Pull core timer updates from Thomas Gleixner:
"Timers and timekeeping updates:
- A large overhaul of the posix CPU timer code which is a preparation
for moving the CPU timer expiry out into task work so it can be
properly accounted on the task/process.
An update to the bogus permission checks will come later during the
merge window as feedback was not complete before heading of for
travel.
- Switch the timerqueue code to use cached rbtrees and get rid of the
homebrewn caching of the leftmost node.
- Consolidate hrtimer_init() + hrtimer_init_sleeper() calls into a
single function
- Implement the separation of hrtimers to be forced to expire in hard
interrupt context even when PREEMPT_RT is enabled and mark the
affected timers accordingly.
- Implement a mechanism for hrtimers and the timer wheel to protect
RT against priority inversion and live lock issues when a (hr)timer
which should be canceled is currently executing the callback.
Instead of infinitely spinning, the task which tries to cancel the
timer blocks on a per cpu base expiry lock which is held and
released by the (hr)timer expiry code.
- Enable the Hyper-V TSC page based sched_clock for Hyper-V guests
resulting in faster access to timekeeping functions.
- Updates to various clocksource/clockevent drivers and their device
tree bindings.
- The usual small improvements all over the place"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
posix-cpu-timers: Fix permission check regression
posix-cpu-timers: Always clear head pointer on dequeue
hrtimer: Add a missing bracket and hide `migration_base' on !SMP
posix-cpu-timers: Make expiry_active check actually work correctly
posix-timers: Unbreak CONFIG_POSIX_TIMERS=n build
tick: Mark sched_timer to expire in hard interrupt context
hrtimer: Add kernel doc annotation for HRTIMER_MODE_HARD
x86/hyperv: Hide pv_ops access for CONFIG_PARAVIRT=n
posix-cpu-timers: Utilize timerqueue for storage
posix-cpu-timers: Move state tracking to struct posix_cputimers
posix-cpu-timers: Deduplicate rlimit handling
posix-cpu-timers: Remove pointless comparisons
posix-cpu-timers: Get rid of 64bit divisions
posix-cpu-timers: Consolidate timer expiry further
posix-cpu-timers: Get rid of zero checks
rlimit: Rewrite non-sensical RLIMIT_CPU comment
posix-cpu-timers: Respect INFINITY for hard RTTIME limit
posix-cpu-timers: Switch thread group sampling to array
posix-cpu-timers: Restructure expiry array
posix-cpu-timers: Remove cputime_expires
...
James Harvey reported a livelock that was introduced by commit
d012a06ab1 ("Revert "KVM: x86/mmu: Zap only the relevant pages when
removing a memslot"").
The livelock occurs because kvm_mmu_zap_all() as it exists today will
voluntarily reschedule and drop KVM's mmu_lock, which allows other vCPUs
to add shadow pages. With enough vCPUs, kvm_mmu_zap_all() can get stuck
in an infinite loop as it can never zap all pages before observing lock
contention or the need to reschedule. The equivalent of kvm_mmu_zap_all()
that was in use at the time of the reverted commit (4e103134b8, "KVM:
x86/mmu: Zap only the relevant pages when removing a memslot") employed
a fast invalidate mechanism and was not susceptible to the above livelock.
There are three ways to fix the livelock:
- Reverting the revert (commit d012a06ab1) is not a viable option as
the revert is needed to fix a regression that occurs when the guest has
one or more assigned devices. It's unlikely we'll root cause the device
assignment regression soon enough to fix the regression timely.
- Remove the conditional reschedule from kvm_mmu_zap_all(). However, although
removing the reschedule would be a smaller code change, it's less safe
in the sense that the resulting kvm_mmu_zap_all() hasn't been used in
the wild for flushing memslots since the fast invalidate mechanism was
introduced by commit 6ca18b6950 ("KVM: x86: use the fast way to
invalidate all pages"), back in 2013.
- Reintroduce the fast invalidate mechanism and use it when zapping shadow
pages in response to a memslot being deleted/moved, which is what this
patch does.
For all intents and purposes, this is a revert of commit ea145aacf4
("Revert "KVM: MMU: fast invalidate all pages"") and a partial revert of
commit 7390de1e99 ("Revert "KVM: x86: use the fast way to invalidate
all pages""), i.e. restores the behavior of commit 5304b8d37c ("KVM:
MMU: fast invalidate all pages") and commit 6ca18b6950 ("KVM: x86:
use the fast way to invalidate all pages") respectively.
