Intel SDM says, that at most one LAPIC should be configured with ExtINT
delivery. KVM configures all LAPICs this way. This causes pic_unlock()
to kick the first available vCPU from the internal KVM data structures.
If this vCPU is not the BSP, but some not-yet-booted AP, the BSP may
never realize that there is an interrupt.
Fix that by enabling ExtINT delivery only for the BSP.
This allows booting a Linux guest without a TSC in the above situation.
Otherwise the BSP gets stuck in calibrate_delay_converge().
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Preemption can occur during cancel preemption timer, and there will be
inconsistent status in lapic, vmx and vmcs field.
CPU0 CPU1
preemption timer vmexit
handle_preemption_timer(vCPU0)
kvm_lapic_expired_hv_timer
vmx_cancel_hv_timer
vmx->hv_deadline_tsc = -1
vmcs_clear_bits
/* hv_timer_in_use still true */
sched_out
sched_in
kvm_arch_vcpu_load
vmx_set_hv_timer
write vmx->hv_deadline_tsc
vmcs_set_bits
/* back in kvm_lapic_expired_hv_timer */
hv_timer_in_use = false
...
vmx_vcpu_run
vmx_arm_hv_run
write preemption timer deadline
spurious preemption timer vmexit
handle_preemption_timer(vCPU0)
kvm_lapic_expired_hv_timer
WARN_ON(!apic->lapic_timer.hv_timer_in_use);
This can be reproduced sporadically during boot of L2 on a
preemptible L1, causing a splat on L1.
WARNING: CPU: 3 PID: 1952 at arch/x86/kvm/lapic.c:1529 kvm_lapic_expired_hv_timer+0xb5/0xd0 [kvm]
CPU: 3 PID: 1952 Comm: qemu-system-x86 Not tainted 4.12.0-rc1+ #24 RIP: 0010:kvm_lapic_expired_hv_timer+0xb5/0xd0 [kvm]
Call Trace:
handle_preemption_timer+0xe/0x20 [kvm_intel]
vmx_handle_exit+0xc9/0x15f0 [kvm_intel]
? lock_acquire+0xdb/0x250
? lock_acquire+0xdb/0x250
? kvm_arch_vcpu_ioctl_run+0xdf3/0x1ce0 [kvm]
kvm_arch_vcpu_ioctl_run+0xe55/0x1ce0 [kvm]
kvm_vcpu_ioctl+0x384/0x7b0 [kvm]
? kvm_vcpu_ioctl+0x384/0x7b0 [kvm]
? __fget+0xf3/0x210
do_vfs_ioctl+0xa4/0x700
? __fget+0x114/0x210
SyS_ioctl+0x79/0x90
do_syscall_64+0x8f/0x750
? trace_hardirqs_on_thunk+0x1a/0x1c
entry_SYSCALL64_slow_path+0x25/0x25
This patch fixes it by disabling preemption while cancelling
preemption timer. This way cancel_hv_timer is atomic with
respect to kvm_arch_vcpu_load.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Merge more updates from Andrew Morton:
- the rest of MM
- various misc things
- procfs updates
- lib/ updates
- checkpatch updates
- kdump/kexec updates
- add kvmalloc helpers, use them
- time helper updates for Y2038 issues. We're almost ready to remove
current_fs_time() but that awaits a btrfs merge.
- add tracepoints to DAX
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (114 commits)
drivers/staging/ccree/ssi_hash.c: fix build with gcc-4.4.4
selftests/vm: add a test for virtual address range mapping
dax: add tracepoint to dax_insert_mapping()
dax: add tracepoint to dax_writeback_one()
dax: add tracepoints to dax_writeback_mapping_range()
dax: add tracepoints to dax_load_hole()
dax: add tracepoints to dax_pfn_mkwrite()
dax: add tracepoints to dax_iomap_pte_fault()
mtd: nand: nandsim: convert to memalloc_noreclaim_*()
treewide: convert PF_MEMALLOC manipulations to new helpers
mm: introduce memalloc_noreclaim_{save,restore}
mm: prevent potential recursive reclaim due to clearing PF_MEMALLOC
mm/huge_memory.c: deposit a pgtable for DAX PMD faults when required
mm/huge_memory.c: use zap_deposited_table() more
time: delete CURRENT_TIME_SEC and CURRENT_TIME
gfs2: replace CURRENT_TIME with current_time
apparmorfs: replace CURRENT_TIME with current_time()
lustre: replace CURRENT_TIME macro
fs: ubifs: replace CURRENT_TIME_SEC with current_time
fs: ufs: use ktime_get_real_ts64() for birthtime
...
