When it was introduced, zone_reclaim_mode made sense as NUMA distances
punished and workloads were generally partitioned to fit into a NUMA
node. NUMA machines are now common but few of the workloads are
NUMA-aware and it's routine to see major performance degradation due to
zone_reclaim_mode being enabled but relatively few can identify the
problem.
Those that require zone_reclaim_mode are likely to be able to detect
when it needs to be enabled and tune appropriately so lets have a
sensible default for the bulk of users.
This patch (of 2):
zone_reclaim_mode causes processes to prefer reclaiming memory from
local node instead of spilling over to other nodes. This made sense
initially when NUMA machines were almost exclusively HPC and the
workload was partitioned into nodes. The NUMA penalties were
sufficiently high to justify reclaiming the memory. On current machines
and workloads it is often the case that zone_reclaim_mode destroys
performance but not all users know how to detect this. Favour the
common case and disable it by default. Users that are sophisticated
enough to know they need zone_reclaim_mode will detect it.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
_PAGE_NUMA is currently an alias of _PROT_PROTNONE to trap NUMA hinting
faults on x86. Care is taken such that _PAGE_NUMA is used only in
situations where the VMA flags distinguish between NUMA hinting faults
and prot_none faults. This decision was x86-specific and conceptually
it is difficult requiring special casing to distinguish between PROTNONE
and NUMA ptes based on context.
Fundamentally, we only need the _PAGE_NUMA bit to tell the difference
between an entry that is really unmapped and a page that is protected
for NUMA hinting faults as if the PTE is not present then a fault will
be trapped.
Swap PTEs on x86-64 use the bits after _PAGE_GLOBAL for the offset.
This patch shrinks the maximum possible swap size and uses the bit to
uniquely distinguish between NUMA hinting ptes and swap ptes.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently hugepage migration is available for all archs which support
pmd-level hugepage, but testing is done only for x86_64 and there're
bugs for other archs. So to avoid breaking such archs, this patch
limits the availability strictly to x86_64 until developers of other
archs get interested in enabling this feature.
Simply disabling hugepage migration on non-x86_64 archs is not enough to
fix the reported problem where sys_move_pages() hits the BUG_ON() in
follow_page(FOLL_GET), so let's fix this by checking if hugepage
migration is supported in vma_migratable().
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: <stable@vger.kernel.org> [3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Another round of clean-up of FDT related code in architecture code.
This removes knowledge of internal FDT details from most architectures
except powerpc.
- Conversion of kernel's custom FDT parsing code to use libfdt.
- DT based initialization for generic serial earlycon. The introduction
of generic serial earlycon support went in thru tty tree.
- Improve the platform device naming for DT probed devices to ensure
unique naming and use parent names instead of a global index.
- Fix a race condition in of_update_property.
- Unify the various linker section OF match tables and fix several
function prototype errors.
- Update platform_get_irq_byname to work in deferred probe cases.
- 2 binding doc updates
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Merge tag 'devicetree-for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux into next
Pull DeviceTree updates from Rob Herring:
- Another round of clean-up of FDT related code in architecture code.
This removes knowledge of internal FDT details from most
architectures except powerpc.
- Conversion of kernel's custom FDT parsing code to use libfdt.
- DT based initialization for generic serial earlycon. The
introduction of generic serial earlycon support went in through the
tty tree.
- Improve the platform device naming for DT probed devices to ensure
unique naming and use parent names instead of a global index.
- Fix a race condition in of_update_property.
- Unify the various linker section OF match tables and fix several
function prototype errors.
- Update platform_get_irq_byname to work in deferred probe cases.
- 2 binding doc updates
* tag 'devicetree-for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (58 commits)
of: handle NULL node in next_child iterators
of/irq: provide more wrappers for !CONFIG_OF
devicetree: bindings: Document micrel vendor prefix
dt: bindings: dwc2: fix required value for the phy-names property
of_pci_irq: kill useless variable in of_irq_parse_pci()
of/irq: do irq resolution in platform_get_irq_byname()
of: Add a testcase for of_find_node_by_path()
of: Make of_find_node_by_path() handle /aliases
of: Create unlocked version of for_each_child_of_node()
lib: add glibc style strchrnul() variant
of: Handle memory@0 node on PPC32 only
pci/of: Remove dead code
of: fix race between search and remove in of_update_property()
of: Use NULL for pointers
of: Stop naming platform_device using dcr address
of: Ensure unique names without sacrificing determinism
tty/serial: pl011: add DT based earlycon support
of/fdt: add FDT serial scanning for earlycon
of/fdt: add FDT address translation support
serial: earlycon: add DT support
...