Fixes: d012a06ab1 ("Revert "KVM: x86/mmu: Zap only the relevant pages when removing a memslot"")
Reported-by: James Harvey <jamespharvey20@gmail.com>
Cc: Alex Willamson <alex.williamson@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Emulation of VMPTRST can incorrectly inject a page fault
when passed an operand that points to an MMIO address.
The page fault will use uninitialized kernel stack memory
as the CR2 and error code.
The right behavior would be to abort the VM with a KVM_EXIT_INTERNAL_ERROR
exit to userspace; however, it is not an easy fix, so for now just ensure
that the error code and CR2 are zero.
Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Cc: stable@vger.kernel.org
[add comment]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The implementation of vmread to memory is still incomplete, as it
lacks the ability to do vmread to I/O memory just like vmptrst.
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Don't advance RIP or inject a single-step #DB if emulation signals a
fault. This logic applies to all state updates that are conditional on
clean retirement of the emulation instruction, e.g. updating RFLAGS was
previously handled by commit 38827dbd3f ("KVM: x86: Do not update
EFLAGS on faulting emulation").
Not advancing RIP is likely a nop, i.e. ctxt->eip isn't updated with
ctxt->_eip until emulation "retires" anyways. Skipping #DB injection
fixes a bug reported by Andy Lutomirski where a #UD on SYSCALL due to
invalid state with EFLAGS.TF=1 would loop indefinitely due to emulation
overwriting the #UD with #DB and thus restarting the bad SYSCALL over
and over.
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: stable@vger.kernel.org
Reported-by: Andy Lutomirski <luto@kernel.org>
Fixes: 663f4c61b8 ("KVM: x86: handle singlestep during emulation")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
If kvm_intel is loaded with nested=0 parameter an attempt to perform
KVM_GET_SUPPORTED_HV_CPUID results in OOPS as nested_get_evmcs_version hook
in kvm_x86_ops is NULL (we assign it in nested_vmx_hardware_setup() and
this only happens in case nested is enabled).
Check that kvm_x86_ops->nested_get_evmcs_version is not NULL before
calling it. With this, we can remove the stub from svm as it is no
longer needed.
Cc: <stable@vger.kernel.org>
Fixes: e2e871ab2f ("x86/kvm/hyper-v: Introduce nested_get_evmcs_version() helper")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
This reverts commit 4e103134b8.
Alex Williamson reported regressions with device assignment with
this patch. Even though the bug is probably elsewhere and still
latent, this is needed to fix the regression.
Fixes: 4e103134b8 ("KVM: x86/mmu: Zap only the relevant pages when removing a memslot", 2019-02-05)
Reported-by: Alex Willamson <alex.williamson@redhat.com>
Cc: stable@vger.kernel.org
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
new_entry is reassigned a new value next line. So
it's redundant and remove it.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
recalculate_apic_map does not santize ldr and it's possible that
multiple bits are set. In that case, a previous valid entry
can potentially be overwritten by an invalid one.
This condition is hit when booting a 32 bit, >8 CPU, RHEL6 guest and then
triggering a crash to boot a kdump kernel. This is the sequence of
events:
1. Linux boots in bigsmp mode and enables PhysFlat, however, it still
writes to the LDR which probably will never be used.
2. However, when booting into kdump, the stale LDR values remain as
they are not cleared by the guest and there isn't a apic reset.
3. kdump boots with 1 cpu, and uses Logical Destination Mode but the
logical map has been overwritten and points to an inactive vcpu.
Signed-off-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.