Patch series "kvmalloc", v5.
There are many open coded kmalloc with vmalloc fallback instances in the
tree. Most of them are not careful enough or simply do not care about
the underlying semantic of the kmalloc/page allocator which means that
a) some vmalloc fallbacks are basically unreachable because the kmalloc
part will keep retrying until it succeeds b) the page allocator can
invoke a really disruptive steps like the OOM killer to move forward
which doesn't sound appropriate when we consider that the vmalloc
fallback is available.
As it can be seen implementing kvmalloc requires quite an intimate
knowledge if the page allocator and the memory reclaim internals which
strongly suggests that a helper should be implemented in the memory
subsystem proper.
Most callers, I could find, have been converted to use the helper
instead. This is patch 6. There are some more relying on __GFP_REPEAT
in the networking stack which I have converted as well and Eric Dumazet
was not opposed [2] to convert them as well.
[1] http://lkml.kernel.org/r/20170130094940.13546-1-mhocko@kernel.org
[2] http://lkml.kernel.org/r/1485273626.16328.301.camel@edumazet-glaptop3.roam.corp.google.com
This patch (of 9):
Using kmalloc with the vmalloc fallback for larger allocations is a
common pattern in the kernel code. Yet we do not have any common helper
for that and so users have invented their own helpers. Some of them are
really creative when doing so. Let's just add kv[mz]alloc and make sure
it is implemented properly. This implementation makes sure to not make
a large memory pressure for > PAGE_SZE requests (__GFP_NORETRY) and also
to not warn about allocation failures. This also rules out the OOM
killer as the vmalloc is a more approapriate fallback than a disruptive
user visible action.
This patch also changes some existing users and removes helpers which
are specific for them. In some cases this is not possible (e.g.
ext4_kvmalloc, libcfs_kvzalloc) because those seems to be broken and
require GFP_NO{FS,IO} context which is not vmalloc compatible in general
(note that the page table allocation is GFP_KERNEL). Those need to be
fixed separately.
While we are at it, document that __vmalloc{_node} about unsupported gfp
mask because there seems to be a lot of confusion out there.
kvmalloc_node will warn about GFP_KERNEL incompatible (which are not
superset) flags to catch new abusers. Existing ones would have to die
slowly.
[sfr@canb.auug.org.au: f2fs fixup]
Link: http://lkml.kernel.org/r/20170320163735.332e64b7@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170306103032.2540-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Andreas Dilger <adilger@dilger.ca> [ext4 part]
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit bbd6411513.
I've been sitting on this revert for too long and it unfortunately
missed 4.11. It's also the reason why I haven't merged ring-based
dirty tracking for 4.12.
Using kvm_vcpu_memslots in kvm_gfn_to_hva_cache_init and
kvm_vcpu_write_guest_offset_cached means that the MSR value can
now be used to access SMRAM, simply by making it point to an SMRAM
physical address. This is problematic because it lets the guest
OS overwrite memory that it shouldn't be able to touch.
Cc: stable@vger.kernel.org
Fixes: bbd6411513
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Provide versions of struct gfn_to_hva_cache functions that
take vcpu as a parameter instead of struct kvm. The existing functions
are not needed anymore, so delete them. This allows dirty pages to
be logged in the vcpu dirty ring, instead of the global dirty ring,
for ring-based dirty memory tracking.
Signed-off-by: Lei Cao <lei.cao@stratus.com>
Message-Id: <CY1PR08MB19929BD2AC47A291FD680E83F04F0@CY1PR08MB1992.namprd08.prod.outlook.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since bf9f6ac8d7 ("KVM: Update Posted-Interrupts Descriptor when vCPU
is blocked", 2015-09-18) the posted interrupt descriptor is checked
unconditionally for PIR.ON. Therefore we don't need KVM_REQ_EVENT to
trigger the scan and, if NMIs or SMIs are not involved, we can avoid
the complicated event injection path.
Calling kvm_vcpu_kick if PIR.ON=1 is also useless, though it has been
there since APICv was introduced.
However, without the KVM_REQ_EVENT safety net KVM needs to be much
more careful about races between vmx_deliver_posted_interrupt and
vcpu_enter_guest. First, the IPI for posted interrupts may be issued
between setting vcpu->mode = IN_GUEST_MODE and disabling interrupts.
