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| author | Wanpeng Li <wanpengli@tencent.com> | 2022-04-26 01:25:51 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-05-25 05:07:09 -0400 |
| commit | e0ac535178ad32c2a4898e2309dcc49ad546e96e (patch) | |
| tree | 6099689e24e37fab4612ef2e949b26424ca71ffa /arch | |
| parent | 6ba1e04fa60787ced4c9049cf7bd6cd0f1b80764 (diff) | |
| download | linux-e0ac535178ad32c2a4898e2309dcc49ad546e96e.tar.bz2 | |
KVM: LAPIC: Trace LAPIC timer expiration on every vmentry
In commit ec0671d5684a ("KVM: LAPIC: Delay trace_kvm_wait_lapic_expire
tracepoint to after vmexit", 2019-06-04), trace_kvm_wait_lapic_expire
was moved after guest_exit_irqoff() because invoking tracepoints within
kvm_guest_enter/kvm_guest_exit caused a lockdep splat.
These days this is not necessary, because commit 87fa7f3e98a1 ("x86/kvm:
Move context tracking where it belongs", 2020-07-09) restricted
the RCU extended quiescent state to be closer to vmentry/vmexit.
Moving the tracepoint back to __kvm_wait_lapic_expire is more accurate,
because it will be reported even if vcpu_enter_guest causes multiple
vmentries via the IPI/Timer fast paths, and it allows the removal of
advance_expire_delta.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1650961551-38390-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/lapic.h | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 8 |
3 files changed, 2 insertions, 11 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 66b0eb0bda94..a4e9eb329e42 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1648,10 +1648,10 @@ static void __kvm_wait_lapic_expire(struct kvm_vcpu *vcpu) tsc_deadline = apic->lapic_timer.expired_tscdeadline; apic->lapic_timer.expired_tscdeadline = 0; guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc()); - apic->lapic_timer.advance_expire_delta = guest_tsc - tsc_deadline; + trace_kvm_wait_lapic_expire(vcpu->vcpu_id, guest_tsc - tsc_deadline); if (lapic_timer_advance_dynamic) { - adjust_lapic_timer_advance(vcpu, apic->lapic_timer.advance_expire_delta); + adjust_lapic_timer_advance(vcpu, guest_tsc - tsc_deadline); /* * If the timer fired early, reread the TSC to account for the * overhead of the above adjustment to avoid waiting longer diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 4e4f8a22754f..65bb2a8cf145 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -38,7 +38,6 @@ struct kvm_timer { u64 tscdeadline; u64 expired_tscdeadline; u32 timer_advance_ns; - s64 advance_expire_delta; atomic_t pending; /* accumulated triggered timers */ bool hv_timer_in_use; }; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 476ea099ebf0..8b62c9b7795e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10310,14 +10310,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) */ guest_timing_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(); |