Also, when doing this, change kvm_arch_create_vcpu_debugfs() to return
void instead of an integer, as we should not care at all about if this
function actually does anything or not.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <x86@kernel.org>
Cc: <kvm@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There is no need for this function as all arches have to implement
kvm_arch_create_vcpu_debugfs() no matter what. A #define symbol
let us actually simplify the code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After commit d73eb57b80 (KVM: Boost vCPUs that are delivering interrupts), a
five years old bug is exposed. Running ebizzy benchmark in three 80 vCPUs VMs
on one 80 pCPUs Skylake server, a lot of rcu_sched stall warning splatting
in the VMs after stress testing:
INFO: rcu_sched detected stalls on CPUs/tasks: { 4 41 57 62 77} (detected by 15, t=60004 jiffies, g=899, c=898, q=15073)
Call Trace:
flush_tlb_mm_range+0x68/0x140
tlb_flush_mmu.part.75+0x37/0xe0
tlb_finish_mmu+0x55/0x60
zap_page_range+0x142/0x190
SyS_madvise+0x3cd/0x9c0
system_call_fastpath+0x1c/0x21
swait_active() sustains to be true before finish_swait() is called in
kvm_vcpu_block(), voluntarily preempted vCPUs are taken into account
by kvm_vcpu_on_spin() loop greatly increases the probability condition
kvm_arch_vcpu_runnable(vcpu) is checked and can be true, when APICv
is enabled the yield-candidate vCPU's VMCS RVI field leaks(by
vmx_sync_pir_to_irr()) into spinning-on-a-taken-lock vCPU's current
VMCS.
This patch fixes it by checking conservatively a subset of events.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: stable@vger.kernel.org
Fixes: 98f4a1467 (KVM: add kvm_arch_vcpu_runnable() test to kvm_vcpu_on_spin() loop)
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_set_pending_timer() will take care to wake up the sleeping vCPU which
has pending timer, don't need to check this in apic_timer_expired() again.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On PREEMPT_RT enabled kernels unmarked hrtimers are moved into soft
interrupt expiry mode by default.
While that's not a functional requirement for the KVM local APIC timer
emulation, it's a latency issue which can be avoided by marking the timer
so hard interrupt context expiry is enforced.
No functional change.
[ tglx: Split out from larger combo patch. Add changelog. ]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190726185753.363363474@linutronix.de
Commit 11752adb (locking/pvqspinlock: Implement hybrid PV queued/unfair locks)
introduces hybrid PV queued/unfair locks
- queued mode (no starvation)
- unfair mode (good performance on not heavily contended lock)
The lock waiter goes into the unfair mode especially in VMs with over-commit
vCPUs since increaing over-commitment increase the likehood that the queue
head vCPU may have been preempted and not actively spinning.
However, reschedule queue head vCPU timely to acquire the lock still can get
better performance than just depending on lock stealing in over-subscribe
scenario.
Testing on 80 HT 2 socket Xeon Skylake server, with 80 vCPUs VM 80GB RAM:
ebizzy -M
vanilla boosting improved
1VM 23520 25040 6%
2VM 8000 13600 70%
3VM 3100 5400 74%
The lock holder vCPU yields to the queue head vCPU when unlock, to boost queue
head vCPU which is involuntary preemption or the one which is voluntary halt
due to fail to acquire the lock after a short spin in the guest.
Cc: Waiman Long <longman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Renaming docs seems to be en vogue at the moment, so fix on of the
grossly misnamed directories. We usually never use "virtual" as
a shortcut for virtualization in the kernel, but always virt,
as seen in the virt/ top-level directory. Fix up the documentation
to match that.
Fixes: ed16648eb5 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After reverting commit 240c35a378 (kvm: x86: Use task structs fpu field
for user), struct kvm_vcpu is 19456 bytes on my server, PAGE_ALLOC_COSTLY_ORDER(3)
is the order at which allocations are deemed costly to service. In serveless
scenario, one host can service hundreds/thoudands firecracker/kata-container
instances, howerver, new instance will fail to launch after memory is too
fragmented to allocate kvm_vcpu struct on host, this was observed in some
cloud provider product environments.
This patch dynamically allocates user_fpu, kvm_vcpu is 15168 bytes now on my
Skylake server.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The idea before commit 240c35a37 (which has just been reverted)
was that we have the following FPU states:
userspace (QEMU) guest
---------------------------------------------------------------------------
processor vcpu->arch.guest_fpu
>>> KVM_RUN: kvm_load_guest_fpu
vcpu->arch.user_fpu processor
>>> preempt out
vcpu->arch.user_fpu current->thread.fpu
>>> preempt in
vcpu->arch.user_fpu processor
>>> back to userspace
>>> kvm_put_guest_fpu
processor vcpu->arch.guest_fpu
---------------------------------------------------------------------------
With the new lazy model we want to get the state back to the processor
when schedule in from current->thread.fpu.