If that happens, kvm_trigger_posted_interrupt returns true, but
smp_kvm_posted_intr_ipi doesn't do anything about it. The guest is
entered with PIR.ON, but the posted interrupt IPI has not been sent
and the interrupt is only delivered to the guest on the next vmentry
(if any). To fix this, disable interrupts before setting vcpu->mode.
This ensures that the IPI is delayed until the guest enters non-root mode;
it is then trapped by the processor causing the interrupt to be injected.
Second, the IPI may be issued between kvm_x86_ops->sync_pir_to_irr(vcpu)
and vcpu->mode = IN_GUEST_MODE. In this case, kvm_vcpu_kick is called
but it (correctly) doesn't do anything because it sees vcpu->mode ==
OUTSIDE_GUEST_MODE. Again, the guest is entered with PIR.ON but no
posted interrupt IPI is pending; this time, the fix for this is to move
the RVI update after IN_GUEST_MODE.
Both issues were mostly masked by the liberal usage of KVM_REQ_EVENT,
though the second could actually happen with VT-d posted interrupts.
In both race scenarios KVM_REQ_EVENT would cancel guest entry, resulting
in another vmentry which would inject the interrupt.
This saves about 300 cycles on the self_ipi_* tests of vmexit.flat.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Calls to apic_find_highest_irr are scanning IRR twice, once
in vmx_sync_pir_from_irr and once in apic_search_irr. Change
sync_pir_from_irr to get the new maximum IRR from kvm_apic_update_irr;
now that it does the computation, it can also do the RVI write.
In order to avoid complications in svm.c, make the callback optional.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pending interrupts might be in the PI descriptor when the
LAPIC is restored from an external state; we do not want
them to be injected.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM's lapic emulation uses static_key_deferred (apic_{hw,sw}_disabled).
These are implemented with delayed_work structs which can still be
pending when the KVM module is unloaded. We've seen this cause kernel
panics when the kvm_intel module is quickly reloaded.
Use the new static_key_deferred_flush() API to flush pending updates on
module unload.
Signed-off-by: David Matlack <dmatlack@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On interrupt delivery the PPR can only grow (except for auto-EOI),
so it is impossible that non-auto-EOI interrupt delivery results
in KVM_REQ_EVENT. We can therefore use __apic_update_ppr.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On PPR update, we set KVM_REQ_EVENT unconditionally anytime PPR is lowered.
But we can take into account IRR here already.
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
PPR needs to be updated whenever on every IRR read because we
may have missed TPR writes that _increased_ PPR. However, these
writes need not generate KVM_REQ_EVENT, because either KVM_REQ_EVENT
has been set already in __apic_accept_irq, or we are going to
process the interrupt right away.
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since we're already in VCPU context, all we have to do here is recompute
the PPR value. That will in turn generate a KVM_REQ_EVENT if necessary.
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
LAPIC after reset is in xAPIC mode, which poses a problem for hotplug of
VCPUs with high APIC ID, because reset VCPU is waiting for INIT/SIPI,
but there is no way to uniquely address it using xAPIC.
From many possible options, we chose the one that also works on real
hardware: accepting interrupts addressed to LAPIC's x2APIC ID even in
xAPIC mode.
KVM intentionally differs from real hardware, because real hardware
(Knights Landing) does just "x2apic_id & 0xff" to decide whether to
accept the interrupt in xAPIC mode and it can deliver one interrupt to
more than one physical destination, e.g. 0x123 to 0x123 and 0x23.
Fixes: 682f732ecf ("KVM: x86: bump MAX_VCPUS to 288")
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Slow path tried to prevent IPIs from x2APIC VCPUs from being delivered
to xAPIC VCPUs and vice-versa. Make slow path behave like fast path,
which never distinguished that.
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There were three calls sites:
- recalculate_apic_map and kvm_apic_match_physical_addr, where it would
only complicate implementation of x2APIC hotplug;
- in apic_debug, where it was still somewhat preserved, but keeping the
old function just for apic_debug was not worth it
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
x86: userspace can now hide nested VMX features from guests; nested
VMX can now run Hyper-V in a guest; support for AVX512_4VNNIW and
AVX512_FMAPS in KVM; infrastructure support for virtual Intel GPUs.
PPC: support for KVM guests on POWER9; improved support for interrupt
polling; optimizations and cleanups.
s390: two small optimizations, more stuff is in flight and will be
in 4.11.
