KVM: LAPIC: Delay trace_kvm_wait_lapic_expire tracepoint to after vmexit

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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 8b89fe1f6c ("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>

...

This commit is contained in:

Wanpeng Li 2019-05-20 16:18:08 +08:00 • committed by Paolo Bonzini

parent 84ea3acaa0

commit ec0671d568

3 changed files with 15 additions and 7 deletions

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14

arch/x86/kvm/lapic.c

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1

arch/x86/kvm/lapic.h

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arch/x86/kvm/x86.c

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