endianness of instruction obtained from HEIR register
KVM: PPC: Book3S HV: Remove code for PPC970 processors
KVM: PPC: Book3S HV: Tracepoints for KVM HV guest interactions
KVM: PPC: Book3S HV: Simplify locking around stolen time calculations
arch: powerpc: kvm: book3s_paired_singles.c: Remove unused function
arch: powerpc: kvm: book3s_pr.c: Remove unused function
arch: powerpc: kvm: book3s.c: Remove some unused functions
arch: powerpc: kvm: book3s_32_mmu.c: Remove unused function
KVM: PPC: Book3S HV: Check wait conditions before sleeping in kvmppc_vcore_blocked
KVM: PPC: Book3S HV: ptes are big endian
KVM: PPC: Book3S HV: Fix inaccuracies in ICP emulation for H_IPI
KVM: PPC: Book3S HV: Fix KSM memory corruption
KVM: PPC: Book3S HV: Fix an issue where guest is paused on receiving HMI
KVM: PPC: Book3S HV: Fix computation of tlbie operand
KVM: PPC: Book3S HV: Add missing HPTE unlock
KVM: PPC: BookE: Improve irq inject tracepoint
arm/arm64: KVM: Require in-kernel vgic for the arch timers
...
There are two ways in which a guest instruction can be obtained from
the guest in the guest exit code in book3s_hv_rmhandlers.S. If the
exit was caused by a Hypervisor Emulation interrupt (i.e. an illegal
instruction), the offending instruction is in the HEIR register
(Hypervisor Emulation Instruction Register). If the exit was caused
by a load or store to an emulated MMIO device, we load the instruction
from the guest by turning data relocation on and loading the instruction
with an lwz instruction.
Unfortunately, in the case where the guest has opposite endianness to
the host, these two methods give results of different endianness, but
both get put into vcpu->arch.last_inst. The HEIR value has been loaded
using guest endianness, whereas the lwz will load the instruction using
host endianness. The rest of the code that uses vcpu->arch.last_inst
assumes it was loaded using host endianness.
To fix this, we define a new vcpu field to store the HEIR value. Then,
in kvmppc_handle_exit_hv(), we transfer the value from this new field to
vcpu->arch.last_inst, doing a byte-swap if the guest and host endianness
differ.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This removes the code that was added to enable HV KVM to work
on PPC970 processors. The PPC970 is an old CPU that doesn't
support virtualizing guest memory. Removing PPC970 support also
lets us remove the code for allocating and managing contiguous
real-mode areas, the code for the !kvm->arch.using_mmu_notifiers
case, the code for pinning pages of guest memory when first
accessed and keeping track of which pages have been pinned, and
the code for handling H_ENTER hypercalls in virtual mode.
Book3S HV KVM is now supported only on POWER7 and POWER8 processors.
The KVM_CAP_PPC_RMA capability now always returns 0.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Winkle is a deep idle state supported in power8 chips. A core enters
winkle when all the threads of the core enter winkle. In this state
power supply to the entire chiplet i.e core, private L2 and private L3
is turned off. As a result it gives higher powersavings compared to
sleep.
But entering winkle results in a total hypervisor state loss. Hence the
hypervisor context has to be preserved before entering winkle and
restored upon wake up.
Power-on Reset Engine (PORE) is a dedicated engine which is responsible
for powering on the chiplet during wake up. It can be programmed to
restore the register contests of a few specific registers. This patch
uses PORE to restore register state wherever possible and uses stack to
save and restore rest of the necessary registers.
With hypervisor state restore things fall under three categories-
per-core state, per-subcore state and per-thread state. To manage this,
extend the infrastructure introduced for sleep. Mainly we add a paca
variable subcore_sibling_mask. Using this and the core_idle_state we can
distingush first thread in core and subcore.
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Deep idle states like sleep and winkle are per core idle states. A core
enters these states only when all the threads enter either the
particular idle state or a deeper one. There are tasks like fastsleep
hardware bug workaround and hypervisor core state save which have to be
done only by the last thread of the core entering deep idle state and
similarly tasks like timebase resync, hypervisor core register restore
that have to be done only by the first thread waking up from these
state.
The current idle state management does not have a way to distinguish the
first/last thread of the core waking/entering idle states. Tasks like
timebase resync are done for all the threads. This is not only is
suboptimal, but can cause functionality issues when subcores and kvm is
involved.
This patch adds the necessary infrastructure to track idle states of
threads in a per-core structure. It uses this info to perform tasks like
fastsleep workaround and timebase resync only once per core.
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Originally-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cleanup OpalMCE_* definitions/declarations and other related code which
is not used anymore.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Benjamin Herrrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
they had small conflicts (respectively within KVM documentation,
and with 3.16-rc changes). Since they were all within the subsystem,
I took care of them.
Stephen Rothwell reported some snags in PPC builds, but they are all
fixed now; the latest linux-next report was clean.
New features for ARM include:
- KVM VGIC v2 emulation on GICv3 hardware
- Big-Endian support for arm/arm64 (guest and host)
- Debug Architecture support for arm64 (arm32 is on Christoffer's todo list)
And for PPC:
- Book3S: Good number of LE host fixes, enable HV on LE
- Book3S HV: Add in-guest debug support
This release drops support for KVM on the PPC440. As a result, the
PPC merge removes more lines than it adds. :)
I also included an x86 change, since Davidlohr tied it to an independent
bug report and the reporter quickly provided a Tested-by; there was no
reason to wait for -rc2.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull second round of KVM changes from Paolo Bonzini:
"Here are the PPC and ARM changes for KVM, which I separated because
they had small conflicts (respectively within KVM documentation, and
with 3.16-rc changes). Since they were all within the subsystem, I
took care of them.
Stephen Rothwell reported some snags in PPC builds, but they are all
fixed now; the latest linux-next report was clean.
New features for ARM include:
- KVM VGIC v2 emulation on GICv3 hardware
- Big-Endian support for arm/arm64 (guest and host)
- Debug Architecture support for arm64 (arm32 is on Christoffer's todo list)
And for PPC:
- Book3S: Good number of LE host fixes, enable HV on LE
- Book3S HV: Add in-guest debug support
This release drops support for KVM on the PPC440. As a result, the
PPC merge removes more lines than it adds. :)
I also included an x86 change, since Davidlohr tied it to an
independent bug report and the reporter quickly provided a Tested-by;
there was no reason to wait for -rc2"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (122 commits)
KVM: Move more code under CONFIG_HAVE_KVM_IRQFD
KVM: nVMX: fix "acknowledge interrupt on exit" when APICv is in use
KVM: nVMX: Fix nested vmexit ack intr before load vmcs01
KVM: PPC: Enable IRQFD support for the XICS interrupt controller
KVM: Give IRQFD its own separate enabling Kconfig option
KVM: Move irq notifier implementation into eventfd.c
KVM: Move all accesses to kvm::irq_routing into irqchip.c
KVM: irqchip: Provide and use accessors for irq routing table
KVM: Don't keep reference to irq routing table in irqfd struct
KVM: PPC: drop duplicate tracepoint
arm64: KVM: fix 64bit CP15 VM access for 32bit guests
KVM: arm64: GICv3: mandate page-aligned GICV region
arm64: KVM: GICv3: move system register access to msr_s/mrs_s
KVM: PPC: PR: Handle FSCR feature deselects
KVM: PPC: HV: Remove generic instruction emulation
KVM: PPC: BOOKEHV: rename e500hv_spr to bookehv_spr
KVM: PPC: Remove DCR handling
KVM: PPC: Expose helper functions for data/inst faults
KVM: PPC: Separate loadstore emulation from priv emulation
KVM: PPC: Handle magic page in kvmppc_ld/st
...
SPRN_SPRG is used by debug interrupt handler, so this is required for
debug support.
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This provides a way for userspace controls which sPAPR hcalls get
handled in the kernel. Each hcall can be individually enabled or
disabled for in-kernel handling, except for H_RTAS. The exception
for H_RTAS is because userspace can already control whether
individual RTAS functions are handled in-kernel or not via the
KVM_PPC_RTAS_DEFINE_TOKEN ioctl, and because the numeric value for
H_RTAS is out of the normal sequence of hcall numbers.
Hcalls are enabled or disabled using the KVM_ENABLE_CAP ioctl for the
KVM_CAP_PPC_ENABLE_HCALL capability on the file descriptor for the VM.
The args field of the struct kvm_enable_cap specifies the hcall number
in args[0] and the enable/disable flag in args[1]; 0 means disable
in-kernel handling (so that the hcall will always cause an exit to
userspace) and 1 means enable. Enabling or disabling in-kernel
handling of an hcall is effective across the whole VM.
The ability for KVM_ENABLE_CAP to be used on a VM file descriptor
on PowerPC is new, added by this commit. The KVM_CAP_ENABLE_CAP_VM
capability advertises that this ability exists.
When a VM is created, an initial set of hcalls are enabled for
in-kernel handling. The set that is enabled is the set that have
an in-kernel implementation at this point. Any new hcall
implementations from this point onwards should not be added to the
default set without a good reason.
No distinction is made between real-mode and virtual-mode hcall
implementations; the one setting controls them both.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Old cpus didn't have a Segment Lookaside Buffer (SLB), instead they had
a Segment Table (STAB). Now that we've dropped support for those cpus,
we can remove the STAB support entirely.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull powerpc updates from Ben Herrenschmidt:
"Here is the bulk of the powerpc changes for this merge window. It got
a bit delayed in part because I wasn't paying attention, and in part
because I discovered I had a core PCI change without a PCI maintainer
ack in it. Bjorn eventually agreed it was ok to merge it though we'll
probably improve it later and I didn't want to rebase to add his ack.
There is going to be a bit more next week, essentially fixes that I
still want to sort through and test.
The biggest item this time is the support to build the ppc64 LE kernel
with our new v2 ABI. We previously supported v2 userspace but the
kernel itself was a tougher nut to crack. This is now sorted mostly
thanks to Anton and Rusty.
We also have a fairly big series from Cedric that add support for
64-bit LE zImage boot wrapper. This was made harder by the fact that
traditionally our zImage wrapper was always 32-bit, but our new LE
toolchains don't really support 32-bit anymore (it's somewhat there
but not really "supported") so we didn't want to rely on it. This
meant more churn that just endian fixes.
This brings some more LE bits as well, such as the ability to run in
LE mode without a hypervisor (ie. under OPAL firmware) by doing the
right OPAL call to reinitialize the CPU to take HV interrupts in the
right mode and the usual pile of endian fixes.
There's another series from Gavin adding EEH improvements (one day we
*will* have a release with less than 20 EEH patches, I promise!).
Another highlight is the support for the "Split core" functionality on
P8 by Michael. This allows a P8 core to be split into "sub cores" of
4 threads which allows the subcores to run different guests under KVM
(the HW still doesn't support a partition per thread).
And then the usual misc bits and fixes ..."
[ Further delayed by gmail deciding that BenH is a dirty spammer.
Google knows. ]
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (155 commits)
powerpc/powernv: Add missing include to LPC code
selftests/powerpc: Test the THP bug we fixed in the previous commit
powerpc/mm: Check paca psize is up to date for huge mappings
powerpc/powernv: Pass buffer size to OPAL validate flash call
powerpc/pseries: hcall functions are exported to modules, need _GLOBAL_TOC()
powerpc: Exported functions __clear_user and copy_page use r2 so need _GLOBAL_TOC()
powerpc/powernv: Set memory_block_size_bytes to 256MB
powerpc: Allow ppc_md platform hook to override memory_block_size_bytes
powerpc/powernv: Fix endian issues in memory error handling code
powerpc/eeh: Skip eeh sysfs when eeh is disabled
powerpc: 64bit sendfile is capped at 2GB
powerpc/powernv: Provide debugfs access to the LPC bus via OPAL
powerpc/serial: Use saner flags when creating legacy ports
powerpc: Add cpu family documentation
powerpc/xmon: Fix up xmon format strings
powerpc/powernv: Add calls to support little endian host
powerpc: Document sysfs DSCR interface
powerpc: Fix regression of per-CPU DSCR setting
powerpc: Split __SYSFS_SPRSETUP macro
arch: powerpc/fadump: Cleaning up inconsistent NULL checks
...
POWER8 implements a new register called TAR. This register has to be
enabled in FSCR and then from KVM's point of view is mere storage.
This patch enables the guest to use TAR.
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 introduced a new interrupt type called "Facility unavailable interrupt"
which contains its status message in a new register called FSCR.
Handle these exits and try to emulate instructions for unhandled facilities.
Follow-on patches enable KVM to expose specific facilities into the guest.
Signed-off-by: Alexander Graf <agraf@suse.de>
The shared (magic) page is a data structure that contains often used
supervisor privileged SPRs accessible via memory to the user to reduce
the number of exits we have to take to read/write them.
When we actually share this structure with the guest we have to maintain
it in guest endianness, because some of the patch tricks only work with
native endian load/store operations.
Since we only share the structure with either host or guest in little
endian on book3s_64 pr mode, we don't have to worry about booke or book3s hv.
For booke, the shared struct stays big endian. For book3s_64 hv we maintain
the struct in host native endian, since it never gets shared with the guest.
For book3s_64 pr we introduce a variable that tells us which endianness the
shared struct is in and route every access to it through helper inline
functions that evaluate this variable.
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch make sure we inherit the LE bit correctly in different case
so that we can run Little Endian distro in PR mode
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Since commit "efcac65 powerpc: Per process DSCR + some fixes (try#4)"
it is no longer possible to set the DSCR on a per-CPU basis.
The old behaviour was to minipulate the DSCR SPR directly but this is no
longer sufficient: the value is quickly overwritten by context switching.