was a pretty active cycle for KVM. Changes include:
- a lot of s390 changes: optimizations, support for migration,
GDB support and more
- ARM changes are pretty small: support for the PSCI 0.2 hypercall
interface on both the guest and the host (the latter acked by Catalin)
- initial POWER8 and little-endian host support
- support for running u-boot on embedded POWER targets
- pretty large changes to MIPS too, completing the userspace interface
and improving the handling of virtualized timer hardware
- for x86, a larger set of changes is scheduled for 3.17. Still,
we have a few emulator bugfixes and support for running nested
fully-virtualized Xen guests (para-virtualized Xen guests have
always worked). And some optimizations too.
The only missing architecture here is ia64. It's not a coincidence
that support for KVM on ia64 is scheduled for removal in 3.17.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm into next
Pull KVM updates from Paolo Bonzini:
"At over 200 commits, covering almost all supported architectures, this
was a pretty active cycle for KVM. Changes include:
- a lot of s390 changes: optimizations, support for migration, GDB
support and more
- ARM changes are pretty small: support for the PSCI 0.2 hypercall
interface on both the guest and the host (the latter acked by
Catalin)
- initial POWER8 and little-endian host support
- support for running u-boot on embedded POWER targets
- pretty large changes to MIPS too, completing the userspace
interface and improving the handling of virtualized timer hardware
- for x86, a larger set of changes is scheduled for 3.17. Still, we
have a few emulator bugfixes and support for running nested
fully-virtualized Xen guests (para-virtualized Xen guests have
always worked). And some optimizations too.
The only missing architecture here is ia64. It's not a coincidence
that support for KVM on ia64 is scheduled for removal in 3.17"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (203 commits)
KVM: add missing cleanup_srcu_struct
KVM: PPC: Book3S PR: Rework SLB switching code
KVM: PPC: Book3S PR: Use SLB entry 0
KVM: PPC: Book3S HV: Fix machine check delivery to guest
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs
KVM: PPC: Book3S HV: Make sure we don't miss dirty pages
KVM: PPC: Book3S HV: Fix dirty map for hugepages
KVM: PPC: Book3S HV: Put huge-page HPTEs in rmap chain for base address
KVM: PPC: Book3S HV: Fix check for running inside guest in global_invalidates()
KVM: PPC: Book3S: Move KVM_REG_PPC_WORT to an unused register number
KVM: PPC: Book3S: Add ONE_REG register names that were missed
KVM: PPC: Add CAP to indicate hcall fixes
KVM: PPC: MPIC: Reset IRQ source private members
KVM: PPC: Graciously fail broken LE hypercalls
PPC: ePAPR: Fix hypercall on LE guest
KVM: PPC: BOOK3S: Remove open coded make_dsisr in alignment handler
KVM: PPC: BOOK3S: Always use the saved DAR value
PPC: KVM: Make NX bit available with magic page
KVM: PPC: Disable NX for old magic page using guests
KVM: PPC: BOOK3S: HV: Add mixed page-size support for guest
...
Pull scheduler updates from Ingo Molnar:
"The main scheduling related changes in this cycle were:
- various sched/numa updates, for better performance
- tree wide cleanup of open coded nice levels
- nohz fix related to rq->nr_running use
- cpuidle changes and continued consolidation to improve the
kernel/sched/idle.c high level idle scheduling logic. As part of
this effort I pulled cpuidle driver changes from Rafael as well.