ARM: support for the GICv3 ITS on 32bit platforms.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"Small release, the most interesting stuff is x86 nested virt
improvements.
x86:
- userspace can now hide nested VMX features from guests
- nested VMX can now run Hyper-V in a guest
- support for AVX512_4VNNIW and AVX512_FMAPS in KVM
- infrastructure support for virtual Intel GPUs.
PPC:
- support for KVM guests on POWER9
- improved support for interrupt polling
- optimizations and cleanups.
s390:
- two small optimizations, more stuff is in flight and will be in
4.11.
ARM:
- support for the GICv3 ITS on 32bit platforms"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (94 commits)
arm64: KVM: pmu: Reset PMSELR_EL0.SEL to a sane value before entering the guest
KVM: arm/arm64: timer: Check for properly initialized timer on init
KVM: arm/arm64: vgic-v2: Limit ITARGETSR bits to number of VCPUs
KVM: x86: Handle the kthread worker using the new API
KVM: nVMX: invvpid handling improvements
KVM: nVMX: check host CR3 on vmentry and vmexit
KVM: nVMX: introduce nested_vmx_load_cr3 and call it on vmentry
KVM: nVMX: propagate errors from prepare_vmcs02
KVM: nVMX: fix CR3 load if L2 uses PAE paging and EPT
KVM: nVMX: load GUEST_EFER after GUEST_CR0 during emulated VM-entry
KVM: nVMX: generate MSR_IA32_CR{0,4}_FIXED1 from guest CPUID
KVM: nVMX: fix checks on CR{0,4} during virtual VMX operation
KVM: nVMX: support restore of VMX capability MSRs
KVM: nVMX: generate non-true VMX MSRs based on true versions
KVM: x86: Do not clear RFLAGS.TF when a singlestep trap occurs.
KVM: x86: Add kvm_skip_emulated_instruction and use it.
KVM: VMX: Move skip_emulated_instruction out of nested_vmx_check_vmcs12
KVM: VMX: Reorder some skip_emulated_instruction calls
KVM: x86: Add a return value to kvm_emulate_cpuid
KVM: PPC: Book3S: Move prototypes for KVM functions into kvm_ppc.h
...
From the Intel SDM, volume 3, section 10.4.3, "Enabling or Disabling the
Local APIC,"
When IA32_APIC_BASE[11] is 0, the processor is functionally equivalent
to an IA-32 processor without an on-chip APIC. The CPUID feature flag
for the APIC (see Section 10.4.2, "Presence of the Local APIC") is
also set to 0.
Signed-off-by: Jim Mattson <jmattson@google.com>
[Changed subject tag from nVMX to x86.]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
On some benchmarks (e.g. netperf with ioeventfd disabled), APICv
posted interrupts turn out to be slower than interrupt injection via
KVM_REQ_EVENT.
This patch optimizes a bit the IRR update, avoiding expensive atomic
operations in the common case where PI.ON=0 at vmentry or the PIR vector
is mostly zero. This saves at least 20 cycles (1%) per vmexit, as
measured by kvm-unit-tests' inl_from_qemu test (20 runs):
| enable_apicv=1 | enable_apicv=0
| mean stdev | mean stdev
----------|-----------------|------------------
before | 5826 32.65 | 5765 47.09
after | 5809 43.42 | 5777 77.02
Of course, any change in the right column is just placebo effect. :)
The savings are bigger if interrupts are frequent.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Most windows guests still utilize APIC Timer periodic/oneshot mode
instead of tsc-deadline mode, and the APIC Timer periodic/oneshot
mode are still emulated by high overhead hrtimer on host. This patch
converts the expected expire time of the periodic/oneshot mode to
guest deadline tsc in order to leverage VMX preemption timer logic
for APIC Timer tsc-deadline mode. After each preemption timer vmexit
preemption timer is restarted to emulate LVTT current-count register
is automatically reloaded from the initial-count register when the
count reaches 0. This patch reduces ~5600 cycles for each APIC Timer
periodic mode operation virtualization.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[Squashed with my fixes that were reviewed-by Paolo.]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Rename start/cancel_hv_tscdeadline to start/cancel_hv_timer since
they will handle both APIC Timer periodic/oneshot mode and tsc-deadline
mode.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Check apic_lvtt_tscdeadline() mode directly instead of apic_lvtt_oneshot()
and apic_lvtt_period() to guarantee the timer is in tsc-deadline mode when
rdmsr MSR_IA32_TSCDEADLINE.