This patch stores the per-CPU DSCR value in a kernel variable rather than
directly in the SPR and it is used whenever a process has not set the DSCR
itself. The sysfs interface (/sys/devices/system/cpu/cpuN/dscr) is unchanged.
Writes to the old global default (/sys/devices/system/cpu/dscr_default)
now set all of the per-CPU values and reads return the last written value.
The new per-CPU default is added to the paca_struct and is used everywhere
outside of sysfs.c instead of the old global default.
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Previously SPRG3 was marked for use by both VDSO and critical
interrupts (though critical interrupts were not fully implemented).
In commit 8b64a9dfb0 ("powerpc/booke64:
Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman
made an attempt to resolve this conflict by restoring the VDSO value
early in the critical interrupt, but this has some issues:
- It's incompatible with EXCEPTION_COMMON which restores r13 from the
by-then-overwritten scratch (this cost me some debugging time).
- It forces critical exceptions to be a special case handled
differently from even machine check and debug level exceptions.
- It didn't occur to me that it was possible to make this work at all
(by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after
I made (most of) this patch. :-)
It might be worth investigating using a load rather than SPRG on return
from all exceptions (except TLB misses where the scratch never leaves
the SPRG) -- it could save a few cycles. Until then, let's stick with
SPRG for all exceptions.
Since we cannot use SPRG4-7 for scratch without corrupting the state of
a KVM guest, move VDSO to SPRG7 on book3e. Since neither SPRG4-7 nor
critical interrupts exist on book3s, SPRG3 is still used for VDSO
there.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: kvm-ppc@vger.kernel.org
two s390 guest features that need some handling in the host,
and all the PPC changes. The PPC changes include support for
little-endian guests and enablement for new POWER8 features.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull more KVM updates from Paolo Bonzini:
"Second batch of KVM updates. Some minor x86 fixes, two s390 guest
features that need some handling in the host, and all the PPC changes.
The PPC changes include support for little-endian guests and
enablement for new POWER8 features"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (45 commits)
x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101
x86, kvm: cache the base of the KVM cpuid leaves
kvm: x86: move KVM_CAP_HYPERV_TIME outside #ifdef
KVM: PPC: Book3S PR: Cope with doorbell interrupts
KVM: PPC: Book3S HV: Add software abort codes for transactional memory
KVM: PPC: Book3S HV: Add new state for transactional memory
powerpc/Kconfig: Make TM select VSX and VMX
KVM: PPC: Book3S HV: Basic little-endian guest support
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7
KVM: PPC: Book3S HV: Prepare for host using hypervisor doorbells
KVM: PPC: Book3S HV: Handle new LPCR bits on POWER8
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap
KVM: PPC: Book3S HV: Implement architecture compatibility modes for POWER8
KVM: PPC: Book3S HV: Add handler for HV facility unavailable
KVM: PPC: Book3S HV: Flush the correct number of TLB sets on POWER8
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers
KVM: PPC: Book3S HV: Don't set DABR on POWER8
kvm/ppc: IRQ disabling cleanup
...
Pull powerpc updates from Ben Herrenschmidt:
"So here's my next branch for powerpc. A bit late as I was on vacation
last week. It's mostly the same stuff that was in next already, I
just added two patches today which are the wiring up of lockref for
powerpc, which for some reason fell through the cracks last time and
is trivial.
The highlights are, in addition to a bunch of bug fixes:
- Reworked Machine Check handling on kernels running without a
hypervisor (or acting as a hypervisor). Provides hooks to handle
some errors in real mode such as TLB errors, handle SLB errors,
etc...
- Support for retrieving memory error information from the service
processor on IBM servers running without a hypervisor and routing
them to the memory poison infrastructure.
- _PAGE_NUMA support on server processors
- 32-bit BookE relocatable kernel support
- FSL e6500 hardware tablewalk support
- A bunch of new/revived board support
- FSL e6500 deeper idle states and altivec powerdown support
You'll notice a generic mm change here, it has been acked by the
relevant authorities and is a pre-req for our _PAGE_NUMA support"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (121 commits)
powerpc: Implement arch_spin_is_locked() using arch_spin_value_unlocked()
powerpc: Add support for the optimised lockref implementation
powerpc/powernv: Call OPAL sync before kexec'ing
powerpc/eeh: Escalate error on non-existing PE
powerpc/eeh: Handle multiple EEH errors
powerpc: Fix transactional FP/VMX/VSX unavailable handlers
powerpc: Don't corrupt transactional state when using FP/VMX in kernel
powerpc: Reclaim two unused thread_info flag bits
powerpc: Fix races with irq_work
Move precessing of MCE queued event out from syscall exit path.
pseries/cpuidle: Remove redundant call to ppc64_runlatch_off() in cpu idle routines
powerpc: Make add_system_ram_resources() __init
powerpc: add SATA_MV to ppc64_defconfig
powerpc/powernv: Increase candidate fw image size
powerpc: Add debug checks to catch invalid cpu-to-node mappings
powerpc: Fix the setup of CPU-to-Node mappings during CPU online
powerpc/iommu: Don't detach device without IOMMU group
powerpc/eeh: Hotplug improvement
powerpc/eeh: Call opal_pci_reinit() on powernv for restoring config space
powerpc/eeh: Add restore_config operation
...
Add new state for transactional memory (TM) to kvm_vcpu_arch. Also add
asm-offset bits that are going to be required.
This also moves the existing TFHAR, TFIAR and TEXASR SPRs into a
CONFIG_PPC_TRANSACTIONAL_MEM section. This requires some code changes to
ensure we still compile with CONFIG_PPC_TRANSACTIONAL_MEM=N. Much of the added
the added #ifdefs are removed in a later patch when the bulk of the TM code is
added.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix merge conflict]
Signed-off-by: Alexander Graf <agraf@suse.de>
We create a guest MSR from scratch when delivering exceptions in
a few places. Instead of extracting LPCR[ILE] and inserting it
into MSR_LE each time, we simply create a new variable intr_msr which
contains the entire MSR to use. For a little-endian guest, userspace
needs to set the ILE (interrupt little-endian) bit in the LPCR for
each vcpu (or at least one vcpu in each virtual core).
[paulus@samba.org - removed H_SET_MODE implementation from original
version of the patch, and made kvmppc_set_lpcr update vcpu->arch.intr_msr.]
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
The DABRX (DABR extension) register on POWER7 processors provides finer
control over which accesses cause a data breakpoint interrupt. It
contains 3 bits which indicate whether to enable accesses in user,
kernel and hypervisor modes respectively to cause data breakpoint
interrupts, plus one bit that enables both real mode and virtual mode
accesses to cause interrupts. Currently, KVM sets DABRX to allow
both kernel and user accesses to cause interrupts while in the guest.
This adds support for the guest to specify other values for DABRX.
PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR
and DABRX with one call. This adds a real-mode implementation of
H_SET_XDABR, which shares most of its code with the existing H_SET_DABR
implementation. To support this, we add a per-vcpu field to store the
DABRX value plus code to get and set it via the ONE_REG interface.
For Linux guests to use this new hcall, userspace needs to add
"hcall-xdabr" to the set of strings in the /chosen/hypertas-functions
property in the device tree. If userspace does this and then migrates
the guest to a host where the kernel doesn't include this patch, then
userspace will need to implement H_SET_XDABR by writing the specified
DABR value to the DABR using the ONE_REG interface. In that case, the
old kernel will set DABRX to DABRX_USER | DABRX_KERNEL. That should
still work correctly, at least for Linux guests, since Linux guests
cope with getting data breakpoint interrupts in modes that weren't
requested by just ignoring the interrupt, and Linux guests never set
DABRX_BTI.
The other thing this does is to make H_SET_DABR and H_SET_XDABR work
on POWER8, which has the DAWR and DAWRX instead of DABR/X. Guests that
know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but
guests running in POWER7 compatibility mode will still use H_SET_[X]DABR.
For them, this adds the logic to convert DABR/X values into DAWR/X values
on POWER8.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds fields to the struct kvm_vcpu_arch to store the new
guest-accessible SPRs on POWER8, adds code to the get/set_one_reg
functions to allow userspace to access this state, and adds code to
the guest entry and exit to context-switch these SPRs between host
and guest.
Note that DPDES (Directed Privileged Doorbell Exception State) is
shared between threads on a core; hence we store it in struct
kvmppc_vcore and have the master thread save and restore it.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
On a threaded processor such as POWER7, we group VCPUs into virtual
cores and arrange that the VCPUs in a virtual core run on the same
physical core. Currently we don't enforce any correspondence between
virtual thread numbers within a virtual core and physical thread
numbers. Physical threads are allocated starting at 0 on a first-come
first-served basis to runnable virtual threads (VCPUs).
POWER8 implements a new "msgsndp" instruction which guest kernels can
use to interrupt other threads in the same core or sub-core. Since
the instruction takes the destination physical thread ID as a parameter,
it becomes necessary to align the physical thread IDs with the virtual
thread IDs, that is, to make sure virtual thread N within a virtual
core always runs on physical thread N.
This means that it's possible that thread 0, which is where we call
__kvmppc_vcore_entry, may end up running some other vcpu than the
one whose task called kvmppc_run_core(), or it may end up running
no vcpu at all, if for example thread 0 of the virtual core is
currently executing in userspace. However, we do need thread 0
to be responsible for switching the MMU -- a previous version of
this patch that had other threads switching the MMU was found to
be responsible for occasional memory corruption and machine check
interrupts in the guest on POWER7 machines.
To accommodate this, we no longer pass the vcpu pointer to
__kvmppc_vcore_entry, but instead let the assembly code load it from
the PACA. Since the assembly code will need to know the kvm pointer
and the thread ID for threads which don't have a vcpu, we move the
thread ID into the PACA and we add a kvm pointer to the virtual core
structure.
In the case where thread 0 has no vcpu to run, it still calls into
kvmppc_hv_entry in order to do the MMU switch, and then naps until
either its vcpu is ready to run in the guest, or some other thread
needs to exit the guest. In the latter case, thread 0 jumps to the
code that switches the MMU back to the host. This control flow means
that now we switch the MMU before loading any guest vcpu state.
Similarly, on guest exit we now save all the guest vcpu state before
switching the MMU back to the host. This has required substantial
code movement, making the diff rather large.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
There are a few things that make the existing hw tablewalk handlers
unsuitable for e6500:
- Indirect entries go in TLB1 (though the resulting direct entries go in
TLB0).
- It has threads, but no "tlbsrx." -- so we need a spinlock and
a normal "tlbsx". Because we need this lock, hardware tablewalk
is mandatory on e6500 unless we want to add spinlock+tlbsx to
the normal bolted TLB miss handler.
- TLB1 has no HES (nor next-victim hint) so we need software round robin
(TODO: integrate this round robin data with hugetlb/KVM)
- The existing tablewalk handlers map half of a page table at a time,
because IBM hardware has a fixed 1MiB indirect page size. e6500
has variable size indirect entries, with a minimum of 2MiB.
So we can't do the half-page indirect mapping, and even if we
could it would be less efficient than mapping the full page.
- Like on e5500, the linear mapping is bolted, so we don't need the
overhead of supporting nested tlb misses.
Note that hardware tablewalk does not work in rev1 of e6500.
We do not expect to support e6500 rev1 in mainline Linux.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic
FP/VSX and VMX load/store functions instead of open-coding the
FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't
follow C calling conventions, we make them private symbols within
book3s_hv_rmhandlers.S.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This uses struct thread_fp_state and struct thread_vr_state to store
the floating-point, VMX/Altivec and VSX state, rather than flat arrays.
This makes transferring the state to/from the thread_struct simpler
and allows us to unify the get/set_one_reg implementations for the
VSX registers.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
We don't use PACATOC for PR. Avoid updating HOST_R2 with PR
KVM mode when both HV and PR are enabled in the kernel. Without this we
get the below crash
(qemu)
Unable to handle kernel paging request for data at address 0xffffffffffff8310
Faulting instruction address: 0xc00000000001d5a4
cpu 0x2: Vector: 300 (Data Access) at [c0000001dc53aef0]
pc: c00000000001d5a4: .vtime_delta.isra.1+0x34/0x1d0
lr: c00000000001d760: .vtime_account_system+0x20/0x60
sp: c0000001dc53b170
msr: 8000000000009032
dar: ffffffffffff8310
dsisr: 40000000
current = 0xc0000001d76c62d0
paca = 0xc00000000fef1100 softe: 0 irq_happened: 0x01
pid = 4472, comm = qemu-system-ppc
enter ? for help
[c0000001dc53b200] c00000000001d760 .vtime_account_system+0x20/0x60
[c0000001dc53b290] c00000000008d050 .kvmppc_handle_exit_pr+0x60/0xa50
[c0000001dc53b340] c00000000008f51c kvm_start_lightweight+0xb4/0xc4
[c0000001dc53b510] c00000000008cdf0 .kvmppc_vcpu_run_pr+0x150/0x2e0
[c0000001dc53b9e0] c00000000008341c .kvmppc_vcpu_run+0x2c/0x40
[c0000001dc53ba50] c000000000080af4 .kvm_arch_vcpu_ioctl_run+0x54/0x1b0
[c0000001dc53bae0] c00000000007b4c8 .kvm_vcpu_ioctl+0x478/0x730
[c0000001dc53bca0] c0000000002140cc .do_vfs_ioctl+0x4ac/0x770
[c0000001dc53bd80] c0000000002143e8 .SyS_ioctl+0x58/0xb0
[c0000001dc53be30] c000000000009e58 syscall_exit+0x0/0x98
Signed-off-by: Alexander Graf <agraf@suse.de>
Move machine check entry point into Linux. So far we were dependent on
firmware to decode MCE error details and handover the high level info to OS.
