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| author | Lorenzo Brescia <lorenzo.brescia@edu.unito.it> | 2020-12-23 17:45:07 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-01-26 02:52:08 +0300 |
| commit | d95df9510679757bdfc22376d351cdf367b3a604 (patch) | |
| tree | bc191b86ea2a8ef698470f38ccd91b4711eecd5a /arch | |
| parent | 01ead84ccd23afadebe66aea0eda002ac29ca9be (diff) | |
| download | linux-d95df9510679757bdfc22376d351cdf367b3a604.tar.xz | |
kvm: tracing: Fix unmatched kvm_entry and kvm_exit events
On VMX, if we exit and then re-enter immediately without leaving
the vmx_vcpu_run() function, the kvm_entry event is not logged.
That means we will see one (or more) kvm_exit, without its (their)
corresponding kvm_entry, as shown here:
CPU-1979 [002] 89.871187: kvm_entry: vcpu 1
CPU-1979 [002] 89.871218: kvm_exit: reason MSR_WRITE
CPU-1979 [002] 89.871259: kvm_exit: reason MSR_WRITE
It also seems possible for a kvm_entry event to be logged, but then
we leave vmx_vcpu_run() right away (if vmx->emulation_required is
true). In this case, we will have a spurious kvm_entry event in the
trace.
Fix these situations by moving trace_kvm_entry() inside vmx_vcpu_run()
(where trace_kvm_exit() already is).
A trace obtained with this patch applied looks like this:
CPU-14295 [000] 8388.395387: kvm_entry: vcpu 0
CPU-14295 [000] 8388.395392: kvm_exit: reason MSR_WRITE
CPU-14295 [000] 8388.395393: kvm_entry: vcpu 0
CPU-14295 [000] 8388.395503: kvm_exit: reason EXTERNAL_INTERRUPT
Of course, not calling trace_kvm_entry() in common x86 code any
longer means that we need to adjust the SVM side of things too.
Signed-off-by: Lorenzo Brescia <lorenzo.brescia@edu.unito.it>
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
Message-Id: <160873470698.11652.13483635328769030605.stgit@Wayrath>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 3 |
3 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 7ef171790d02..f923e14e87df 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3739,6 +3739,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); + trace_kvm_entry(vcpu); + svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX]; svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP]; svm->vmcb->save.rip = vcpu->arch.regs[VCPU_REGS_RIP]; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 2af05d3b0590..cc60b1fc3ee7 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6653,6 +6653,8 @@ reenter_guest: if (vmx->emulation_required) return EXIT_FASTPATH_NONE; + trace_kvm_entry(vcpu); + if (vmx->ple_window_dirty) { vmx->ple_window_dirty = false; vmcs_write32(PLE_WINDOW, vmx->ple_window); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9025c7673af6..1f64e8b97605 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8992,8 +8992,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_x86_ops.request_immediate_exit(vcpu); } - trace_kvm_entry(vcpu); - fpregs_assert_state_consistent(); if (test_thread_flag(TIF_NEED_FPU_LOAD)) switch_fpu_return(); @@ -11560,6 +11558,7 @@ int kvm_sev_es_string_io(struct kvm_vcpu *vcpu, unsigned int size, } EXPORT_SYMBOL_GPL(kvm_sev_es_string_io); +EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_entry); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_fast_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq); |