- standardized idle polling amongst architectures
- continued work on preparing better power/energy aware scheduling
- sched/rt updates
- misc fixlets and cleanups"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (49 commits)
sched/numa: Decay ->wakee_flips instead of zeroing
sched/numa: Update migrate_improves/degrades_locality()
sched/numa: Allow task switch if load imbalance improves
sched/rt: Fix 'struct sched_dl_entity' and dl_task_time() comments, to match the current upstream code
sched: Consolidate open coded implementations of nice level frobbing into nice_to_rlimit() and rlimit_to_nice()
sched: Initialize rq->age_stamp on processor start
sched, nohz: Change rq->nr_running to always use wrappers
sched: Fix the rq->next_balance logic in rebalance_domains() and idle_balance()
sched: Use clamp() and clamp_val() to make sys_nice() more readable
sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups()
sched/numa: Fix initialization of sched_domain_topology for NUMA
sched: Call select_idle_sibling() when not affine_sd
sched: Simplify return logic in sched_read_attr()
sched: Simplify return logic in sched_copy_attr()
sched: Fix exec_start/task_hot on migrated tasks
arm64: Remove TIF_POLLING_NRFLAG
metag: Remove TIF_POLLING_NRFLAG
sched/idle: Make cpuidle_idle_call() void
sched/idle: Reflow cpuidle_idle_call()
sched/idle: Delay clearing the polling bit
...
Here is the big USB driver pull request for 3.16-rc1.
Nothing huge here, but lots of little things in the USB core, and in
lots of drivers. Hopefully the USB power management will be work better
now that it has been reworked to do per-port power control dynamically.
There's also a raft of gadget driver updates and fixes, CONFIG_USB_DEBUG
is finally gone now that everything has been converted over to the
dynamic debug inteface, the last hold-out drivers were cleaned up and
the config option removed. There were also other minor things all
through the drivers/usb/ tree, the shortlog shows this pretty well.
All have been in linux-next, including the very last patch, which came
from linux-next to fix a build issue on some platforms.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'usb-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb into next
Pull USB driver updates from Greg KH:
"Here is the big USB driver pull request for 3.16-rc1.
Nothing huge here, but lots of little things in the USB core, and in
lots of drivers. Hopefully the USB power management will be work
better now that it has been reworked to do per-port power control
dynamically. There's also a raft of gadget driver updates and fixes,
CONFIG_USB_DEBUG is finally gone now that everything has been
converted over to the dynamic debug inteface, the last hold-out
drivers were cleaned up and the config option removed. There were
also other minor things all through the drivers/usb/ tree, the
shortlog shows this pretty well.
All have been in linux-next, including the very last patch, which came
from linux-next to fix a build issue on some platforms"
* tag 'usb-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (314 commits)
usb: hub_handle_remote_wakeup() only exists for CONFIG_PM=y
USB: orinoco_usb: remove CONFIG_USB_DEBUG support
USB: media: lirc: igorplugusb: remove CONFIG_USB_DEBUG support
USB: media: streamzap: remove CONFIG_USB_DEBUG
USB: media: redrat3: remove CONFIG_USB_DEBUG usage
USB: media: redrat3: remove unneeded tracing macro
usb: qcserial: add additional Sierra Wireless QMI devices
usb: host: max3421-hcd: Use module_spi_driver
usb: host: max3421-hcd: Allow platform-data to specify Vbus polarity
usb: host: max3421-hcd: fix "spi_rd8" uses dynamic stack allocation warning
usb: host: max3421-hcd: Fix missing unlock in max3421_urb_enqueue()
usb: qcserial: add Netgear AirCard 341U
Documentation: dt-bindings: update xhci-platform DT binding for R-Car H2 and M2
usb: host: xhci-plat: add xhci_plat_start()
usb: host: max3421-hcd: Fix potential NULL urb dereference
Revert "usb: gadget: net2280: Add support for PLX USB338X"
USB: usbip: remove CONFIG_USB_DEBUG reference
USB: remove CONFIG_USB_DEBUG from defconfig files
usb: resume child device when port is powered on
usb: hub_handle_remote_wakeup() depends on CONFIG_PM_RUNTIME=y
...
Pull powerpc fix from Ben Herrenschmidt:
"Here's just one trivial patch to wire up sys_renameat2 which I seem to
have completely missed so far.
(My test build scripts fwd me warnings but miss the ones generated for
missing syscalls)"
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc: Wire renameat2() syscall
On LPAR guest systems Linux enables the shadow SLB to indicate to the
hypervisor a number of SLB entries that always have to be available.
Today we go through this shadow SLB and disable all ESID's valid bits.
However, pHyp doesn't like this approach very much and honors us with
fancy machine checks.
Fortunately the shadow SLB descriptor also has an entry that indicates
the number of valid entries following. During the lifetime of a guest
we can just swap that value to 0 and don't have to worry about the
SLB restoration magic.