This patch introduces early machine check routine that saves the MCE
information (srr1, srr0, dar and dsisr) to the emergency stack. We allocate
stack frame on emergency stack and set the r1 accordingly. This allows us to be
prepared to take another exception without loosing context. One thing to note
here that, if we get another machine check while ME bit is off then we risk a
checkstop. Hence we restrict ourselves to save only MCE information and
register saved on PACA_EXMC save are before we turn the ME bit on. We use
paca->in_mce flag to differentiate between first entry and nested machine check
entry which helps proper use of emergency stack. We increment paca->in_mce
every time we enter in early machine check handler and decrement it while
leaving. When we enter machine check early handler first time (paca->in_mce ==
0), we are sure nobody is using MC emergency stack and allocate a stack frame
at the start of the emergency stack. During subsequent entry (paca->in_mce >
0), we know that r1 points inside emergency stack and we allocate separate
stack frame accordingly. This prevents us from clobbering MCE information
during nested machine checks.
The early machine check handler changes are placed under CPU_FTR_HVMODE
section. This makes sure that the early machine check handler will get executed
only in hypervisor kernel.
This is the code flow:
Machine Check Interrupt
|
V
0x200 vector ME=0, IR=0, DR=0
|
V
+-----------------------------------------------+
|machine_check_pSeries_early: | ME=0, IR=0, DR=0
| Alloc frame on emergency stack |
| Save srr1, srr0, dar and dsisr on stack |
+-----------------------------------------------+
|
(ME=1, IR=0, DR=0, RFID)
|
V
machine_check_handle_early ME=1, IR=0, DR=0
|
V
+-----------------------------------------------+
| machine_check_early (r3=pt_regs) | ME=1, IR=0, DR=0
| Things to do: (in next patches) |
| Flush SLB for SLB errors |
| Flush TLB for TLB errors |
| Decode and save MCE info |
+-----------------------------------------------+
|
(Fall through existing exception handler routine.)
|
V
machine_check_pSerie ME=1, IR=0, DR=0
|
(ME=1, IR=1, DR=1, RFID)
|
V
machine_check_common ME=1, IR=1, DR=1
.
.
.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
side: the HV and emulation flavors can now coexist in a single kernel
is probably the most interesting change from a user point of view.
On the x86 side there are nested virtualization improvements and a
few bugfixes. ARM got transparent huge page support, improved
overcommit, and support for big endian guests.
Finally, there is a new interface to connect KVM with VFIO. This
helps with devices that use NoSnoop PCI transactions, letting the
driver in the guest execute WBINVD instructions. This includes
some nVidia cards on Windows, that fail to start without these
patches and the corresponding userspace changes.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM changes from Paolo Bonzini:
"Here are the 3.13 KVM changes. There was a lot of work on the PPC
side: the HV and emulation flavors can now coexist in a single kernel
is probably the most interesting change from a user point of view.
On the x86 side there are nested virtualization improvements and a few
bugfixes.
ARM got transparent huge page support, improved overcommit, and
support for big endian guests.
Finally, there is a new interface to connect KVM with VFIO. This
helps with devices that use NoSnoop PCI transactions, letting the
driver in the guest execute WBINVD instructions. This includes some
nVidia cards on Windows, that fail to start without these patches and
the corresponding userspace changes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (146 commits)
kvm, vmx: Fix lazy FPU on nested guest
arm/arm64: KVM: PSCI: propagate caller endianness to the incoming vcpu
arm/arm64: KVM: MMIO support for BE guest
kvm, cpuid: Fix sparse warning
kvm: Delete prototype for non-existent function kvm_check_iopl
kvm: Delete prototype for non-existent function complete_pio
hung_task: add method to reset detector
pvclock: detect watchdog reset at pvclock read
kvm: optimize out smp_mb after srcu_read_unlock
srcu: API for barrier after srcu read unlock
KVM: remove vm mmap method
KVM: IOMMU: hva align mapping page size
KVM: x86: trace cpuid emulation when called from emulator
KVM: emulator: cleanup decode_register_operand() a bit
KVM: emulator: check rex prefix inside decode_register()
KVM: x86: fix emulation of "movzbl %bpl, %eax"
kvm_host: typo fix
KVM: x86: emulate SAHF instruction
MAINTAINERS: add tree for kvm.git
Documentation/kvm: add a 00-INDEX file
...
This way we can use same data type struct with KVM and
also help in using other debug related function.
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Acked-by: Michael Neuling <mikey@neuling.org>
[scottwood@freescale.com: removed obvious debug_reg comment]
Signed-off-by: Scott Wood <scottwood@freescale.com>
This help ups to select the relevant code in the kernel code
when we later move HV and PR bits as seperate modules. The patch
also makes the config options for PR KVM selectable
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
With later patches supporting PR kvm as a kernel module, the changes
that has to be built into the main kernel binary to enable PR KVM module
is now selected via KVM_BOOK3S_PR_POSSIBLE
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This way we can use same data type struct with KVM and
also help in using other debug related function.
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently PR-style KVM keeps the volatile guest register values
(R0 - R13, CR, LR, CTR, XER, PC) in a shadow_vcpu struct rather than
the main kvm_vcpu struct. For 64-bit, the shadow_vcpu exists in two
places, a kmalloc'd struct and in the PACA, and it gets copied back
and forth in kvmppc_core_vcpu_load/put(), because the real-mode code
can't rely on being able to access the kmalloc'd struct.
This changes the code to copy the volatile values into the shadow_vcpu
as one of the last things done before entering the guest. Similarly
the values are copied back out of the shadow_vcpu to the kvm_vcpu
immediately after exiting the guest. We arrange for interrupts to be
still disabled at this point so that we can't get preempted on 64-bit
and end up copying values from the wrong PACA.
This means that the accessor functions in kvm_book3s.h for these
registers are greatly simplified, and are same between PR and HV KVM.
In places where accesses to shadow_vcpu fields are now replaced by
accesses to the kvm_vcpu, we can also remove the svcpu_get/put pairs.
Finally, on 64-bit, we don't need the kmalloc'd struct at all any more.
With this, the time to read the PVR one million times in a loop went
from 567.7ms to 575.5ms (averages of 6 values), an increase of about
1.4% for this worse-case test for guest entries and exits. The
standard deviation of the measurements is about 11ms, so the
difference is only marginally significant statistically.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This enables us to use the Processor Compatibility Register (PCR) on
POWER7 to put the processor into architecture 2.05 compatibility mode
when running a guest. In this mode the new instructions and registers
that were introduced on POWER7 are disabled in user mode. This
includes all the VSX facilities plus several other instructions such
as ldbrx, stdbrx, popcntw, popcntd, etc.
To select this mode, we have a new register accessible through the
set/get_one_reg interface, called KVM_REG_PPC_ARCH_COMPAT. Setting
this to zero gives the full set of capabilities of the processor.
Setting it to one of the "logical" PVR values defined in PAPR puts
the vcpu into the compatibility mode for the corresponding
architecture level. The supported values are:
0x0f000002 Architecture 2.05 (POWER6)
0x0f000003 Architecture 2.06 (POWER7)
0x0f100003 Architecture 2.06+ (POWER7+)
Since the PCR is per-core, the architecture compatibility level and
the corresponding PCR value are stored in the struct kvmppc_vcore, and
are therefore shared between all vcpus in a virtual core.
Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: squash in fix to add missing break statements and documentation]
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER7 and later IBM server processors have a register called the
Program Priority Register (PPR), which controls the priority of
each hardware CPU SMT thread, and affects how fast it runs compared
to other SMT threads. This priority can be controlled by writing to
the PPR or by use of a set of instructions of the form or rN,rN,rN
which are otherwise no-ops but have been defined to set the priority
to particular levels.
This adds code to context switch the PPR when entering and exiting
guests and to make the PPR value accessible through the SET/GET_ONE_REG
interface. When entering the guest, we set the PPR as late as
possible, because if we are setting a low thread priority it will
make the code run slowly from that point on. Similarly, the
first-level interrupt handlers save the PPR value in the PACA very
early on, and set the thread priority to the medium level, so that
the interrupt handling code runs at a reasonable speed.
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds the ability to have a separate LPCR (Logical Partitioning
Control Register) value relating to a guest for each virtual core,
rather than only having a single value for the whole VM. This
corresponds to what real POWER hardware does, where there is a LPCR
per CPU thread but most of the fields are required to have the same
value on all active threads in a core.
The per-virtual-core LPCR can be read and written using the
GET/SET_ONE_REG interface. Userspace can can only modify the
following fields of the LPCR value:
DPFD Default prefetch depth
ILE Interrupt little-endian
TC Translation control (secondary HPT hash group search disable)
We still maintain a per-VM default LPCR value in kvm->arch.lpcr, which
contains bits relating to memory management, i.e. the Virtualized
Partition Memory (VPM) bits and the bits relating to guest real mode.
When this default value is updated, the update needs to be propagated
to the per-vcore values, so we add a kvmppc_update_lpcr() helper to do
that.
Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix whitespace]
Signed-off-by: Alexander Graf <agraf@suse.de>
This allows guests to have a different timebase origin from the host.
This is needed for migration, where a guest can migrate from one host
to another and the two hosts might have a different timebase origin.
However, the timebase seen by the guest must not go backwards, and
should go forwards only by a small amount corresponding to the time
taken for the migration.
Therefore this provides a new per-vcpu value accessed via the one_reg
interface using the new KVM_REG_PPC_TB_OFFSET identifier. This value
defaults to 0 and is not modified by KVM. On entering the guest, this
value is added onto the timebase, and on exiting the guest, it is
subtracted from the timebase.
This is only supported for recent POWER hardware which has the TBU40
(timebase upper 40 bits) register. Writing to the TBU40 register only
alters the upper 40 bits of the timebase, leaving the lower 24 bits
unchanged. This provides a way to modify the timebase for guest
migration without disturbing the synchronization of the timebase
registers across CPU cores. The kernel rounds up the value given
to a multiple of 2^24.
Timebase values stored in KVM structures (struct kvm_vcpu, struct
kvmppc_vcore, etc.) are stored as host timebase values. The timebase
values in the dispatch trace log need to be guest timebase values,
however, since that is read directly by the guest. This moves the
setting of vcpu->arch.dec_expires on guest exit to a point after we
have restored the host timebase so that vcpu->arch.dec_expires is a
host timebase value.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently we are not saving and restoring the SIAR and SDAR registers in
the PMU (performance monitor unit) on guest entry and exit. The result
is that performance monitoring tools in the guest could get false
information about where a program was executing and what data it was
accessing at the time of a performance monitor interrupt. This fixes
it by saving and restoring these registers along with the other PMU
registers on guest entry/exit.
This also provides a way for userspace to access these values for a
vcpu via the one_reg interface.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This provides a facility which is intended for use by KVM, where the
contents of the FP/VSX and VMX (Altivec) registers can be saved away
to somewhere other than the thread_struct when kernel code wants to
use floating point or VMX instructions. This is done by providing a
pointer in the thread_struct to indicate where the state should be
saved to. The giveup_fpu() and giveup_altivec() functions test these
pointers and save state to the indicated location if they are non-NULL.
Note that the MSR_FP/VEC bits in task->thread.regs->msr are still used
to indicate whether the CPU register state is live, even when an
alternate save location is being used.
This also provides load_fp_state() and load_vr_state() functions, which
load up FP/VSX and VMX state from memory into the CPU registers, and
corresponding store_fp_state() and store_vr_state() functions, which
store FP/VSX and VMX state into memory from the CPU registers.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This creates new 'thread_fp_state' and 'thread_vr_state' structures
to store FP/VSX state (including FPSCR) and Altivec/VSX state
(including VSCR), and uses them in the thread_struct. In the
thread_fp_state, the FPRs and VSRs are represented as u64 rather
than double, since we rarely perform floating-point computations
on the values, and this will enable the structures to be used
in KVM code as well. Similarly FPSCR is now a u64 rather than
a structure of two 32-bit values.
This takes the offsets out of the macros such as SAVE_32FPRS,
REST_32FPRS, etc. This enables the same macros to be used for normal
and transactional state, enabling us to delete the transactional
versions of the macros. This also removes the unused do_load_up_fpu
and do_load_up_altivec, which were in fact buggy since they didn't
create large enough stack frames to account for the fact that
load_up_fpu and load_up_altivec are not designed to be called from C
and assume that their caller's stack frame is an interrupt frame.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We've been keeping that field in thread_struct for a while, it contains
the "limit" of the current stack pointer and is meant to be used for
detecting stack overflows.
It has a few problems however:
- First, it was never actually *used* on 64-bit. Set and updated but
not actually exploited
- When switching stack to/from irq and softirq stacks, it's update
is racy unless we hard disable interrupts, which is costly. This
is fine on 32-bit as we don't soft-disable there but not on 64-bit.
Thus rather than fixing 2 in order to implement 1 in some hypothetical
future, let's remove the code completely from 64-bit. In order to avoid
a clutter of ifdef's, we remove the updates from C code completely
during interrupt stack switching, and instead maintain it from the
asm helper that is used to do the stack switching in the first place.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull KVM updates from Gleb Natapov:
"The highlights of the release are nested EPT and pv-ticketlocks
support (hypervisor part, guest part, which is most of the code, goes
through tip tree). Apart of that there are many fixes for all arches"
Fix up semantic conflicts as discussed in the pull request thread..
