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| author | Wanpeng Li <wanpengli@tencent.com> | 2019-05-20 11:18:08 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-06-04 20:27:29 +0300 |
| commit | ec0671d5684aca3326269439398e47790f1c6e7e (patch) | |
| tree | 16963753d67a0d30668fe02a774be1d194115e33 /arch/x86/kvm/x86.c | |
| parent | 84ea3acaa01fb90861b341038998e27a5198e1a0 (diff) | |
| download | linux-ec0671d5684aca3326269439398e47790f1c6e7e.tar.xz | |
KVM: LAPIC: Delay trace_kvm_wait_lapic_expire tracepoint to after vmexit
wait_lapic_expire() call was moved above guest_enter_irqoff() because of
its tracepoint, which violated the RCU extended quiescent state invoked
by guest_enter_irqoff()[1][2]. This patch simply moves the tracepoint
below guest_exit_irqoff() in vcpu_enter_guest(). Snapshot the delta before
VM-Enter, but trace it after VM-Exit. This can help us to move
wait_lapic_expire() just before vmentry in the later patch.
[1] Commit 8b89fe1f6c43 ("kvm: x86: move tracepoints outside extended quiescent state")
[2] https://patchwork.kernel.org/patch/7821111/
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
[Track whether wait_lapic_expire was called, and do not invoke the tracepoint
if not. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f3c0f2b63d76..7a26aa5b0861 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7980,6 +7980,13 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) ++vcpu->stat.exits; guest_exit_irqoff(); + if (lapic_in_kernel(vcpu)) { + s64 delta = vcpu->arch.apic->lapic_timer.advance_expire_delta; + if (delta != S64_MIN) { + trace_kvm_wait_lapic_expire(vcpu->vcpu_id, delta); + vcpu->arch.apic->lapic_timer.advance_expire_delta = S64_MIN; + } + } local_irq_enable(); preempt_enable(); |