While we're touching the code, let's also make it more readable (get
rid of rldicl), allow it to deal with a dynamic number of bolted
SLB entries and only do shadow SLB swizzling on LPAR systems.
Signed-off-by: Alexander Graf <agraf@suse.de>
We didn't make use of SLB entry 0 because ... of no good reason. SLB entry 0
will always be used by the Linux linear SLB entry, so the fact that slbia
does not invalidate it doesn't matter as we overwrite SLB 0 on exit anyway.
Just enable use of SLB entry 0 for our shadow SLB code.
Signed-off-by: Alexander Graf <agraf@suse.de>
The code that delivered a machine check to the guest after handling
it in real mode failed to load up r11 before calling kvmppc_msr_interrupt,
which needs the old MSR value in r11 so it can see the transactional
state there. This adds the missing load.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds workarounds for two hardware bugs in the POWER8 performance
monitor unit (PMU), both related to interrupt generation. The effect
of these bugs is that PMU interrupts can get lost, leading to tools
such as perf reporting fewer counts and samples than they should.
The first bug relates to the PMAO (perf. mon. alert occurred) bit in
MMCR0; setting it should cause an interrupt, but doesn't. The other
bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0.
Setting PMAE when a counter is negative and counter negative
conditions are enabled to cause alerts should cause an alert, but
doesn't.
The workaround for the first bug is to create conditions where a
counter will overflow, whenever we are about to restore a MMCR0
value that has PMAO set (and PMAO_SYNC clear). The workaround for
the second bug is to freeze all counters using MMCR2 before reading
MMCR0.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Current, when testing whether a page is dirty (when constructing the
bitmap for the KVM_GET_DIRTY_LOG ioctl), we test the C (changed) bit
in the HPT entries mapping the page, and if it is 0, we consider the
page to be clean. However, the Power ISA doesn't require processors
to set the C bit to 1 immediately when writing to a page, and in fact
allows them to delay the writeback of the C bit until they receive a
TLB invalidation for the page. Thus it is possible that the page
could be dirty and we miss it.
Now, if there are vcpus running, this is not serious since the
collection of the dirty log is racy already - some vcpu could dirty
the page just after we check it. But if there are no vcpus running we
should return definitive results, in case we are in the final phase of
migrating the guest.
Also, if the permission bits in the HPTE don't allow writing, then we
know that no CPU can set C. If the HPTE was previously writable and
the page was modified, any C bit writeback would have been flushed out
by the tlbie that we did when changing the HPTE to read-only.
Otherwise we need to do a TLB invalidation even if the C bit is 0, and
then check the C bit.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
The dirty map that we construct for the KVM_GET_DIRTY_LOG ioctl has
one bit per system page (4K/64K). Currently, we only set one bit in
the map for each HPT entry with the Change bit set, even if the HPT is
for a large page (e.g., 16MB). Userspace then considers only the
first system page dirty, though in fact the guest may have modified
anywhere in the large page.
To fix this, we make kvm_test_clear_dirty() return the actual number
of pages that are dirty (and rename it to kvm_test_clear_dirty_npages()
to emphasize that that's what it returns). In kvmppc_hv_get_dirty_log()
we then set that many bits in the dirty map.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently, when a huge page is faulted in for a guest, we select the
rmap chain to insert the HPTE into based on the guest physical address
that the guest tried to access. Since there is an rmap chain for each
system page, there are many rmap chains for the area covered by a huge
page (e.g. 256 for 16MB pages when PAGE_SIZE = 64kB), and the huge-page
HPTE could end up in any one of them.
For consistency, and to make the huge-page HPTEs easier to find, we now
put huge-page HPTEs in the rmap chain corresponding to the base address
of the huge page.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
The global_invalidates() function contains a check that is intended
to tell whether we are currently executing in the context of a hypercall
issued by the guest. The reason is that the optimization of using a
local TLB invalidate instruction is only valid in that context. The
check was testing local_paca->kvm_hstate.kvm_vcore, which gets set
when entering the guest but no longer gets cleared when exiting the
guest. To fix this, we use the kvm_vcpu field instead, which does
get cleared when exiting the guest, by the kvmppc_release_hwthread()
calls inside kvmppc_run_core().
The effect of having the check wrong was that when kvmppc_do_h_remove()
got called from htab_write() on the destination machine during a
migration, it cleared the current cpu's bit in kvm->arch.need_tlb_flush.