* 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (88 commits)
ARM: KVM: Add newlines to panic strings
ARM: KVM: Work around older compiler bug
ARM: KVM: Simplify tracepoint text
ARM: KVM: Fix kvm_set_pte assignment
ARM: KVM: vgic: Bump VGIC_NR_IRQS to 256
ARM: KVM: Bugfix: vgic_bytemap_get_reg per cpu regs
ARM: KVM: vgic: fix GICD_ICFGRn access
ARM: KVM: vgic: simplify vgic_get_target_reg
KVM: MMU: remove unused parameter
KVM: PPC: Book3S PR: Rework kvmppc_mmu_book3s_64_xlate()
KVM: PPC: Book3S PR: Make instruction fetch fallback work for system calls
KVM: PPC: Book3S PR: Don't corrupt guest state when kernel uses VMX
KVM: x86: update masterclock when kvmclock_offset is calculated (v2)
KVM: PPC: Book3S: Fix compile error in XICS emulation
KVM: PPC: Book3S PR: return appropriate error when allocation fails
arch: powerpc: kvm: add signed type cast for comparation
KVM: x86: add comments where MMIO does not return to the emulator
KVM: vmx: count exits to userspace during invalid guest emulation
KVM: rename __kvm_io_bus_sort_cmp to kvm_io_bus_cmp
kvm: optimize away THP checks in kvm_is_mmio_pfn()
...
If a transaction is rolled back, the Target Address Register (TAR), Processor
Priority Register (PPR) and Data Stream Control Register (DSCR) should be
restored to the checkpointed values before the transaction began. Any changes
to these SPRs inside the transaction should not be visible in the abort
handler.
Currently Linux doesn't save or restore the checkpointed TAR, PPR or DSCR. If
we preempt a processes inside a transaction which has modified any of these, on
process restore, that same transaction may be aborted we but we won't see the
checkpointed versions of these SPRs.
This adds checkpointed versions of these SPRs to the thread_struct and adds the
save/restore of these three SPRs to the treclaim/trechkpt code.
Without this if any of these SPRs are modified during a transaction, users may
incorrectly see a speculated SPR value even if the transaction is aborted.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: <stable@vger.kernel.org> [v3.10]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Unlike the other general-purpose SPRs, SPRG3 can be read by usermode
code, and is used in recent kernels to store the CPU and NUMA node
numbers so that they can be read by VDSO functions. Thus we need to
load the guest's SPRG3 value into the real SPRG3 register when entering
the guest, and restore the host's value when exiting the guest. We don't
need to save the guest SPRG3 value when exiting the guest as usermode
code can't modify SPRG3.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
In commit 59affcd "Context switch more PMU related SPRs" I added more
PMU SPRs to thread_struct, later modified in commit b11ae95. To add
insult to injury it turns out we don't need to switch MMCRA as it's
only user readable, and the value is recomputed by the PMU code.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
On BookE (Branch taken + Single Step) is as same as Branch Taken
on BookS and in Linux we simulate BookS behavior for BookE as well.
When doing so, in Branch taken handling we want to set DBCR0_IC but
we update the current->thread->dbcr0 and not DBCR0.
Now on 64bit the current->thread.dbcr0 (and other debug registers)
is synchronized ONLY on context switch flow. But after handling
Branch taken in debug exception if we return back to user space
without context switch then single stepping change (DBCR0_ICMP)
does not get written in h/w DBCR0 and Instruction Complete exception
does not happen.
This fixes using ptrace reliably on BookE-PowerPC
lmbench latency test (lat_syscall) Results are (they varies a little
on each run)
1) ./lat_syscall <action> /dev/shm/uImage
action: Open read write stat fstat null
Before: 3.8618 0.2017 0.2851 1.6789 0.2256 0.0856
After: 3.8580 0.2017 0.2851 1.6955 0.2255 0.0856
1) ./lat_syscall -P 2 -N 10 <action> /dev/shm/uImage
action: Open read write stat fstat null
Before: 4.1388 0.2238 0.3066 1.7106 0.2256 0.0856
After: 4.1413 0.2236 0.3062 1.7107 0.2256 0.0856
[ Slightly modified to avoid extra branch in the fast path
on Book3S and fix build on all non-BookE 64-bit -- BenH
]
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
In commit 9353374 "Context switch the new EBB SPRs" we added support for
context switching some new EBB SPRs. However despite four of us signing
off on that patch we missed some. To be fair these are not actually new
SPRs, but they are now potentially user accessible so need to be context
switched.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull kvm updates from Gleb Natapov:
"Highlights of the updates are:
general:
- new emulated device API
- legacy device assignment is now optional
- irqfd interface is more generic and can be shared between arches
x86:
- VMCS shadow support and other nested VMX improvements
- APIC virtualization and Posted Interrupt hardware support
- Optimize mmio spte zapping
ppc:
- BookE: in-kernel MPIC emulation with irqfd support
- Book3S: in-kernel XICS emulation (incomplete)
- Book3S: HV: migration fixes
- BookE: more debug support preparation
- BookE: e6500 support
ARM:
- reworking of Hyp idmaps
s390:
- ioeventfd for virtio-ccw
And many other bug fixes, cleanups and improvements"
* tag 'kvm-3.10-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (204 commits)
kvm: Add compat_ioctl for device control API
KVM: x86: Account for failing enable_irq_window for NMI window request
KVM: PPC: Book3S: Add API for in-kernel XICS emulation
kvm/ppc/mpic: fix missing unlock in set_base_addr()
kvm/ppc: Hold srcu lock when calling kvm_io_bus_read/write
kvm/ppc/mpic: remove users
kvm/ppc/mpic: fix mmio region lists when multiple guests used
kvm/ppc/mpic: remove default routes from documentation
kvm: KVM_CAP_IOMMU only available with device assignment
ARM: KVM: iterate over all CPUs for CPU compatibility check
KVM: ARM: Fix spelling in error message
ARM: KVM: define KVM_ARM_MAX_VCPUS unconditionally
KVM: ARM: Fix API documentation for ONE_REG encoding
ARM: KVM: promote vfp_host pointer to generic host cpu context
ARM: KVM: add architecture specific hook for capabilities
ARM: KVM: perform HYP initilization for hotplugged CPUs
ARM: KVM: switch to a dual-step HYP init code
ARM: KVM: rework HYP page table freeing
ARM: KVM: enforce maximum size for identity mapped code
ARM: KVM: move to a KVM provided HYP idmap
...
This context switches the new Event Based Branching (EBB) SPRs. The three new
SPRs are:
- Event Based Branch Handler Register (EBBHR)
- Event Based Branch Return Register (EBBRR)
- Branch Event Status and Control Register (BESCR)
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Currently, we wake up a CPU by sending a host IPI with
smp_send_reschedule() to thread 0 of that core, which will take all
threads out of the guest, and cause them to re-evaluate their
interrupt status on the way back in.
This adds a mechanism to differentiate real host IPIs from IPIs sent
by KVM for guest threads to poke each other, in order to target the
guest threads precisely when possible and avoid that global switch of
the core to host state.
We then use this new facility in the in-kernel XICS code.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
At present, the KVM_GET_DIRTY_LOG ioctl doesn't report modifications
done by the host to the virtual processor areas (VPAs) and dispatch
trace logs (DTLs) registered by the guest. This is because those
modifications are done either in real mode or in the host kernel
context, and in neither case does the access go through the guest's
HPT, and thus no change (C) bit gets set in the guest's HPT.
However, the changes done by the host do need to be tracked so that
the modified pages get transferred when doing live migration. In
order to track these modifications, this adds a dirty flag to the
struct representing the VPA/DTL areas, and arranges to set the flag
when the VPA/DTL gets modified by the host. Then, when we are
collecting the dirty log, we also check the dirty flags for the
VPA and DTL for each vcpu and set the relevant bit in the dirty log
if necessary. Doing this also means we now need to keep track of
the guest physical address of the VPA/DTL areas.
So as not to lose track of modifications to a VPA/DTL area when it gets
unregistered, or when a new area gets registered in its place, we need
to transfer the dirty state to the rmap chain. This adds code to
kvmppc_unpin_guest_page() to do that if the area was dirty. To simplify
that code, we now require that all VPA, DTL and SLB shadow buffer areas
fit within a single host page. Guests already comply with this
requirement because pHyp requires that these areas not cross a 4k
boundary.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Installed debug handler will be used for guest debug support
and debug facility emulation features (patches for these
features will follow this patch).
Signed-off-by: Liu Yu <yu.liu@freescale.com>
[bharat.bhushan@freescale.com: Substantial changes]
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Add transactional memory paca scratch register to show_regs. This is useful
for debugging.
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This adds new macros for saving and restoring checkpointed architected state
from and to the thread_struct.
It also adds some debugging macros for when your brain explodes trying to debug
your transactional memory enabled kernel.
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The CFAR (Come-From Address Register) is a useful debugging aid that
exists on POWER7 processors. Currently HV KVM doesn't save or restore
the CFAR register for guest vcpus, making the CFAR of limited use in
guests.
This adds the necessary code to capture the CFAR value saved in the
early exception entry code (it has to be saved before any branch is
executed), save it in the vcpu.arch struct, and restore it on entry
to the guest.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Like other places, use thread_struct to get vcpu reference.
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch adds support for enabling and context switching the Target
Address Register in Power8. The TAR is a new special purpose register
that can be used for computed branches with the bctar[l] (branch
conditional to TAR) instruction in the same manner as the count and link
registers.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[PATCH 4/6] powerpc: Define ppr in thread_struct
ppr in thread_struct is used to save PPR and restore it before process exits
from kernel.
This patch sets the default priority to 3 when tasks are created such
that users can use 4 for higher priority tasks.
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When we change or remove a HPT (hashed page table) entry, we can do
either a global TLB invalidation (tlbie) that works across the whole
machine, or a local invalidation (tlbiel) that only affects this core.
Currently we do local invalidations if the VM has only one vcpu or if
the guest requests it with the H_LOCAL flag, though the guest Linux
kernel currently doesn't ever use H_LOCAL. Then, to cope with the
possibility that vcpus moving around to different physical cores might
expose stale TLB entries, there is some code in kvmppc_hv_entry to
flush the whole TLB of entries for this VM if either this vcpu is now
running on a different physical core from where it last ran, or if this
physical core last ran a different vcpu.
There are a number of problems on POWER7 with this as it stands:
- The TLB invalidation is done per thread, whereas it only needs to be
done per core, since the TLB is shared between the threads.
- With the possibility of the host paging out guest pages, the use of
H_LOCAL by an SMP guest is dangerous since the guest could possibly
retain and use a stale TLB entry pointing to a page that had been
removed from the guest.
- The TLB invalidations that we do when a vcpu moves from one physical
core to another are unnecessary in the case of an SMP guest that isn't
using H_LOCAL.
- The optimization of using local invalidations rather than global should
apply to guests with one virtual core, not just one vcpu.
(None of this applies on PPC970, since there we always have to
invalidate the whole TLB when entering and leaving the guest, and we
can't support paging out guest memory.)
To fix these problems and simplify the code, we now maintain a simple
cpumask of which cpus need to flush the TLB on entry to the guest.
(This is indexed by cpu, though we only ever use the bits for thread
0 of each core.) Whenever we do a local TLB invalidation, we set the
bits for every cpu except the bit for thread 0 of the core that we're
currently running on. Whenever we enter a guest, we test and clear the
bit for our core, and flush the TLB if it was set.
On initial startup of the VM, and when resetting the HPT, we set all the
bits in the need_tlb_flush cpumask, since any core could potentially have
stale TLB entries from the previous VM to use the same LPID, or the
previous contents of the HPT.
Then, we maintain a count of the number of online virtual cores, and use
that when deciding whether to use a local invalidation rather than the
number of online vcpus. The code to make that decision is extracted out
into a new function, global_invalidates(). For multi-core guests on
POWER7 (i.e. when we are using mmu notifiers), we now never do local
invalidations regardless of the H_LOCAL flag.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Critical exception on 64-bit booke uses user-visible SPRG3 as scratch.
Restore VDSO information in SPRG3 on exception prolog.
Use a common sprg3 field in PACA for all powerpc64 architectures.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
During a context switch we always restore the per thread DSCR value.
If we aren't doing explicit DSCR management
(ie thread.dscr_inherit == 0) and the default DSCR changed while
the process has been sleeping we end up with the wrong value.
Check thread.dscr_inherit and select the default DSCR or per thread
DSCR as required.
This was found with the following test case, when running with
more threads than CPUs (ie forcing context switching):
http://ozlabs.org/~anton/junkcode/dscr_default_test.c
With the four patches applied I can run a combination of all
test cases successfully at the same time:
http://ozlabs.org/~anton/junkcode/dscr_default_test.chttp://ozlabs.org/~anton/junkcode/dscr_explicit_test.chttp://ozlabs.org/~anton/junkcode/dscr_inherit_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> # 3.0+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We have a request for a fast method of getting CPU and NUMA node IDs
from userspace. This patch implements a getcpu VDSO function,
similar to x86.
Ben suggested we use SPRG3 which is userspace readable. SPRG3 can be
modified by a KVM guest, so we save the SPRG3 value in the paca and
restore it when transitioning from the guest to the host.
I have a glibc patch that implements sched_getcpu on top of this.
Testing on a POWER7:
baseline: 538 cycles
vdso: 30 cycles
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull KVM changes from Avi Kivity:
"Changes include additional instruction emulation, page-crossing MMIO,
faster dirty logging, preventing the watchdog from killing a stopped
guest, module autoload, a new MSI ABI, and some minor optimizations
and fixes. Outside x86 we have a small s390 and a very large ppc
update.
Regarding the new (for kvm) rebaseless workflow, some of the patches
that were merged before we switch trees had to be rebased, while
others are true pulls. In either case the signoffs should be correct
now."
Fix up trivial conflicts in Documentation/feature-removal-schedule.txt
arch/powerpc/kvm/book3s_segment.S and arch/x86/include/asm/kvm_para.h.