Suggested-by: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Extract start_sw_period() to handle periodic/oneshot mode, it will be
used by later patch.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
APIC map table is recalculated during reset APIC ID to the initial value
when enabling LAPIC. This patch move the recalculate_apic_map() to the
next branch since we don't need to recalculate apic map twice in current
codes.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
VGIC implementation.
- s390: support for trapping software breakpoints, nested virtualization
(vSIE), the STHYI opcode, initial extensions for CPU model support.
- MIPS: support for MIPS64 hosts (32-bit guests only) and lots of cleanups,
preliminary to this and the upcoming support for hardware virtualization
extensions.
- x86: support for execute-only mappings in nested EPT; reduced vmexit
latency for TSC deadline timer (by about 30%) on Intel hosts; support for
more than 255 vCPUs.
- PPC: bugfixes.
The ugly bit is the conflicts. A couple of them are simple conflicts due
to 4.7 fixes, but most of them are with other trees. There was definitely
too much reliance on Acked-by here. Some conflicts are for KVM patches
where _I_ gave my Acked-by, but the worst are for this pull request's
patches that touch files outside arch/*/kvm. KVM submaintainers should
probably learn to synchronize better with arch maintainers, with the
latter providing topic branches whenever possible instead of Acked-by.
This is what we do with arch/x86. And I should learn to refuse pull
requests when linux-next sends scary signals, even if that means that
submaintainers have to rebase their branches.
Anyhow, here's the list:
- arch/x86/kvm/vmx.c: handle_pcommit and EXIT_REASON_PCOMMIT was removed
by the nvdimm tree. This tree adds handle_preemption_timer and
EXIT_REASON_PREEMPTION_TIMER at the same place. In general all mentions
of pcommit have to go.
There is also a conflict between a stable fix and this patch, where the
stable fix removed the vmx_create_pml_buffer function and its call.
- virt/kvm/kvm_main.c: kvm_cpu_notifier was removed by the hotplug tree.
This tree adds kvm_io_bus_get_dev at the same place.
- virt/kvm/arm/vgic.c: a few final bugfixes went into 4.7 before the
file was completely removed for 4.8.
- include/linux/irqchip/arm-gic-v3.h: this one is entirely our fault;
this is a change that should have gone in through the irqchip tree and
pulled by kvm-arm. I think I would have rejected this kvm-arm pull
request. The KVM version is the right one, except that it lacks
GITS_BASER_PAGES_SHIFT.
- arch/powerpc: what a mess. For the idle_book3s.S conflict, the KVM
tree is the right one; everything else is trivial. In this case I am
not quite sure what went wrong. The commit that is causing the mess
(fd7bacbca4, "KVM: PPC: Book3S HV: Fix TB corruption in guest exit
path on HMI interrupt", 2016-05-15) touches both arch/powerpc/kernel/
and arch/powerpc/kvm/. It's large, but at 396 insertions/5 deletions
I guessed that it wasn't really possible to split it and that the 5
deletions wouldn't conflict. That wasn't the case.
- arch/s390: also messy. First is hypfs_diag.c where the KVM tree
moved some code and the s390 tree patched it. You have to reapply the
relevant part of commits 6c22c98637, plus all of e030c1125e, to
arch/s390/kernel/diag.c. Or pick the linux-next conflict
resolution from http://marc.info/?l=kvm&m=146717549531603&w=2.
Second, there is a conflict in gmap.c between a stable fix and 4.8.
The KVM version here is the correct one.
I have pushed my resolution at refs/heads/merge-20160802 (commit
3d1f53419842) at git://git.kernel.org/pub/scm/virt/kvm/kvm.git.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
- ARM: GICv3 ITS emulation and various fixes. Removal of the
old VGIC implementation.
- s390: support for trapping software breakpoints, nested
virtualization (vSIE), the STHYI opcode, initial extensions
for CPU model support.
- MIPS: support for MIPS64 hosts (32-bit guests only) and lots
of cleanups, preliminary to this and the upcoming support for
hardware virtualization extensions.
- x86: support for execute-only mappings in nested EPT; reduced
vmexit latency for TSC deadline timer (by about 30%) on Intel
hosts; support for more than 255 vCPUs.
- PPC: bugfixes.