Reported-by: Thomas Lambertz <mail@thomaslambertz.de>
Reported-by: anthony <antdev66@gmail.com>
Tested-by: anthony <antdev66@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Lambertz <mail@thomaslambertz.de>
Cc: anthony <antdev66@gmail.com>
Cc: stable@vger.kernel.org
Fixes: 5f409e20b (x86/fpu: Defer FPU state load until return to userspace)
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
[Add a comment in front of the warning. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This reverts commit 240c35a378
("kvm: x86: Use task structs fpu field for user", 2018-11-06).
The commit is broken and causes QEMU's FPU state to be destroyed
when KVM_RUN is preempted.
Fixes: 240c35a378 ("kvm: x86: Use task structs fpu field for user")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Letting this pend may cause nested_get_vmcs12_pages to run against an
invalid state, corrupting the effective vmcs of L1.
This was triggerable in QEMU after a guest corruption in L2, followed by
a L1 reset.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Fixes: 7f7f1ba33c ("KVM: x86: do not load vmcs12 pages while still in SMM")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull core fixes from Thomas Gleixner:
- A collection of objtool fixes which address recent fallout partially
exposed by newer toolchains, clang, BPF and general code changes.
- Force USER_DS for user stack traces
[ Note: the "objtool fixes" are not all to objtool itself, but for
kernel code that triggers objtool warnings.
Things like missing function size annotations, or code that confuses
the unwinder etc. - Linus]
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
objtool: Support conditional retpolines
objtool: Convert insn type to enum
objtool: Fix seg fault on bad switch table entry
objtool: Support repeated uses of the same C jump table
objtool: Refactor jump table code
objtool: Refactor sibling call detection logic
objtool: Do frame pointer check before dead end check
objtool: Change dead_end_function() to return boolean
objtool: Warn on zero-length functions
objtool: Refactor function alias logic
objtool: Track original function across branches
objtool: Add mcsafe_handle_tail() to the uaccess safe list
bpf: Disable GCC -fgcse optimization for ___bpf_prog_run()
x86/uaccess: Remove redundant CLACs in getuser/putuser error paths
x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail()
x86/uaccess: Remove ELF function annotation from copy_user_handle_tail()
x86/head/64: Annotate start_cpu0() as non-callable
x86/entry: Fix thunk function ELF sizes
x86/kvm: Don't call kvm_spurious_fault() from .fixup
x86/kvm: Replace vmx_vmenter()'s call to kvm_spurious_fault() with UD2
...
Updates KVM_CAP_PMU_EVENT_FILTER so it can also whitelist or blacklist
fixed counters.
Signed-off-by: Eric Hankland <ehankland@google.com>
[No need to check padding fields for zero. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If a KVM guest is reset while running a nested guest, free_nested will
disable the shadow VMCS execution control in the vmcs01. However,
on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync
the VMCS12 to the shadow VMCS which has since been freed.
This causes a vmptrld of a NULL pointer on my machime, but Jan reports
the host to hang altogether. Let's see how much this trivial patch fixes.
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If a perf_event creation fails due to any reason of the host perf
subsystem, it has no chance to log the corresponding event for guest
which may cause abnormal sampling data in guest result. In debug mode,
this message helps to understand the state of vPMC and we may not
limit the number of occurrences but not in a spamming style.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When CPU raise #NPF on guest data access and guest CR4.SMAP=1, it is
possible that CPU microcode implementing DecodeAssist will fail
to read bytes of instruction which caused #NPF. This is AMD errata
1096 and it happens because CPU microcode reading instruction bytes
incorrectly attempts to read code as implicit supervisor-mode data
accesses (that is, just like it would read e.g. a TSS), which are
susceptible to SMAP faults. The microcode reads CS:RIP and if it is
a user-mode address according to the page tables, the processor
gives up and returns no instruction bytes. In this case,
GuestIntrBytes field of the VMCB on a VMEXIT will incorrectly
return 0 instead of the correct guest instruction bytes.
Current KVM code attemps to detect and workaround this errata, but it
has multiple issues:
1) It mistakenly checks if guest CR4.SMAP=0 instead of guest CR4.SMAP=1,
which is required for encountering a SMAP fault.
2) It assumes SMAP faults can only occur when guest CPL==3.