I suspect the kvm_para.h resolution ends up doing the "do I have cpuid"
check effectively twice (it was done differently in two different
commits), but better safe than sorry ;)
* 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (125 commits)
KVM: make asm-generic/kvm_para.h have an ifdef __KERNEL__ block
KVM: s390: onereg for timer related registers
KVM: s390: epoch difference and TOD programmable field
KVM: s390: KVM_GET/SET_ONEREG for s390
KVM: s390: add capability indicating COW support
KVM: Fix mmu_reload() clash with nested vmx event injection
KVM: MMU: Don't use RCU for lockless shadow walking
KVM: VMX: Optimize %ds, %es reload
KVM: VMX: Fix %ds/%es clobber
KVM: x86 emulator: convert bsf/bsr instructions to emulate_2op_SrcV_nobyte()
KVM: VMX: unlike vmcs on fail path
KVM: PPC: Emulator: clean up SPR reads and writes
KVM: PPC: Emulator: clean up instruction parsing
kvm/powerpc: Add new ioctl to retreive server MMU infos
kvm/book3s: Make kernel emulated H_PUT_TCE available for "PR" KVM
KVM: PPC: bookehv: Fix r8/r13 storing in level exception handler
KVM: PPC: Book3S: Enable IRQs during exit handling
KVM: PPC: Fix PR KVM on POWER7 bare metal
KVM: PPC: Fix stbux emulation
KVM: PPC: bookehv: Use lwz/stw instead of PPC_LL/PPC_STL for 32-bit fields
...
Remove all the iseries specific fields in the lppaca.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Commits 2f5cdd5487 ("KVM: PPC: Book3S HV: Make secondary threads more
robust against stray IPIs") and 1c2066b0f7 ("KVM: PPC: Book3S HV: Make
virtual processor area registration more robust") added fields to
struct kvm_vcpu_arch inside #ifdef CONFIG_KVM_BOOK3S_64_HV regions,
and added lines to arch/powerpc/kernel/asm-offsets.c to generate
assembler constants for their offsets. Unfortunately this led to
compile errors on Book 3S machines for configs that had KVM enabled
but not CONFIG_KVM_BOOK3S_64_HV. This fixes the problem by moving
the offending lines inside #ifdef CONFIG_KVM_BOOK3S_64_HV regions.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
The PAPR API allows three sorts of per-virtual-processor areas to be
registered (VPA, SLB shadow buffer, and dispatch trace log), and
furthermore, these can be registered and unregistered for another
virtual CPU. Currently we just update the vcpu fields pointing to
these areas at the time of registration or unregistration. If this
is done on another vcpu, there is the possibility that the target vcpu
is using those fields at the time and could end up using a bogus
pointer and corrupting memory.
This fixes the race by making the target cpu itself do the update, so
we can be sure that the update happens at a time when the fields
aren't being used. Each area now has a struct kvmppc_vpa which is
used to manage these updates. There is also a spinlock which protects
access to all of the kvmppc_vpa structs, other than to the pinned_addr
fields. (We could have just taken the spinlock when using the vpa,
slb_shadow or dtl fields, but that would mean taking the spinlock on
every guest entry and exit.)
This also changes 'struct dtl' (which was undefined) to 'struct dtl_entry',
which is what the rest of the kernel uses.
Thanks to Michael Ellerman <michael@ellerman.id.au> for pointing out
the need to initialize vcpu->arch.vpa_update_lock.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Currently on POWER7, if we are running the guest on a core and we don't
need all the hardware threads, we do nothing to ensure that the unused
threads aren't executing in the kernel (other than checking that they
are offline). We just assume they're napping and we don't do anything
to stop them trying to enter the kernel while the guest is running.
This means that a stray IPI can wake up the hardware thread and it will
then try to enter the kernel, but since the core is in guest context,
it will execute code from the guest in hypervisor mode once it turns the
MMU on, which tends to lead to crashes or hangs in the host.
This fixes the problem by adding two new one-byte flags in the
kvmppc_host_state structure in the PACA which are used to interlock
between the primary thread and the unused secondary threads when entering
the guest. With these flags, the primary thread can ensure that the
unused secondaries are not already in kernel mode (i.e. handling a stray
IPI) and then indicate that they should not try to enter the kernel
if they do get woken for any reason. Instead they will go into KVM code,
find that there is no vcpu to run, acknowledge and clear the IPI and go
back to nap mode.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Chips such as e500mc that implement category E.HV in Power ISA 2.06
provide hardware virtualization features, including a new MSR mode for
guest state. The guest OS can perform many operations without trapping
into the hypervisor, including transitions to and from guest userspace.
Since we can use SRR1[GS] to reliably tell whether an exception came from
guest state, instead of messing around with IVPR, we use DO_KVM similarly
to book3s.
Current issues include:
- Machine checks from guest state are not routed to the host handler.
- The guest can cause a host oops by executing an emulated instruction
in a page that lacks read permission. Existing e500/4xx support has
the same problem.
Includes work by Ashish Kalra <Ashish.Kalra@freescale.com>,
Varun Sethi <Varun.Sethi@freescale.com>, and
Liu Yu <yu.liu@freescale.com>.
Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: remove pt_regs usage]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Pull kvm updates from Avi Kivity:
"Changes include timekeeping improvements, support for assigning host
PCI devices that share interrupt lines, s390 user-controlled guests, a
large ppc update, and random fixes."
This is with the sign-off's fixed, hopefully next merge window we won't
have rebased commits.
* 'kvm-updates/3.4' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits)
KVM: Convert intx_mask_lock to spin lock
KVM: x86: fix kvm_write_tsc() TSC matching thinko
x86: kvmclock: abstract save/restore sched_clock_state
KVM: nVMX: Fix erroneous exception bitmap check
KVM: Ignore the writes to MSR_K7_HWCR(3)
KVM: MMU: make use of ->root_level in reset_rsvds_bits_mask
KVM: PMU: add proper support for fixed counter 2
KVM: PMU: Fix raw event check
KVM: PMU: warn when pin control is set in eventsel msr
KVM: VMX: Fix delayed load of shared MSRs
KVM: use correct tlbs dirty type in cmpxchg
KVM: Allow host IRQ sharing for assigned PCI 2.3 devices
KVM: Ensure all vcpus are consistent with in-kernel irqchip settings
KVM: x86 emulator: Allow PM/VM86 switch during task switch
KVM: SVM: Fix CPL updates
KVM: x86 emulator: VM86 segments must have DPL 3
KVM: x86 emulator: Fix task switch privilege checks
arch/powerpc/kvm/book3s_hv.c: included linux/sched.h twice
KVM: x86 emulator: correctly mask pmc index bits in RDPMC instruction emulation
KVM: mmu_notifier: Flush TLBs before releasing mmu_lock
...
The current implementation of lazy interrupts handling has some
issues that this tries to address.
We don't do the various workarounds we need to do when re-enabling
interrupts in some cases such as when returning from an interrupt
and thus we may still lose or get delayed decrementer or doorbell
interrupts.
The current scheme also makes it much harder to handle the external
"edge" interrupts provided by some BookE processors when using the
EPR facility (External Proxy) and the Freescale Hypervisor.
Additionally, we tend to keep interrupts hard disabled in a number
of cases, such as decrementer interrupts, external interrupts, or
when a masked decrementer interrupt is pending. This is sub-optimal.
This is an attempt at fixing it all in one go by reworking the way
we do the lazy interrupt disabling from the ground up.
The base idea is to replace the "hard_enabled" field with a
"irq_happened" field in which we store a bit mask of what interrupt
occurred while soft-disabled.
When re-enabling, either via arch_local_irq_restore() or when returning
from an interrupt, we can now decide what to do by testing bits in that
field.
We then implement replaying of the missed interrupts either by
re-using the existing exception frame (in exception exit case) or via
the creation of a new one from an assembly trampoline (in the
arch_local_irq_enable case).
This removes the need to play with the decrementer to try to create
fake interrupts, among others.
In addition, this adds a few refinements:
- We no longer hard disable decrementer interrupts that occur
while soft-disabled. We now simply bump the decrementer back to max
(on BookS) or leave it stopped (on BookE) and continue with hard interrupts
enabled, which means that we'll potentially get better sample quality from
performance monitor interrupts.
- Timer, decrementer and doorbell interrupts now hard-enable
shortly after removing the source of the interrupt, which means
they no longer run entirely hard disabled. Again, this will improve
perf sample quality.
- On Book3E 64-bit, we now make the performance monitor interrupt
act as an NMI like Book3S (the necessary C code for that to work
appear to already be present in the FSL perf code, notably calling
nmi_enter instead of irq_enter). (This also fixes a bug where BookE
perfmon interrupts could clobber r14 ... oops)
- We could make "masked" decrementer interrupts act as NMIs when doing
timer-based perf sampling to improve the sample quality.
Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
v2:
- Add hard-enable to decrementer, timer and doorbells
- Fix CR clobber in masked irq handling on BookE
- Make embedded perf interrupt act as an NMI
- Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want
to retrigger an interrupt without preventing hard-enable
v3:
- Fix or vs. ori bug on Book3E
- Fix enabling of interrupts for some exceptions on Book3E
v4:
- Fix resend of doorbells on return from interrupt on Book3E
v5:
- Rebased on top of my latest series, which involves some significant
rework of some aspects of the patch.
v6:
- 32-bit compile fix
- more compile fixes with various .config combos
- factor out the asm code to soft-disable interrupts
- remove the C wrapper around preempt_schedule_irq
v7:
- Fix a bug with hard irq state tracking on native power7
This provides the low-level support for MMIO emulation in Book3S HV
guests. When the guest tries to map a page which is not covered by
any memslot, that page is taken to be an MMIO emulation page. Instead
of inserting a valid HPTE, we insert an HPTE that has the valid bit
clear but another hypervisor software-use bit set, which we call
HPTE_V_ABSENT, to indicate that this is an absent page. An
absent page is treated much like a valid page as far as guest hcalls
(H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that
an absent HPTE doesn't need to be invalidated with tlbie since it
was never valid as far as the hardware is concerned.
When the guest accesses a page for which there is an absent HPTE, it
will take a hypervisor data storage interrupt (HDSI) since we now set
the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults
looks up the hash table and if it finds an absent HPTE mapping the
requested virtual address, will switch to kernel mode and handle the
fault in kvmppc_book3s_hv_page_fault(), which at present just calls
kvmppc_hv_emulate_mmio() to set up the MMIO emulation.
This is based on an earlier patch by Benjamin Herrenschmidt, but since
heavily reworked.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
This allows additional registers to be accessed by the guest
in PR-mode KVM without trapping.
SPRG4-7 are readable from userspace. On booke, KVM will sync
these registers when it enters the guest, so that accesses from
guest userspace will work. The guest kernel, OTOH, must consistently
use either the real registers or the shared area between exits. This
also applies to the already-paravirted SPRG3.
On non-booke, it's not clear to what extent SPRG4-7 are supported
(they're not architected for book3s, but exist on at least some classic
chips). They are copied in the get/set regs ioctls, but I do not see any
non-booke emulation. I also do not see any syncing with real registers
(in PR-mode) including the user-readable SPRG3. This patch should not
make that situation any worse.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
This fixes a problem where a CPU thread coming out of nap mode can
think it has valid values in the nonvolatile GPRs (r14 - r31) as saved
away in power7_idle, but in fact the values have been trashed because
the thread was used for KVM in the mean time. The result is that the
thread crashes because code that called power7_idle (e.g.,
pnv_smp_cpu_kill_self()) goes to use values in registers that have
been trashed.
The bit field in SRR1 that tells whether state was lost only reflects
the most recent nap, which may not have been the nap instruction in
power7_idle. So we need an extra PACA field to indicate that state
has been lost even if SRR1 indicates that the most recent nap didn't
lose state. We clear this field when saving the state in power7_idle,
we set it to a non-zero value when we use the thread for KVM, and we
test it in power7_wakeup_noloss.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (106 commits)
powerpc/p3060qds: Add support for P3060QDS board
powerpc/83xx: Add shutdown request support to MCU handling on MPC8349 MITX
powerpc/85xx: Make kexec to interate over online cpus
powerpc/fsl_booke: Fix comment in head_fsl_booke.S
powerpc/85xx: issue 15 EOI after core reset for FSL CoreNet devices
powerpc/8xxx: Fix interrupt handling in MPC8xxx GPIO driver
powerpc/85xx: Add 'fsl,pq3-gpio' compatiable for GPIO driver
powerpc/86xx: Correct Gianfar support for GE boards
powerpc/cpm: Clear muram before it is in use.
drivers/virt: add ioctl for 32-bit compat on 64-bit to fsl-hv-manager
powerpc/fsl_msi: add support for "msi-address-64" property
powerpc/85xx: Setup secondary cores PIR with hard SMP id
powerpc/fsl-booke: Fix settlbcam for 64-bit
powerpc/85xx: Adding DCSR node to dtsi device trees
powerpc/85xx: clean up FPGA device tree nodes for Freecsale QorIQ boards
powerpc/85xx: fix PHYS_64BIT selection for P1022DS
powerpc/fsl-booke: Fix setup_initial_memory_limit to not blindly map
powerpc: respect mem= setting for early memory limit setup
powerpc: Update corenet64_smp_defconfig
powerpc: Update mpc85xx/corenet 32-bit defconfigs
...
Fix up trivial conflicts in:
- arch/powerpc/configs/40x/hcu4_defconfig
removed stale file, edited elsewhere
- arch/powerpc/include/asm/udbg.h, arch/powerpc/kernel/udbg.c:
added opal and gelic drivers vs added ePAPR driver
- drivers/tty/serial/8250.c
moved UPIO_TSI to powerpc vs removed UPIO_DWAPB support
With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per
core), whenever a CPU goes idle, we have to pull all the other
hardware threads in the core out of the guest, because the H_CEDE
hcall is handled in the kernel. This is inefficient.