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (302 commits)
KVM: PPC: Introduce KVM_CAP_PPC_HTM
MIPS: Select HAVE_KVM for MIPS64_R{2,6}
MIPS: KVM: Reset CP0_PageMask during host TLB flush
MIPS: KVM: Fix ptr->int cast via KVM_GUEST_KSEGX()
MIPS: KVM: Sign extend MFC0/RDHWR results
MIPS: KVM: Fix 64-bit big endian dynamic translation
MIPS: KVM: Fail if ebase doesn't fit in CP0_EBase
MIPS: KVM: Use 64-bit CP0_EBase when appropriate
MIPS: KVM: Set CP0_Status.KX on MIPS64
MIPS: KVM: Make entry code MIPS64 friendly
MIPS: KVM: Use kmap instead of CKSEG0ADDR()
MIPS: KVM: Use virt_to_phys() to get commpage PFN
MIPS: Fix definition of KSEGX() for 64-bit
KVM: VMX: Add VMCS to CPU's loaded VMCSs before VMPTRLD
kvm: x86: nVMX: maintain internal copy of current VMCS
KVM: PPC: Book3S HV: Save/restore TM state in H_CEDE
KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures
KVM: arm64: vgic-its: Simplify MAPI error handling
KVM: arm64: vgic-its: Make vgic_its_cmd_handle_mapi similar to other handlers
KVM: arm64: vgic-its: Turn device_id validation into generic ID validation
...
Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends. That changed
when we forked out support for the latter into the export.h file.
This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig. In the case of
kvm where it is modular, we can extend that to also include files
that are building basic support functionality but not related
to loading or registering the final module; such files also have
no need whatsoever for module.h
The advantage in removing such instances is that module.h itself
sources about 15 other headers; adding significantly to what we feed
cpp, and it can obscure what headers we are effectively using.
Since module.h was the source for init.h (for __init) and for
export.h (for EXPORT_SYMBOL) we consider each instance for the
presence of either and replace as needed.
Several instances got replaced with moduleparam.h since that was
really all that was required for those particular files.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/20160714001901.31603-8-paul.gortmaker@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kzalloc was replaced with kvm_kvzalloc to allow non-contiguous areas and
rcu had to be modified to cope with it.
The practical limit for KVM_MAX_VCPU_ID right now is INT_MAX, but lower
value was chosen in case there were bugs. 1023 is sufficient maximum
APIC ID for 288 VCPUs.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK as a feature flag to
KVM_CAP_X2APIC_API.
The quirk made KVM interpret 0xff as a broadcast even in x2APIC mode.
The enableable capability is needed in order to support standard x2APIC and
remain backward compatible.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
[Expand kvm_apic_mda comment. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM_CAP_X2APIC_API is a capability for features related to x2APIC
enablement. KVM_X2APIC_API_32BIT_FORMAT feature can be enabled to
extend APIC ID in get/set ioctl and MSI addresses to 32 bits.
Both are needed to support x2APIC.
The feature has to be enableable and disabled by default, because
get/set ioctl shifted and truncated APIC ID to 8 bits by using a
non-standard protocol inspired by xAPIC and the change is not
backward-compatible.
Changes to MSI addresses follow the format used by interrupt remapping
unit. The upper address word, that used to be 0, contains upper 24 bits
of the LAPIC address in its upper 24 bits. Lower 8 bits are reserved as
0. Using the upper address word is not backward-compatible either as we
didn't check that userspace zeroed the word. Reserved bits are still
not explicitly checked, but non-zero data will affect LAPIC addresses,
which will cause a bug.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
LAPIC is reset in xAPIC mode and the surrounding code expects that.
KVM never resets after initialization. This patch is just for sanity.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
APIC ID should be set to the initial APIC ID when enabling LAPIC.
This only matters if the guest changes APIC ID. No sane OS does that.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We currently always shift APIC ID as if APIC was in xAPIC mode.
x2APIC mode wants to use more bits and storing a hardware-compabible
value is the the sanest option.
KVM API to set the lapic expects that bottom 8 bits of APIC ID are in
top 8 bits of APIC_ID register, so the register needs to be shifted in
x2APIC mode.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x2APIC supports up to 2^32-1 LAPICs, but most guest in coming years will
probably has fewer VCPUs. Dynamic size saves memory at the cost of
turning one constant into a variable.
apic_map mutex had to be moved before allocation to avoid races with cpu
hotplug.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Logical x2APIC IDs map injectively to physical x2APIC IDs, so we can
reuse the physical array for them. This allows us to save space by
sizing the logical maps according to the needs of xAPIC.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_irq_delivery_to_apic_fast and kvm_intr_is_single_vcpu_fast both
compute the interrupt destination. Factor the code.