However, in case guest CR4.SMEP=0, the guest can execute an instruction
which reside in a user-accessible page with CPL<3 priviledge. If this
instruction raise a #NPF on it's data access, then CPU DecodeAssist
microcode will still encounter a SMAP violation. Even though no sane
OS will do so (as it's an obvious priviledge escalation vulnerability),
we still need to handle this semanticly correct in KVM side.
Note that (2) *is* a useful optimization, because CR4.SMAP=1 is an easy
triggerable condition and guests usually enable SMAP together with SMEP.
If the vCPU has CR4.SMEP=1, the errata could indeed be encountered onlt
at guest CPL==3; otherwise, the CPU would raise a SMEP fault to guest
instead of #NPF. We keep this condition to avoid false positives in
the detection of the errata.
In addition, to avoid future confusion and improve code readbility,
include details of the errata in code and not just in commit message.
Fixes: 05d5a48635 ("KVM: SVM: Workaround errata#1096 (insn_len maybe zero on SMAP violation)")
Cc: Singh Brijesh <brijesh.singh@amd.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Dedicated instances are currently disturbed by unnecessary jitter due
to the emulated lapic timers firing on the same pCPUs where the
vCPUs reside. There is no hardware virtual timer on Intel for guest
like ARM, so both programming timer in guest and the emulated timer fires
incur vmexits. This patch tries to avoid vmexit when the emulated timer
fires, at least in dedicated instance scenario when nohz_full is enabled.
In that case, the emulated timers can be offload to the nearest busy
housekeeping cpus since APICv has been found for several years in server
processors. The guest timer interrupt can then be injected via posted interrupts,
which are delivered by the housekeeping cpu once the emulated timer fires.
The host should tuned so that vCPUs are placed on isolated physical
processors, and with several pCPUs surplus for busy housekeeping.
If disabled mwait/hlt/pause vmexits keep the vCPUs in non-root mode,
~3% redis performance benefit can be observed on Skylake server, and the
number of external interrupt vmexits drops substantially. Without patch
VM-EXIT Samples Samples% Time% Min Time Max Time Avg time
EXTERNAL_INTERRUPT 42916 49.43% 39.30% 0.47us 106.09us 0.71us ( +- 1.09% )
While with patch:
VM-EXIT Samples Samples% Time% Min Time Max Time Avg time
EXTERNAL_INTERRUPT 6871 9.29% 2.96% 0.44us 57.88us 0.72us ( +- 4.02% )
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Objtool reports the following:
arch/x86/kvm/vmx/vmenter.o: warning: objtool: vmx_vmenter()+0x14: call without frame pointer save/setup
But frame pointers are necessarily broken anyway, because
__vmx_vcpu_run() clobbers RBP with the guest's value before calling
vmx_vmenter(). So calling without a frame pointer doesn't make things
any worse.
Make objtool happy by changing the call to a UD2.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/9fc2216c9dc972f95bb65ce2966a682c6bda1cb0.1563413318.git.jpoimboe@redhat.com
Some of the fastop functions, e.g. em_setcc(), are actually just used as
global labels which point to blocks of functions. The global labels are
incorrectly annotated as functions. Also the functions themselves don't
have size annotations.
Fixes a bunch of warnings like the following:
arch/x86/kvm/emulate.o: warning: objtool: seto() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: em_setcc() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: setno() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: setc() is missing an ELF size annotation
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/c8cc9be60ebbceb3092aa5dd91916039a1f88275.1563413318.git.jpoimboe@redhat.com
Commit 61abdbe0bc ("kvm: x86: make lapic hrtimer pinned") pinned the
lapic timer to avoid to wait until the next kvm exit for the guest to
see KVM_REQ_PENDING_TIMER set. There is another solution to give a kick
after setting the KVM_REQ_PENDING_TIMER bit, make lapic timer unpinned
will be used in follow up patches.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
To avoid semantic inconsistency, the fixed_counters in Intel vPMU
need to be reset to 0 in intel_pmu_reset() as gp_counters does.
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As reported by Maxime at
https://bugzilla.kernel.org/show_bug.cgi?id=204175:
In vmx/nested.c::get_vmx_mem_address(), when the guest runs in long mode,
the base address of the memory operand is computed with a simple:
*ret = s.base + off;
This is incorrect, the base applies only to FS and GS, not to the others.