This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall
in real mode. When a guest vcpu does an H_CEDE hcall, we now only
exit to the kernel if all the other vcpus in the same core are also
idle. Otherwise we mark this vcpu as napping, save state that could
be lost in nap mode (mainly GPRs and FPRs), and execute the nap
instruction. When the thread wakes up, because of a decrementer or
external interrupt, we come back in at kvm_start_guest (from the
system reset interrupt vector), find the `napping' flag set in the
paca, and go to the resume path.
This has some other ramifications. First, when starting a core, we
now start all the threads, both those that are immediately runnable and
those that are idle. This is so that we don't have to pull all the
threads out of the guest when an idle thread gets a decrementer interrupt
and wants to start running. In fact the idle threads will all start
with the H_CEDE hcall returning; being idle they will just do another
H_CEDE immediately and go to nap mode.
This required some changes to kvmppc_run_core() and kvmppc_run_vcpu().
These functions have been restructured to make them simpler and clearer.
We introduce a level of indirection in the wait queue that gets woken
when external and decrementer interrupts get generated for a vcpu, so
that we can have the 4 vcpus in a vcore using the same wait queue.
We need this because the 4 vcpus are being handled by one thread.
Secondly, when we need to exit from the guest to the kernel, we now
have to generate an IPI for any napping threads, because an HDEC
interrupt doesn't wake up a napping thread.
Thirdly, we now need to be able to handle virtual external interrupts
and decrementer interrupts becoming pending while a thread is napping,
and deliver those interrupts to the guest when the thread wakes.
This is done in kvmppc_cede_reentry, just before fast_guest_return.
Finally, since we are not using the generic kvm_vcpu_block for book3s_hv,
and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef
from kvm_arch_vcpu_runnable.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This simplifies the way that the book3s_pr makes the transition to
real mode when entering the guest. We now call kvmppc_entry_trampoline
(renamed from kvmppc_rmcall) in the base kernel using a normal function
call instead of doing an indirect call through a pointer in the vcpu.
If kvm is a module, the module loader takes care of generating a
trampoline as it does for other calls to functions outside the module.
kvmppc_entry_trampoline then disables interrupts and jumps to
kvmppc_handler_trampoline_enter in real mode using an rfi[d].
That then uses the link register as the address to return to
(potentially in module space) when the guest exits.
This also simplifies the way that we call the Linux interrupt handler
when we exit the guest due to an external, decrementer or performance
monitor interrupt. Instead of turning on the MMU, then deciding that
we need to call the Linux handler and turning the MMU back off again,
we now go straight to the handler at the point where we would turn the
MMU on. The handler will then return to the virtual-mode code
(potentially in the module).
Along the way, this moves the setting and clearing of the HID5 DCBZ32
bit into real-mode interrupts-off code, and also makes sure that
we clear the MSR[RI] bit before loading values into SRR0/1.
The net result is that we no longer need any code addresses to be
stored in vcpu->arch.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
OPAL can handle various interrupt for us such as Machine Checks (it
performs all sorts of recovery tasks and passes back control to us with
informations about the error), Hardware Management Interrupts and Softpatch
interrupts.
This wires up the mechanisms and prints out specific informations returned
by HAL when a machine check occurs.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (99 commits)
drivers/virt: add missing linux/interrupt.h to fsl_hypervisor.c
powerpc/85xx: fix mpic configuration in CAMP mode
powerpc: Copy back TIF flags on return from softirq stack
powerpc/64: Make server perfmon only built on ppc64 server devices
powerpc/pseries: Fix hvc_vio.c build due to recent changes
powerpc: Exporting boot_cpuid_phys
powerpc: Add CFAR to oops output
hvc_console: Add kdb support
powerpc/pseries: Fix hvterm_raw_get_chars to accept < 16 chars, fixing xmon
powerpc/irq: Quieten irq mapping printks
powerpc: Enable lockup and hung task detectors in pseries and ppc64 defeconfigs
powerpc: Add mpt2sas driver to pseries and ppc64 defconfig
powerpc: Disable IRQs off tracer in ppc64 defconfig
powerpc: Sync pseries and ppc64 defconfigs
powerpc/pseries/hvconsole: Fix dropped console output
hvc_console: Improve tty/console put_chars handling
powerpc/kdump: Fix timeout in crash_kexec_wait_realmode
powerpc/mm: Fix output of total_ram.
powerpc/cpufreq: Add cpufreq driver for Momentum Maple boards
powerpc: Correct annotations of pmu registration functions
...
Fix up trivial Kconfig/Makefile conflicts in arch/powerpc, drivers, and
drivers/cpufreq
This adds support for running KVM guests in supervisor mode on those
PPC970 processors that have a usable hypervisor mode. Unfortunately,
Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to
1), but the YDL PowerStation does have a usable hypervisor mode.
There are several differences between the PPC970 and POWER7 in how
guests are managed. These differences are accommodated using the
CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature
bits. Notably, on PPC970:
* The LPCR, LPID or RMOR registers don't exist, and the functions of
those registers are provided by bits in HID4 and one bit in HID0.
* External interrupts can be directed to the hypervisor, but unlike
POWER7 they are masked by MSR[EE] in non-hypervisor modes and use
SRR0/1 not HSRR0/1.
* There is no virtual RMA (VRMA) mode; the guest must use an RMO
(real mode offset) area.
* The TLB entries are not tagged with the LPID, so it is necessary to
flush the whole TLB on partition switch. Furthermore, when switching
partitions we have to ensure that no other CPU is executing the tlbie
or tlbsync instructions in either the old or the new partition,
otherwise undefined behaviour can occur.
* The PMU has 8 counters (PMC registers) rather than 6.
* The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist.
* The SLB has 64 entries rather than 32.
* There is no mediated external interrupt facility, so if we switch to
a guest that has a virtual external interrupt pending but the guest
has MSR[EE] = 0, we have to arrange to have an interrupt pending for
it so that we can get control back once it re-enables interrupts. We
do that by sending ourselves an IPI with smp_send_reschedule after
hard-disabling interrupts.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds infrastructure which will be needed to allow book3s_hv KVM to
run on older POWER processors, including PPC970, which don't support
the Virtual Real Mode Area (VRMA) facility, but only the Real Mode
Offset (RMO) facility. These processors require a physically
contiguous, aligned area of memory for each guest. When the guest does
an access in real mode (MMU off), the address is compared against a
limit value, and if it is lower, the address is ORed with an offset
value (from the Real Mode Offset Register (RMOR)) and the result becomes
the real address for the access. The size of the RMA has to be one of
a set of supported values, which usually includes 64MB, 128MB, 256MB
and some larger powers of 2.
Since we are unlikely to be able to allocate 64MB or more of physically
contiguous memory after the kernel has been running for a while, we
allocate a pool of RMAs at boot time using the bootmem allocator. The
size and number of the RMAs can be set using the kvm_rma_size=xx and
kvm_rma_count=xx kernel command line options.
KVM exports a new capability, KVM_CAP_PPC_RMA, to signal the availability
of the pool of preallocated RMAs. The capability value is 1 if the
processor can use an RMA but doesn't require one (because it supports
the VRMA facility), or 2 if the processor requires an RMA for each guest.
This adds a new ioctl, KVM_ALLOCATE_RMA, which allocates an RMA from the
pool and returns a file descriptor which can be used to map the RMA. It
also returns the size of the RMA in the argument structure.
Having an RMA means we will get multiple KMV_SET_USER_MEMORY_REGION
ioctl calls from userspace. To cope with this, we now preallocate the
kvm->arch.ram_pginfo array when the VM is created with a size sufficient
for up to 64GB of guest memory. Subsequently we will get rid of this
array and use memory associated with each memslot instead.
This moves most of the code that translates the user addresses into
host pfns (page frame numbers) out of kvmppc_prepare_vrma up one level
to kvmppc_core_prepare_memory_region. Also, instead of having to look
up the VMA for each page in order to check the page size, we now check
that the pages we get are compound pages of 16MB. However, if we are
adding memory that is mapped to an RMA, we don't bother with calling
get_user_pages_fast and instead just offset from the base pfn for the
RMA.
Typically the RMA gets added after vcpus are created, which makes it
inconvenient to have the LPCR (logical partition control register) value
in the vcpu->arch struct, since the LPCR controls whether the processor
uses RMA or VRMA for the guest. This moves the LPCR value into the
kvm->arch struct and arranges for the MER (mediated external request)
bit, which is the only bit that varies between vcpus, to be set in
assembly code when going into the guest if there is a pending external
interrupt request.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This lifts the restriction that book3s_hv guests can only run one
hardware thread per core, and allows them to use up to 4 threads
per core on POWER7. The host still has to run single-threaded.
This capability is advertised to qemu through a new KVM_CAP_PPC_SMT
capability. The return value of the ioctl querying this capability
is the number of vcpus per virtual CPU core (vcore), currently 4.
To use this, the host kernel should be booted with all threads
active, and then all the secondary threads should be offlined.
This will put the secondary threads into nap mode. KVM will then
wake them from nap mode and use them for running guest code (while
they are still offline). To wake the secondary threads, we send
them an IPI using a new xics_wake_cpu() function, implemented in
arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage
we assume that the platform has a XICS interrupt controller and
we are using icp-native.c to drive it. Since the woken thread will
need to acknowledge and clear the IPI, we also export the base
physical address of the XICS registers using kvmppc_set_xics_phys()
for use in the low-level KVM book3s code.
When a vcpu is created, it is assigned to a virtual CPU core.
The vcore number is obtained by dividing the vcpu number by the
number of threads per core in the host. This number is exported
to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes
to run the guest in single-threaded mode, it should make all vcpu
numbers be multiples of the number of threads per core.
We distinguish three states of a vcpu: runnable (i.e., ready to execute
the guest), blocked (that is, idle), and busy in host. We currently
implement a policy that the vcore can run only when all its threads
are runnable or blocked. This way, if a vcpu needs to execute elsewhere
in the kernel or in qemu, it can do so without being starved of CPU
by the other vcpus.
When a vcore starts to run, it executes in the context of one of the
vcpu threads. The other vcpu threads all go to sleep and stay asleep
until something happens requiring the vcpu thread to return to qemu,
or to wake up to run the vcore (this can happen when another vcpu
thread goes from busy in host state to blocked).
It can happen that a vcpu goes from blocked to runnable state (e.g.
because of an interrupt), and the vcore it belongs to is already
running. In that case it can start to run immediately as long as
the none of the vcpus in the vcore have started to exit the guest.
We send the next free thread in the vcore an IPI to get it to start
to execute the guest. It synchronizes with the other threads via
the vcore->entry_exit_count field to make sure that it doesn't go
into the guest if the other vcpus are exiting by the time that it
is ready to actually enter the guest.
Note that there is no fixed relationship between the hardware thread
number and the vcpu number. Hardware threads are assigned to vcpus
as they become runnable, so we will always use the lower-numbered
hardware threads in preference to higher-numbered threads if not all
the vcpus in the vcore are runnable, regardless of which vcpus are
runnable.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds the infrastructure for handling PAPR hcalls in the kernel,
either early in the guest exit path while we are still in real mode,
or later once the MMU has been turned back on and we are in the full
kernel context. The advantage of handling hcalls in real mode if
possible is that we avoid two partition switches -- and this will
become more important when we support SMT4 guests, since a partition
switch means we have to pull all of the threads in the core out of
the guest. The disadvantage is that we can only access the kernel
linear mapping, not anything vmalloced or ioremapped, since the MMU
is off.
This also adds code to handle the following hcalls in real mode:
H_ENTER Add an HPTE to the hashed page table
H_REMOVE Remove an HPTE from the hashed page table
H_READ Read HPTEs from the hashed page table
H_PROTECT Change the protection bits in an HPTE
H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table
H_SET_DABR Set the data address breakpoint register
Plus code to handle the following hcalls in the kernel:
H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives
H_PROD Wake up a ceded vcpu
H_REGISTER_VPA Register a virtual processor area (VPA)
The code that runs in real mode has to be in the base kernel, not in
the module, if KVM is compiled as a module. The real-mode code can
only access the kernel linear mapping, not vmalloc or ioremap space.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds support for KVM running on 64-bit Book 3S processors,
specifically POWER7, in hypervisor mode. Using hypervisor mode means
that the guest can use the processor's supervisor mode. That means
that the guest can execute privileged instructions and access privileged
registers itself without trapping to the host. This gives excellent
performance, but does mean that KVM cannot emulate a processor
architecture other than the one that the hardware implements.
This code assumes that the guest is running paravirtualized using the
PAPR (Power Architecture Platform Requirements) interface, which is the
interface that IBM's PowerVM hypervisor uses. That means that existing
Linux distributions that run on IBM pSeries machines will also run
under KVM without modification. In order to communicate the PAPR
hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code
to include/linux/kvm.h.
Currently the choice between book3s_hv support and book3s_pr support
(i.e. the existing code, which runs the guest in user mode) has to be
made at kernel configuration time, so a given kernel binary can only
do one or the other.
This new book3s_hv code doesn't support MMIO emulation at present.
Since we are running paravirtualized guests, this isn't a serious
restriction.
With the guest running in supervisor mode, most exceptions go straight
to the guest. We will never get data or instruction storage or segment
interrupts, alignment interrupts, decrementer interrupts, program
interrupts, single-step interrupts, etc., coming to the hypervisor from
the guest. Therefore this introduces a new KVMTEST_NONHV macro for the
exception entry path so that we don't have to do the KVM test on entry
to those exception handlers.
We do however get hypervisor decrementer, hypervisor data storage,
hypervisor instruction storage, and hypervisor emulation assist
interrupts, so we have to handle those.