This meant that when the guest started running in the destination VM,
it may miss out on doing a complete TLB flush, and therefore may end
up using stale TLB entries from a previous guest that used the same
LPID value.
This should make migration more reliable.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Commit b005255e12 ("KVM: PPC: Book3S HV: Context-switch new POWER8
SPRs") added a definition of KVM_REG_PPC_WORT with the same register
number as the existing KVM_REG_PPC_VRSAVE (though in fact the
definitions are not identical because of the different register sizes.)
For clarity, this moves KVM_REG_PPC_WORT to the next unused number,
and also adds it to api.txt.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
We worked around some nasty KVM magic page hcall breakages:
1) NX bit not honored, so ignore NX when we detect it
2) LE guests swizzle hypercall instruction
Without these fixes in place, there's no way it would make sense to expose kvm
hypercalls to a guest. Chances are immensely high it would trip over and break.
So add a new CAP that gives user space a hint that we have workarounds for the
bugs above in place. It can use those as hint to disable PV hypercalls when
the guest CPU is anything POWER7 or higher and the host does not have fixes
in place.
Signed-off-by: Alexander Graf <agraf@suse.de>
When we reset the in-kernel MPIC controller, we forget to reset some hidden
state such as destmask and output. This state is usually set when the guest
writes to the IDR register for a specific IRQ line.
To make sure we stay in sync and don't forget hidden state, treat reset of
the IDR register as a simple write of the IDR register. That automatically
updates all the hidden state as well.
Reported-by: Paul Janzen <pcj@pauljanzen.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
There are LE Linux guests out there that don't handle hypercalls correctly.
Instead of interpreting the instruction stream from device tree as big endian
they assume it's a little endian instruction stream and fail.
When we see an illegal instruction from such a byte reversed instruction stream,
bail out graciously and just declare every hcall as error.
Signed-off-by: Alexander Graf <agraf@suse.de>
We get an array of instructions from the hypervisor via device tree that
we write into a buffer that gets executed whenever we want to make an
ePAPR compliant hypercall.
However, the hypervisor passes us these instructions in BE order which
we have to manually convert to LE when we want to run them in LE mode.
With this fixup in place, I can successfully run LE kernels with KVM
PV enabled on PR KVM.
Signed-off-by: Alexander Graf <agraf@suse.de>
Use make_dsisr instead of open coding it. This also have
the added benefit of handling alignment interrupt on additional
instructions.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Although it's optional, IBM POWER cpus always had DAR value set on
alignment interrupt. So don't try to compute these values.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Because old kernels enable the magic page and then choke on NXed trampoline
code we have to disable NX by default in KVM when we use the magic page.
However, since commit b18db0b8 we have successfully fixed that and can now
leave NX enabled, so tell the hypervisor about this.
Signed-off-by: Alexander Graf <agraf@suse.de>
Old guests try to use the magic page, but map their trampoline code inside
of an NX region.
Since we can't fix those old kernels, try to detect whether the guest is sane
or not. If not, just disable NX functionality in KVM so that old guests at
least work at all. For newer guests, add a bit that we can set to keep NX
functionality available.
Signed-off-by: Alexander Graf <agraf@suse.de>
On recent IBM Power CPUs, while the hashed page table is looked up using
the page size from the segmentation hardware (i.e. the SLB), it is
possible to have the HPT entry indicate a larger page size. Thus for
example it is possible to put a 16MB page in a 64kB segment, but since
the hash lookup is done using a 64kB page size, it may be necessary to
put multiple entries in the HPT for a single 16MB page. This
capability is called mixed page-size segment (MPSS). With MPSS,
there are two relevant page sizes: the base page size, which is the
size used in searching the HPT, and the actual page size, which is the
size indicated in the HPT entry. [ Note that the actual page size is
always >= base page size ].
We use "ibm,segment-page-sizes" device tree node to advertise
the MPSS support to PAPR guest. The penc encoding indicates whether
we support a specific combination of base page size and actual
page size in the same segment. We also use the penc value in the
LP encoding of HPTE entry.
This patch exposes MPSS support to KVM guest by advertising the
feature via "ibm,segment-page-sizes". It also adds the necessary changes
to decode the base page size and the actual page size correctly from the
HPTE entry.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Today when KVM tries to reserve memory for the hash page table it
allocates from the normal page allocator first. If that fails it
falls back to CMA's reserved region. One of the side effects of
this is that we could end up exhausting the page allocator and
get linux into OOM conditions while we still have plenty of space
available in CMA.