Because of that, if the guest uses a VMX instruction based on DS and has
a DS.base that is non-zero, KVM wrongfully adds the base to the
resulting address.
Reported-by: Maxime Villard <max@m00nbsd.net>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The ioapic_debug and apic_debug have been not used
for years, and kvm tracepoints are enough for debugging,
so remove them as Paolo suggested.
However, there may be something wrong when pv evi get/put
user, so it's better to retain some log there.
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There are some pr_debug in TSC code, which may have
been no use, so remove them as Paolo suggested.
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This fixes the following coccinelle warning:
WARNING: return of 0/1 in function 'vmx_need_emulation_on_page_fault'
with return type bool
Return false instead of 0.
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
clang finds a contruct suspicious that converts an unsigned
character to a signed integer and back, causing an overflow:
arch/x86/kvm/mmu.c:4605:39: error: implicit conversion from 'int' to 'u8' (aka 'unsigned char') changes value from -205 to 51 [-Werror,-Wconstant-conversion]
u8 wf = (pfec & PFERR_WRITE_MASK) ? ~w : 0;
~~ ^~
arch/x86/kvm/mmu.c:4607:38: error: implicit conversion from 'int' to 'u8' (aka 'unsigned char') changes value from -241 to 15 [-Werror,-Wconstant-conversion]
u8 uf = (pfec & PFERR_USER_MASK) ? ~u : 0;
~~ ^~
arch/x86/kvm/mmu.c:4609:39: error: implicit conversion from 'int' to 'u8' (aka 'unsigned char') changes value from -171 to 85 [-Werror,-Wconstant-conversion]
u8 ff = (pfec & PFERR_FETCH_MASK) ? ~x : 0;
~~ ^~
Add an explicit cast to tell clang that everything works as
intended here.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://github.com/ClangBuiltLinux/linux/issues/95
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Clang notices a code path in which some variables are never
initialized, but fails to figure out that this can never happen
on i386 because is_64_bit_mode() always returns false.
arch/x86/kvm/hyperv.c:1610:6: error: variable 'ingpa' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
if (!longmode) {
^~~~~~~~~
arch/x86/kvm/hyperv.c:1632:55: note: uninitialized use occurs here
trace_kvm_hv_hypercall(code, fast, rep_cnt, rep_idx, ingpa, outgpa);
^~~~~
arch/x86/kvm/hyperv.c:1610:2: note: remove the 'if' if its condition is always true
if (!longmode) {
^~~~~~~~~~~~~~~
arch/x86/kvm/hyperv.c:1595:18: note: initialize the variable 'ingpa' to silence this warning
u64 param, ingpa, outgpa, ret = HV_STATUS_SUCCESS;
^
= 0
arch/x86/kvm/hyperv.c:1610:6: error: variable 'outgpa' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
arch/x86/kvm/hyperv.c:1610:6: error: variable 'param' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
Flip the condition around to avoid the conditional execution on i386.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
AVX512 BFLOAT16 instructions support 16-bit BFLOAT16 floating-point
format (BF16) for deep learning optimization.
Intel adds AVX512 BFLOAT16 feature in CooperLake, which is CPUID.7.1.EAX[5].
Detailed information of the CPUID bit can be found here,
https://software.intel.com/sites/default/files/managed/c5/15/\
architecture-instruction-set-extensions-programming-reference.pdf.
Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
[Fix type mismatch in min, changing constant "1" to "1u". - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* support for chained PMU counters in guests
* improved SError handling
* handle Neoverse N1 erratum #1349291
* allow side-channel mitigation status to be migrated
* standardise most AArch64 system register accesses to msr_s/mrs_s
* fix host MPIDR corruption on 32bit
* selftests ckleanups
x86:
* PMU event {white,black}listing
* ability for the guest to disable host-side interrupt polling
* fixes for enlightened VMCS (Hyper-V pv nested virtualization),
* new hypercall to yield to IPI target
* support for passing cstate MSRs through to the guest
* lots of cleanups and optimizations
Generic:
* Some txt->rST conversions for the documentation
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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:
- support for chained PMU counters in guests
- improved SError handling
- handle Neoverse N1 erratum #1349291
- allow side-channel mitigation status to be migrated
- standardise most AArch64 system register accesses to msr_s/mrs_s
- fix host MPIDR corruption on 32bit
- selftests ckleanups
x86:
- PMU event {white,black}listing
- ability for the guest to disable host-side interrupt polling
- fixes for enlightened VMCS (Hyper-V pv nested virtualization),
- new hypercall to yield to IPI target
- support for passing cstate MSRs through to the guest
- lots of cleanups and optimizations
Generic:
- Some txt->rST conversions for the documentation"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (128 commits)
Documentation: virtual: Add toctree hooks
Documentation: kvm: Convert cpuid.txt to .rst
Documentation: virtual: Convert paravirt_ops.txt to .rst
KVM: x86: Unconditionally enable irqs in guest context
KVM: x86: PMU Event Filter
kvm: x86: Fix -Wmissing-prototypes warnings
KVM: Properly check if "page" is valid in kvm_vcpu_unmap
KVM: arm/arm64: Initialise host's MPIDRs by reading the actual register
KVM: LAPIC: Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane
kvm: LAPIC: write down valid APIC registers
KVM: arm64: Migrate _elx sysreg accessors to msr_s/mrs_s
KVM: doc: Add API documentation on the KVM_REG_ARM_WORKAROUNDS register
KVM: arm/arm64: Add save/restore support for firmware workaround state
arm64: KVM: Propagate full Spectre v2 workaround state to KVM guests
KVM: arm/arm64: Support chained PMU counters
KVM: arm/arm64: Remove pmc->bitmask
KVM: arm/arm64: Re-create event when setting counter value
KVM: arm/arm64: Extract duplicated code to own function
KVM: arm/arm64: Rename kvm_pmu_{enable/disable}_counter functions
KVM: LAPIC: ARBPRI is a reserved register for x2APIC
...
The split low/high access is the only non-READ_ONCE version of gup_get_pte
that did show up in the various arch implemenations. Lift it to common
code and drop the ifdef based arch override.
Link: http://lkml.kernel.org/r/20190625143715.1689-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: James Hogan <jhogan@kernel.org>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
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Merge tag 'kvm-arm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm updates for 5.3
- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
On VMX, KVM currently does not re-enable irqs until after it has exited
the guest context. As a result, a tick that fires in the window between
VM-Exit and guest_exit_irqoff() will be accounted as system time. While
said window is relatively small, it's large enough to be problematic in
some configurations, e.g. if VM-Exits are consistently occurring a hair
earlier than the tick irq.
Intentionally toggle irqs back off so that guest_exit_irqoff() can be
used in lieu of guest_exit() in order to avoid the save/restore of flags
in guest_exit(). On my Haswell system, "nop; cli; sti" is ~6 cycles,
versus ~28 cycles for "pushf; pop <reg>; cli; push <reg>; popf".
Fixes: f2485b3e0c ("KVM: x86: use guest_exit_irqoff")
Reported-by: Wei Yang <w90p710@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some events can provide a guest with information about other guests or the
host (e.g. L3 cache stats); providing the capability to restrict access
to a "safe" set of events would limit the potential for the PMU to be used
in any side channel attacks. This change introduces a new VM ioctl that
sets an event filter. If the guest attempts to program a counter for
any blacklisted or non-whitelisted event, the kernel counter won't be
created, so any RDPMC/RDMSR will show 0 instances of that event.
Signed-off-by: Eric Hankland <ehankland@google.com>
[Lots of changes. All remaining bugs are probably mine. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We get a warning when build kernel W=1:
arch/x86/kvm/../../../virt/kvm/eventfd.c:48:1: warning: no previous prototype for ‘kvm_arch_irqfd_allowed’ [-Wmissing-prototypes]
kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
^
The reason is kvm_arch_irqfd_allowed() is declared in arch/x86/kvm/irq.h,
which is not included by eventfd.c. Considering kvm_arch_irqfd_allowed()
is a weakly defined function in eventfd.c, remove the declaration to
kvm_host.h can fix this.
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull x86 CPU feature updates from Thomas Gleixner:
"Updates for x86 CPU features:
- Support for UMWAIT/UMONITOR, which allows to use MWAIT and MONITOR
instructions in user space to save power e.g. in HPC workloads
which spin wait on synchronization points.
The maximum time a MWAIT can halt in userspace is controlled by the
kernel and can be adjusted by the sysadmin.
- Speed up the MTRR handling code on CPUs which support cache
self-snooping correctly.