In hypervisor mode, real-mode accesses can access all of RAM, not just
a limited amount. Therefore we put all the guest state in the vcpu.arch
and use the shadow_vcpu in the PACA only for temporary scratch space.
We allocate the vcpu with kzalloc rather than vzalloc, and we don't use
anything in the kvmppc_vcpu_book3s struct, so we don't allocate it.
We don't have a shared page with the guest, but we still need a
kvm_vcpu_arch_shared struct to store the values of various registers,
so we include one in the vcpu_arch struct.
The POWER7 processor has a restriction that all threads in a core have
to be in the same partition. MMU-on kernel code counts as a partition
(partition 0), so we have to do a partition switch on every entry to and
exit from the guest. At present we require the host and guest to run
in single-thread mode because of this hardware restriction.
This code allocates a hashed page table for the guest and initializes
it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We
require that the guest memory is allocated using 16MB huge pages, in
order to simplify the low-level memory management. This also means that
we can get away without tracking paging activity in the host for now,
since huge pages can't be paged or swapped.
This also adds a few new exports needed by the book3s_hv code.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
There are several fields in struct kvmppc_book3s_shadow_vcpu that
temporarily store bits of host state while a guest is running,
rather than anything relating to the particular guest or vcpu.
This splits them out into a new kvmppc_host_state structure and
modifies the definitions in asm-offsets.c to suit.
On 32-bit, we have a kvmppc_host_state structure inside the
kvmppc_book3s_shadow_vcpu since the assembly code needs to be able
to get to them both with one pointer. On 64-bit they are separate
fields in the PACA. This means that on 64-bit we don't need to
copy the kvmppc_host_state in and out on vcpu load/unload, and
in future will mean that the book3s_hv code doesn't need a
shadow_vcpu struct in the PACA at all. That does mean that we
have to be careful not to rely on any values persisting in the
hstate field of the paca across any point where we could block
or get preempted.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Dynamically assign host PIDs to guest PIDs, splitting each guest PID into
multiple host (shadow) PIDs based on kernel/user and MSR[IS/DS]. Use
both PID0 and PID1 so that the shadow PIDs for the right mode can be
selected, that correspond both to guest TID = zero and guest TID = guest
PID.
This allows us to significantly reduce the frequency of needing to
invalidate the entire TLB. When the guest mode or PID changes, we just
update the host PID0/PID1. And since the allocation of shadow PIDs is
global, multiple guests can share the TLB without conflict.
Note that KVM does not yet support the guest setting PID1 or PID2 to
a value other than zero. This will need to be fixed for nested KVM
to work. Until then, we enforce the requirement for guest PID1/PID2
to stay zero by failing the emulation if the guest tries to set them
to something else.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This is done lazily. The SPE save will be done only if the guest has
used SPE since the last preemption or heavyweight exit. Restore will be
done only on demand, when enabling MSR_SPE in the shadow MSR, in response
to an SPE fault or mtmsr emulation.
For SPEFSCR, Linux already switches it on context switch (non-lazily), so
the only remaining bit is to save it between qemu and the guest.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Keep the guest MSR and the guest-mode true MSR separate, rather than
modifying the guest MSR on each guest entry to produce a true MSR.
Any bits which should be modified based on guest MSR must be explicitly
propagated from vcpu->arch.shared->msr to vcpu->arch.shadow_msr in
kvmppc_set_msr().
While we're modifying the guest entry code, reorder a few instructions
to bury some load latencies.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
We expect this is actually faster, and we end up needing more space than we
can get from the SPRGs in some instances. This is also useful when running
as a guest OS - SPRGs4-7 do not have guest versions.
8 slots are allocated in thread_info for this even though we only actually
use 4 of them - this allows space for future code to have more scratch
space (and we know we'll need it for things like hugetlb).
Signed-off-by: Ashish Kalra <Ashish.Kalra@freescale.com>
Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
* 'kvm-updates/2.6.40' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (131 commits)
KVM: MMU: Use ptep_user for cmpxchg_gpte()
KVM: Fix kvm mmu_notifier initialization order
KVM: Add documentation for KVM_CAP_NR_VCPUS
KVM: make guest mode entry to be rcu quiescent state
KVM: x86 emulator: Make jmp far emulation into a separate function
KVM: x86 emulator: Rename emulate_grpX() to em_grpX()
KVM: x86 emulator: Remove unused arg from emulate_pop()
KVM: x86 emulator: Remove unused arg from writeback()
KVM: x86 emulator: Remove unused arg from read_descriptor()
KVM: x86 emulator: Remove unused arg from seg_override()
KVM: Validate userspace_addr of memslot when registered
KVM: MMU: Clean up gpte reading with copy_from_user()
KVM: PPC: booke: add sregs support
KVM: PPC: booke: save/restore VRSAVE (a.k.a. USPRG0)
KVM: PPC: use ticks, not usecs, for exit timing
KVM: PPC: fix exit accounting for SPRs, tlbwe, tlbsx
KVM: PPC: e500: emulate SVR
KVM: VMX: Cache vmcs segment fields
KVM: x86 emulator: consolidate segment accessors
KVM: VMX: Avoid reading %rip unnecessarily when handling exceptions
...
Linux doesn't use USPRG0 (now renamed VRSAVE in the architecture, even
when Altivec isn't involved), but a guest might.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
The DSCR (aka Data Stream Control Register) is supported on some
server PowerPC chips and allow some control over the prefetch
of data streams.
This patch allows the value to be specified per thread by emulating
the corresponding mfspr and mtspr instructions. Children of such
threads inherit the value. Other threads use a default value that
can be specified in sysfs - /sys/devices/system/cpu/dscr_default.
If a thread starts with non default value in the sysfs entry,
all children threads inherit this non default value even if
the sysfs value is changed later.
Signed-off-by: Alexey Kardashevskiy <aik@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Since STACK_FRAME_OVERHEAD is defined in asm/ptrace.h and that
is ASSEMBER safe, we can just include that instead of going via
asm-offsets.h.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* 'kvm-updates/2.6.37' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (321 commits)
KVM: Drop CONFIG_DMAR dependency around kvm_iommu_map_pages
KVM: Fix signature of kvm_iommu_map_pages stub
KVM: MCE: Send SRAR SIGBUS directly
KVM: MCE: Add MCG_SER_P into KVM_MCE_CAP_SUPPORTED
KVM: fix typo in copyright notice
KVM: Disable interrupts around get_kernel_ns()
KVM: MMU: Avoid sign extension in mmu_alloc_direct_roots() pae root address
KVM: MMU: move access code parsing to FNAME(walk_addr) function
KVM: MMU: audit: check whether have unsync sps after root sync
KVM: MMU: audit: introduce audit_printk to cleanup audit code
KVM: MMU: audit: unregister audit tracepoints before module unloaded
KVM: MMU: audit: fix vcpu's spte walking
KVM: MMU: set access bit for direct mapping
KVM: MMU: cleanup for error mask set while walk guest page table
KVM: MMU: update 'root_hpa' out of loop in PAE shadow path
KVM: x86 emulator: Eliminate compilation warning in x86_decode_insn()
KVM: x86: Fix constant type in kvm_get_time_scale
KVM: VMX: Add AX to list of registers clobbered by guest switch
KVM guest: Move a printk that's using the clock before it's ready
KVM: x86: TSC catchup mode
...
This is the guest side of the mtsr acceleration. Using this a guest can now
call mtsrin with almost no overhead as long as it ensures that it only uses
it with (MSR_IR|MSR_DR) == 0. Linux does that, so we're good.
Signed-off-by: Alexander Graf <agraf@suse.de>
When CONFIG_KVM_GUEST is selected, but CONFIG_KVM is not, we were missing
some defines in asm-offsets.c and included too many headers at other places.
This patch makes above configuration work.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
We have all the hypervisor pieces in place now, but the guest parts are still
missing.
This patch implements basic awareness of KVM when running Linux as guest. It
doesn't do anything with it yet though.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
One of the most obvious registers to share with the guest directly is the
MSR. The MSR contains the "interrupts enabled" flag which the guest has to
toggle in critical sections.
So in order to bring the overhead of interrupt en- and disabling down, let's
put msr into the shared page. Keep in mind that even though you can fully read
its contents, writing to it doesn't always update all state. There are a few
safe fields that don't require hypervisor interaction. See the documentation
for a list of MSR bits that are safe to be set from inside the guest.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
For transparent variable sharing between the hypervisor and guest, I introduce
a shared page. This shared page will contain all the registers the guest can
read and write safely without exiting guest context.
This patch only implements the stubs required for the basic structure of the
shared page. The actual register moving follows.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
On Freescale parts typically have TLB array for large mappings that we can
bolt the linear mapping into. We utilize the code that already exists
on PPC32 on the 64-bit side to setup the linear mapping to be cover by
bolted TLB entries. We utilize a quarter of the variable size TLB array
for this purpose.
Additionally, we limit the amount of memory to what we can cover via
bolted entries so we don't get secondary faults in the TLB miss
handlers. We should fix this limitation in the future.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the
PURR register for measuring the user and system time used by
processes, as well as other related times such as hardirq and
softirq times. This turns out to be quite confusing for users
because it means that a program will often be measured as taking
less time when run on a multi-threaded processor (SMT2 or SMT4 mode)
than it does when run on a single-threaded processor (ST mode), even
though the program takes longer to finish. The discrepancy is
accounted for as stolen time, which is also confusing, particularly
when there are no other partitions running.
This changes the accounting to use the timebase instead, meaning that
the reported user and system times are the actual number of real-time
seconds that the program was executing on the processor thread,
regardless of which SMT mode the processor is in. Thus a program will
generally show greater user and system times when run on a
multi-threaded processor than on a single-threaded processor.
On pSeries systems on POWER5 or later processors, we measure the
stolen time (time when this partition wasn't running) using the
hypervisor dispatch trace log. We check for new entries in the
log on every entry from user mode and on every transition from
kernel process context to soft or hard IRQ context (i.e. when
account_system_vtime() gets called). So that we can correctly
distinguish time stolen from user time and time stolen from system
time, without having to check the log on every exit to user mode,
we store separate timestamps for exit to user mode and entry from
user mode.
On systems that have a SPURR (POWER6 and POWER7), we read the SPURR
in account_system_vtime() (as before), and then apportion the SPURR
ticks since the last time we read it between scaled user time and
scaled system time according to the relative proportions of user
time and system time over the same interval. This avoids having to
read the SPURR on every kernel entry and exit. On systems that have
PURR but not SPURR (i.e., POWER5), we do the same using the PURR
rather than the SPURR.
This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl
for now since it conflicts with the use of the dispatch trace log
by the time accounting code.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Now we dynamically allocate the paca array, it takes an extra load
whenever we want to access another cpu's paca. One place we do that a lot
is per cpu variables. A simple example:
DEFINE_PER_CPU(unsigned long, vara);
unsigned long test4(int cpu)
{
return per_cpu(vara, cpu);
}
This takes 4 loads, 5 if you include the actual load of the per cpu variable:
ld r11,-32760(r30) # load address of paca pointer
ld r9,-32768(r30) # load link address of percpu variable
sldi r3,r29,9 # get offset into paca (each entry is 512 bytes)
ld r0,0(r11) # load paca pointer
add r3,r0,r3 # paca + offset
ld r11,64(r3) # load paca[cpu].data_offset
ldx r3,r9,r11 # load per cpu variable
If we remove the ppc64 specific per_cpu_offset(), we get the generic one
which indexes into a statically allocated array. This removes one load and
one add:
ld r11,-32760(r30) # load address of __per_cpu_offset
ld r9,-32768(r30) # load link address of percpu variable
sldi r3,r29,3 # get offset into __per_cpu_offset (each entry 8 bytes)
ldx r11,r11,r3 # load __per_cpu_offset[cpu]
ldx r3,r9,r11 # load per cpu variable
Having all the offsets in one array also helps when iterating over a per cpu
variable across a number of cpus, such as in the scheduler. Before we would
need to load one paca cacheline when calculating each per cpu offset. Now we
have 16 (128 / sizeof(long)) per cpu offsets in each cacheline.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Currently it is possible for userspace to see the result of
gettimeofday() going backwards by 1 microsecond, assuming that
userspace is using the gettimeofday() in the VDSO. The VDSO
gettimeofday() algorithm computes the time in "xsecs", which are
units of 2^-20 seconds, or approximately 0.954 microseconds,
using the algorithm
now = (timebase - tb_orig_stamp) * tb_to_xs + stamp_xsec
and then converts the time in xsecs to seconds and microseconds.
The kernel updates the tb_orig_stamp and stamp_xsec values every
tick in update_vsyscall(). If the length of the tick is not an
integer number of xsecs, then some precision is lost in converting
the current time to xsecs. For example, with CONFIG_HZ=1000, the
tick is 1ms long, which is 1048.576 xsecs. That means that
stamp_xsec will advance by either 1048 or 1049 on each tick.
With the right conditions, it is possible for userspace to get
(timebase - tb_orig_stamp) * tb_to_xs being 1049 if the kernel is
slightly late in updating the vdso_datapage, and then for stamp_xsec
to advance by 1048 when the kernel does update it, and for userspace
to then see (timebase - tb_orig_stamp) * tb_to_xs being zero due to
integer truncation. The result is that time appears to go backwards
by 1 microsecond.
To fix this we change the VDSO gettimeofday to use a new field in the
VDSO datapage which stores the nanoseconds part of the time as a
fractional number of seconds in a 0.32 binary fraction format.
(Or put another way, as a 32-bit number in units of 0.23283 ns.)
This is convenient because we can use the mulhwu instruction to
convert it to either microseconds or nanoseconds.