This patch addresses this issue by first trying hash page table
allocation from CMA's reserved region before falling back to the normal
page allocator. So if we run out of memory, we really are out of memory.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 introduces transactional memory which brings along a number of new
registers and MSR bits.
Implementing all of those is a pretty big headache, so for now let's at least
emulate enough to make Linux's context switching code happy.
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 introduces a new facility called the "Event Based Branch" facility.
It contains of a few registers that indicate where a guest should branch to
when a defined event occurs and it's in PR mode.
We don't want to really enable EBB as it will create a big mess with !PR guest
mode while hardware is in PR and we don't really emulate the PMU anyway.
So instead, let's just leave it at emulation of all its registers.
Signed-off-by: Alexander Graf <agraf@suse.de>
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>
In parallel to the Processor ID Register (PIR) threaded POWER8 also adds a
Thread ID Register (TIR). Since PR KVM doesn't emulate more than one thread
per core, we can just always expose 0 here.
Signed-off-by: Alexander Graf <agraf@suse.de>
When we expose a POWER8 CPU into the guest, it will start accessing PMU SPRs
that we don't emulate. Just ignore accesses to them.
Signed-off-by: Alexander Graf <agraf@suse.de>
With the previous patches applied, we can now successfully use PR KVM on
little endian hosts which means we can now allow users to select it.
However, HV KVM still needs some work, so let's keep the kconfig conflict
on that one.
Signed-off-by: Alexander Graf <agraf@suse.de>
When the host CPU we're running on doesn't support dcbz32 itself, but the
guest wants to have dcbz only clear 32 bytes of data, we loop through every
executable mapped page to search for dcbz instructions and patch them with
a special privileged instruction that we emulate as dcbz32.
The only guests that want to see dcbz act as 32byte are book3s_32 guests, so
we don't have to worry about little endian instruction ordering. So let's
just always search for big endian dcbz instructions, also when we're on a
little endian host.
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>
We expose a blob of hypercall instructions to user space that it gives to
the guest via device tree again. That blob should contain a stream of
instructions necessary to do a hypercall in big endian, as it just gets
passed into the guest and old guests use them straight away.
Signed-off-by: Alexander Graf <agraf@suse.de>
When the guest does an RTAS hypercall it keeps all RTAS variables inside a
big endian data structure.
To make sure we don't have to bother about endianness inside the actual RTAS
handlers, let's just convert the whole structure to host endian before we
call our RTAS handlers and back to big endian when we return to the guest.
Signed-off-by: Alexander Graf <agraf@suse.de>
The HTAB on PPC is always in big endian. When we access it via hypercalls
on behalf of the guest and we're running on a little endian host, we need
to make sure we swap the bits accordingly.
Signed-off-by: Alexander Graf <agraf@suse.de>
The default MSR when user space does not define anything should be identical
on little and big endian hosts, so remove MSR_LE from it.
Signed-off-by: Alexander Graf <agraf@suse.de>
The "shadow SLB" in the PACA is shared with the hypervisor, so it has to
be big endian. We access the shadow SLB during world switch, so let's make
sure we access it in big endian even when we're on a little endian host.
Signed-off-by: Alexander Graf <agraf@suse.de>
The HTAB is always big endian. We access the guest's HTAB using
copy_from/to_user, but don't yet take care of the fact that we might
be running on an LE host.
Wrap all accesses to the guest HTAB with big endian accessors.
Signed-off-by: Alexander Graf <agraf@suse.de>
The HTAB is always big endian. We access the guest's HTAB using
copy_from/to_user, but don't yet take care of the fact that we might
be running on an LE host.
Wrap all accesses to the guest HTAB with big endian accessors.
Signed-off-by: Alexander Graf <agraf@suse.de>
Commit 9308ab8e2d made C/R HTAB updates go byte-wise into the target HTAB.
However, it didn't update the guest's copy of the HTAB, but instead the
host local copy of it.
Write to the guest's HTAB instead.
Signed-off-by: Alexander Graf <agraf@suse.de>
CC: Paul Mackerras <paulus@samba.org>
Acked-by: Paul Mackerras <paulus@samba.org>
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>