On those CPUs the wbinvd() invocations can be omitted which speeds
up the MTRR setup by a factor of 50.
- Support for the new x86 vendor Zhaoxin who develops processors
based on the VIA Centaur technology.
- Prevent 'cat /proc/cpuinfo' from affecting isolated NOHZ_FULL CPUs
by sending IPIs to retrieve the CPU frequency and use the cached
values instead.
- The addition and late revert of the FSGSBASE support. The revert
was required as it turned out that the code still has hard to
diagnose issues. Yet another engineering trainwreck...
- Small fixes, cleanups, improvements and the usual new Intel CPU
family/model addons"
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
x86/fsgsbase: Revert FSGSBASE support
selftests/x86/fsgsbase: Fix some test case bugs
x86/entry/64: Fix and clean up paranoid_exit
x86/entry/64: Don't compile ignore_sysret if 32-bit emulation is enabled
selftests/x86: Test SYSCALL and SYSENTER manually with TF set
x86/mtrr: Skip cache flushes on CPUs with cache self-snooping
x86/cpu/intel: Clear cache self-snoop capability in CPUs with known errata
Documentation/ABI: Document umwait control sysfs interfaces
x86/umwait: Add sysfs interface to control umwait maximum time
x86/umwait: Add sysfs interface to control umwait C0.2 state
x86/umwait: Initialize umwait control values
x86/cpufeatures: Enumerate user wait instructions
x86/cpu: Disable frequency requests via aperfmperf IPI for nohz_full CPUs
x86/acpi/cstate: Add Zhaoxin processors support for cache flush policy in C3
ACPI, x86: Add Zhaoxin processors support for NONSTOP TSC
x86/cpu: Create Zhaoxin processors architecture support file
x86/cpu: Split Tremont based Atoms from the rest
Documentation/x86/64: Add documentation for GS/FS addressing mode
x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2
x86/cpu: Enable FSGSBASE on 64bit by default and add a chicken bit
...
Pull timer updates from Thomas Gleixner:
"The timer and timekeeping departement delivers:
Core:
- The consolidation of the VDSO code into a generic library including
the conversion of x86 and ARM64. Conversion of ARM and MIPS are en
route through the relevant maintainer trees and should end up in
5.4.
This gets rid of the unnecessary different copies of the same code
and brings all architectures on the same level of VDSO
functionality.
- Make the NTP user space interface more robust by restricting the
TAI offset to prevent undefined behaviour. Includes a selftest.
- Validate user input in the compat settimeofday() syscall to catch
invalid values which would be turned into valid values by a
multiplication overflow
- Consolidate the time accessors
- Small fixes, improvements and cleanups all over the place
Drivers:
- Support for the NXP system counter, TI davinci timer
- Move the Microsoft HyperV clocksource/events code into the
drivers/clocksource directory so it can be shared between x86 and
ARM64.
- Overhaul of the Tegra driver
- Delay timer support for IXP4xx
- Small fixes, improvements and cleanups as usual"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
time: Validate user input in compat_settimeofday()
timer: Document TIMER_PINNED
clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic
clocksource/drivers: Make Hyper-V clocksource ISA agnostic
MAINTAINERS: Fix Andy's surname and the directory entries of VDSO
hrtimer: Use a bullet for the returns bullet list
arm64: vdso: Fix compilation with clang older than 8
arm64: compat: Fix __arch_get_hw_counter() implementation
arm64: Fix __arch_get_hw_counter() implementation
lib/vdso: Make delta calculation work correctly
MAINTAINERS: Add entry for the generic VDSO library
arm64: compat: No need for pre-ARMv7 barriers on an ARMv8 system
arm64: vdso: Remove unnecessary asm-offsets.c definitions
vdso: Remove superfluous #ifdef __KERNEL__ in vdso/datapage.h
clocksource/drivers/davinci: Add support for clocksource
clocksource/drivers/davinci: Add support for clockevents
clocksource/drivers/tegra: Set up maximum-ticks limit properly
clocksource/drivers/tegra: Cycles can't be 0
clocksource/drivers/tegra: Restore base address before cleanup
clocksource/drivers/tegra: Add verbose definition for 1MHz constant
...
Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane which
can happen sporadically in product environment.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Replace a magic 64-bit mask with a list of valid registers, computing
the same mask in the end.
Suggested-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Linus Torvalds