Since it turns out that computing the time of day using this new field
is simpler than either using stamp_xsec (as gettimeofday does) or
stamp_xtime.tv_nsec (as clock_gettime does), this converts both
gettimeofday and clock_gettime to use the new field. The existing
__do_get_tspec function is converted to use the new field and take
a parameter in r7 that indicates the desired resolution, 1,000,000
for microseconds or 1,000,000,000 for nanoseconds. The __do_get_xsec
function is then unused and is deleted.
The new algorithm is
now = ((timebase - tb_orig_stamp) << 12) * tb_to_xs
+ (stamp_xtime_seconds << 32) + stamp_sec_fraction
with 'now' in units of 2^-32 seconds. That is then converted to
seconds and either microseconds or nanoseconds with
seconds = now >> 32
partseconds = ((now & 0xffffffff) * resolution) >> 32
The 32-bit VDSO code also makes a further simplification: it ignores
the bottom 32 bits of the tb_to_xs value, which is a 0.64 format binary
fraction. Doing so gets rid of 4 multiply instructions. Assuming
a timebase frequency of 1GHz or less and an update interval of no
more than 10ms, the upper 32 bits of tb_to_xs will be at least
4503599, so the error from ignoring the low 32 bits will be at most
2.2ns, which is more than an order of magnitude less than the time
taken to do gettimeofday or clock_gettime on our fastest processors,
so there is no possibility of seeing inconsistent values due to this.
This also moves update_gtod() down next to its only caller, and makes
update_vsyscall use the time passed in via the wall_time argument rather
than accessing xtime directly. At present, wall_time always points to
xtime, but that could change in future.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* 'kvm-updates/2.6.35' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (269 commits)
KVM: x86: Add missing locking to arch specific vcpu ioctls
KVM: PPC: Add missing vcpu_load()/vcpu_put() in vcpu ioctls
KVM: MMU: Segregate shadow pages with different cr0.wp
KVM: x86: Check LMA bit before set_efer
KVM: Don't allow lmsw to clear cr0.pe
KVM: Add cpuid.txt file
KVM: x86: Tell the guest we'll warn it about tsc stability
x86, paravirt: don't compute pvclock adjustments if we trust the tsc
x86: KVM guest: Try using new kvm clock msrs
KVM: x86: export paravirtual cpuid flags in KVM_GET_SUPPORTED_CPUID
KVM: x86: add new KVMCLOCK cpuid feature
KVM: x86: change msr numbers for kvmclock
x86, paravirt: Add a global synchronization point for pvclock
x86, paravirt: Enable pvclock flags in vcpu_time_info structure
KVM: x86: Inject #GP with the right rip on efer writes
KVM: SVM: Don't allow nested guest to VMMCALL into host
KVM: x86: Fix exception reinjection forced to true
KVM: Fix wallclock version writing race
KVM: MMU: Don't read pdptrs with mmu spinlock held in mmu_alloc_roots
KVM: VMX: enable VMXON check with SMX enabled (Intel TXT)
...
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (92 commits)
powerpc: Remove unused 'protect4gb' boot parameter
powerpc: Build-in e1000e for pseries & ppc64_defconfig
powerpc/pseries: Make request_ras_irqs() available to other pseries code
powerpc/numa: Use ibm,architecture-vec-5 to detect form 1 affinity
powerpc/numa: Set a smaller value for RECLAIM_DISTANCE to enable zone reclaim
powerpc: Use smt_snooze_delay=-1 to always busy loop
powerpc: Remove check of ibm,smt-snooze-delay OF property
powerpc/kdump: Fix race in kdump shutdown
powerpc/kexec: Fix race in kexec shutdown
powerpc/kexec: Speedup kexec hash PTE tear down
powerpc/pseries: Add hcall to read 4 ptes at a time in real mode
powerpc: Use more accurate limit for first segment memory allocations
powerpc/kdump: Use chip->shutdown to disable IRQs
powerpc/kdump: CPUs assume the context of the oopsing CPU
powerpc/crashdump: Do not fail on NULL pointer dereferencing
powerpc/eeh: Fix oops when probing in early boot
powerpc/pci: Check devices status property when scanning OF tree
powerpc/vio: Switch VIO Bus PM to use generic helpers
powerpc: Avoid bad relocations in iSeries code
powerpc: Use common cpu_die (fixes SMP+SUSPEND build)
...
In kexec_prepare_cpus, the primary CPU IPIs the secondary CPUs to
kexec_smp_down(). kexec_smp_down() calls kexec_smp_wait() which sets
the hw_cpu_id() to -1. The primary does this while leaving IRQs on
which means the primary can take a timer interrupt which can lead to
the IPIing one of the secondary CPUs (say, for a scheduler re-balance)
but since the secondary CPU now has a hw_cpu_id = -1, we IPI CPU
-1... Kaboom!
We are hitting this case regularly on POWER7 machines.
There is also a second race, where the primary will tear down the MMU
mappings before knowing the secondaries have entered real mode.
Also, the secondaries are clearing out any pending IPIs before
guaranteeing that no more will be received.
This changes kexec_prepare_cpus() so that we turn off IRQs in the
primary CPU much earlier. It adds a paca flag to say that the
secondaries have entered the kexec_smp_down() IPI and turned off IRQs,
rather than overloading hw_cpu_id with -1. This new paca flag is
again used to in indicate when the secondaries has entered real mode.
It also ensures that all CPUs have their IRQs off before we clear out
any pending IPI requests (in kexec_cpu_down()) to ensure there are no
trailing IPIs left unacknowledged.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When we build with ftrace enabled its possible that loadcam_entry would
have used the stack pointer (even though the code doesn't need it). We
call loadcam_entry in __secondary_start before the stack is setup. To
ensure that loadcam_entry doesn't use the stack pointer the easiest
solution is to just have it in asm code.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
We need the SWITCH_FRAME_SIZE define on Book3S_32 now too.
So let's export it unconditionally.
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
We need to keep the pointer to the shadow vcpu somewhere accessible from
within really early interrupt code. The best fit I found was the thread
struct, as that resides in an SPRG.
So let's put a pointer to the shadow vcpu in the thread struct and add
an asm-offset so we can find it.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
The shadow vcpu now contains some fields we don't use from the vcpu anymore.
Access to them happens using inline functions that happily use the shadow
vcpu fields.
So let's now ifdef them out to booke only and add asm-offsets.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Upstream recently added a new name for PPC64: Book3S_64.
So instead of using CONFIG_PPC64 we should use CONFIG_PPC_BOOK3S consotently.
That makes understanding the code easier (I hope).
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Anton Blanchard found that large POWER systems would occasionally
crash in the exception exit path when profiling with perf_events.
The symptom was that an interrupt would occur late in the exit path
when the MSR[RI] (recoverable interrupt) bit was clear. Interrupts
should be hard-disabled at this point but they were enabled. Because
the interrupt was not recoverable the system panicked.
The reason is that the exception exit path was calling
perf_event_do_pending after hard-disabling interrupts, and
perf_event_do_pending will re-enable interrupts.
The simplest and cleanest fix for this is to use the same mechanism
that 32-bit powerpc does, namely to cause a self-IPI by setting the
decrementer to 1. This means we can remove the tests in the exception
exit path and raw_local_irq_restore.
This also makes sure that the call to perf_event_do_pending from
timer_interrupt() happens within irq_enter/irq_exit. (Note that
calling perf_event_do_pending from timer_interrupt does not mean that
there is a possible 1/HZ latency; setting the decrementer to 1 ensures
that the timer interrupt will happen immediately, i.e. within one
timebase tick, which is a few nanoseconds or 10s of nanoseconds.)
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: stable@kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
SRR1 stores more information that just the MSR value. It also stores
valuable information about the type of interrupt we received, for
example whether the storage interrupt we just got was because of a
missing htab entry or not.
We use that information to speed up the exit path.
Now if we get preempted before we can interpret the shadow_msr values,
we get into vcpu_put which then calls the MSR handler, which then sets
all the SRR1 information bits in shadow_msr to 0. Great.
So let's preserve the SRR1 specific bits in shadow_msr whenever we set
the MSR. They don't hurt.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Currently we're racy when doing the transition from IR=1 to IR=0, from
the module memory entry code to the real mode SLB switching code.
To work around that I took a look at the RTAS entry code which is faced
with a similar problem and did the same thing:
A small helper in linear mapped memory that does mtmsr with IR=0 and
then RFIs info the actual handler.
Thanks to that trick we can safely take page faults in the entry code
and only need to be really wary of what to do as of the SLB switching
part.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
We're being horribly racy right now. All the entry and exit code hijacks
random fields from the PACA that could easily be used by different code in
case we get interrupted, for example by a #MC or even page fault.
After discussing this with Ben, we figured it's best to reserve some more
space in the PACA and just shove off some vcpu state to there.
That way we can drastically improve the readability of the code, make it
less racy and less complex.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Re-write the code so its more standalone and fixed some issues:
* Bump'd # of CAM entries to 64 to support e500mc
* Make the code handle MAS7 properly
* Use pr_cont instead of creating a string as we go
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
In order to access fields in the PACA from assembly code, we need
to generate offsets using asm-offsets.c.
So let's add the new PACA related bits, we just introduced!
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We need to access some VCPU fields from assembly code. In order to get
the proper offsets, we have to define them in asm-offsets.c.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Bye-bye Performance Counters, welcome Performance Events!
In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.
Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.
All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)
The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.
Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.
User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)
This patch has been generated via the following script:
FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
sed -i \
-e 's/PERF_EVENT_/PERF_RECORD_/g' \
-e 's/PERF_COUNTER/PERF_EVENT/g' \
-e 's/perf_counter/perf_event/g' \
-e 's/nb_counters/nb_events/g' \
-e 's/swcounter/swevent/g' \
-e 's/tpcounter_event/tp_event/g' \
$FILES
for N in $(find . -name perf_counter.[ch]); do
M=$(echo $N | sed 's/perf_counter/perf_event/g')
mv $N $M
done
FILES=$(find . -name perf_event.*)
sed -i \
-e 's/COUNTER_MASK/REG_MASK/g' \
-e 's/COUNTER/EVENT/g' \
-e 's/\<event\>/event_id/g' \
-e 's/counter/event/g' \
-e 's/Counter/Event/g' \
$FILES
... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.
Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.
( NOTE: 'counters' are still the proper terminology when we deal
with hardware registers - and these sed scripts are a bit
over-eager in renaming them. I've undone some of that, but
in case there's something left where 'counter' would be
better than 'event' we can undo that on an individual basis
instead of touching an otherwise nicely automated patch. )
Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This adds various fields in the PACA that are for use specifically
by Book3E processors, such as exception save areas, current pgd
pointer, special exceptions kernel stacks etc...
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This adds the PTE and pgtable format definitions, along with changes
to the kernel memory map and other definitions related to implementing
support for 64-bit Book3E. This also shields some asm-offset bits that
are currently only relevant on 32-bit
We also move the definition of the "linux" page size constants to
the common mmu.h file and add a few sizes that are relevant to
embedded processors.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This provides a mechanism to allow the perf_counters code to access
user memory in a PMU interrupt routine. Such an access can cause
various kinds of interrupt: SLB miss, MMU hash table miss, segment
table miss, or TLB miss, depending on the processor. This commit
only deals with 64-bit classic/server processors, which use an MMU
hash table. 32-bit processors are already able to access user memory
at interrupt time. Since we don't soft-disable on 32-bit, we avoid
the possibility of reentering hash_page or the TLB miss handlers,
since they run with interrupts disabled.
On 64-bit processors, an SLB miss interrupt on a user address will
update the slb_cache and slb_cache_ptr fields in the paca. This is
OK except in the case where a PMU interrupt occurs in switch_slb,
which also accesses those fields. To prevent this, we hard-disable
interrupts in switch_slb. Interrupts are already soft-disabled at
this point, and will get hard-enabled when they get soft-enabled
later.
This also reworks slb_flush_and_rebolt: to avoid hard-disabling twice,
and to make sure that it clears the slb_cache_ptr when called from
other callers than switch_slb, the existing routine is renamed to
__slb_flush_and_rebolt, which is called by switch_slb and the new
version of slb_flush_and_rebolt.
Similarly, switch_stab (used on POWER3 and RS64 processors) gets a
hard_irq_disable() to protect the per-cpu variables used there and
in ste_allocate.
If a MMU hashtable miss interrupt occurs, normally we would call
hash_page to look up the Linux PTE for the address and create a HPTE.
However, hash_page is fairly complex and takes some locks, so to
avoid the possibility of deadlock, we check the preemption count
to see if we are in a (pseudo-)NMI handler, and if so, we don't call
hash_page but instead treat it like a bad access that will get
reported up through the exception table mechanism. An interrupt
whose handler runs even though the interrupt occurred when
soft-disabled (such as the PMU interrupt) is considered a pseudo-NMI
handler, which should use nmi_enter()/nmi_exit() rather than
irq_enter()/irq_exit().
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch has no effect other than re-ordering PACA fields on
current server CPUs. It however is a pre-requisite for future
support of BookE 64-bit processors. Various parts of the PACA
struct are now moved under some ifdef's, either the new
CONFIG_PPC_BOOK3S or CONFIG_PPC_STD_MMU_64, whatever seems more
appropriate.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.craashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Merge reason: we have gathered quite a few conflicts, need to merge upstream
Conflicts:
arch/powerpc/kernel/Makefile
arch/x86/ia32/ia32entry.S
arch/x86/include/asm/hardirq.h
arch/x86/include/asm/unistd_32.h
arch/x86/include/asm/unistd_64.h
arch/x86/kernel/cpu/common.c
arch/x86/kernel/irq.c
arch/x86/kernel/syscall_table_32.S
arch/x86/mm/iomap_32.c
include/linux/sched.h
kernel/Makefile
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Michael Neuling