'struct kvm_lapic **dst = NULL' had to be added to silence GCC.
GCC might complain about potential NULL access in the future, because it
missed conditions that avoided uninitialized uses of dst.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
INFO: rcu_sched detected stalls on CPUs/tasks:
1-...: (11800 GPs behind) idle=45d/140000000000000/0 softirq=0/0 fqs=21663
(detected by 0, t=65016 jiffies, g=11500, c=11499, q=719)
Task dump for CPU 1:
qemu-system-x86 R running task 0 3529 3525 0x00080808
ffff8802021791a0 ffff880212895040 0000000000000001 00007f1c2c00db40
ffff8801dd20fcd3 ffffc90002b98000 ffff8801dd20fc88 ffff8801dd20fcf8
0000000000000286 ffff8801dd2ac538 ffff8801dd20fcc0 ffffffffc06949c9
Call Trace:
? kvm_write_guest_cached+0xb9/0x160 [kvm]
? __delay+0xf/0x20
? wait_lapic_expire+0x14a/0x200 [kvm]
? kvm_arch_vcpu_ioctl_run+0xcbe/0x1b00 [kvm]
? kvm_arch_vcpu_ioctl_run+0xe34/0x1b00 [kvm]
? kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
? __fget+0x5/0x210
? do_vfs_ioctl+0x96/0x6a0
? __fget_light+0x2a/0x90
? SyS_ioctl+0x79/0x90
? do_syscall_64+0x7c/0x1e0
? entry_SYSCALL64_slow_path+0x25/0x25
This can be reproduced readily by running a full dynticks guest(since hrtimer
in guest is heavily used) w/ lapic_timer_advance disabled.
If fail to program hardware preemption timer, we will fallback to hrtimer based
method, however, a previous programmed preemption timer miss to cancel in this
scenario which results in one hardware preemption timer and one hrtimer emulated
tsc deadline timer run simultaneously. So sometimes the target guest deadline
tsc is earlier than guest tsc, which leads to the computation in vmx_set_hv_timer
can underflow and cause delta_tsc to be set a huge value, then host soft lockup
as above.
This patch fix it by cancelling the previous programmed preemption timer if there
is once we failed to program the new preemption timer and fallback to hrtimer
based method.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The host timer which emulates the guest LAPIC TSC deadline
timer has its expiration diminished by lapic_timer_advance_ns
nanoseconds. Therefore if, at wait_lapic_expire, a difference
larger than lapic_timer_advance_ns is encountered, delay at most
lapic_timer_advance_ns.
This fixes a problem where the guest can cause the host
to delay for large amounts of time.
Reported-by: Alan Jenkins <alan.christopher.jenkins@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The VMX preemption timer can be used to virtualize the TSC deadline timer.
The VMX preemption timer is armed when the vCPU is running, and a VMExit
will happen if the virtual TSC deadline timer expires.
When the vCPU thread is blocked because of HLT, KVM will switch to use
an hrtimer, and then go back to the VMX preemption timer when the vCPU
thread is unblocked.
This solution avoids the complex OS's hrtimer system, and the host
timer interrupt handling cost, replacing them with a little math
(for guest->host TSC and host TSC->preemption timer conversion)
and a cheaper VMexit. This benefits latency for isolated pCPUs.
[A word about performance... Yunhong reported a 30% reduction in average
latency from cyclictest. I made a similar test with tscdeadline_latency
from kvm-unit-tests, and measured
- ~20 clock cycles loss (out of ~3200, so less than 1% but still
statistically significant) in the worst case where the test halts
just after programming the TSC deadline timer
- ~800 clock cycles gain (25% reduction in latency) in the best case
where the test busy waits.
I removed the VMX bits from Yunhong's patch, to concentrate them in the
next patch - Paolo]
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The function to start the tsc deadline timer virtualization will be used
also by the pre_block hook when we use the preemption timer; change it
to a separate function. No logic changes.
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Neither APICv nor AVIC actually need the first argument of
hwapic_isr_update, but the vCPU makes more sense than passing the
pointer to the whole virtual machine! In fact in the APICv case it's
just happening that the vCPU is used implicitly, through the loaded VMCS.
The second argument instead is named differently, make it consistent.
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan H. Schönherr