Rename the tracepoint function from trace_kvm_async_pf_doublefault() to trace_kvm_async_pf_repeated_fault() to make it clear, since double fault has nothing to do with this trace function. Asynchronous Page Fault (APF) is an artifact generated by KVM when it cannot find a physical page to satisfy an EPT violation. KVM uses APF to tell the guest OS to do something else such as scheduling other guest processes to make forward progress. However, when another guest process also touches a previously APFed page, KVM halts the vCPU instead of generating a repeated APF to avoid wasting cycles. Double fault (#DF) clearly has a different meaning and a different consequence when triggered. #DF requires two nested contributory exceptions instead of two page faults faulting at the same address. A prevous bug on APF indicates that it may trigger a double fault in the guest [1] and clearly this trace function has nothing to do with it. So rename this function should be a valid choice. No functional change intended. [1] https://www.spinics.net/lists/kvm/msg214957.html Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx> --- arch/x86/kvm/mmu/mmu.c | 2 +- include/trace/events/kvm.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 06ac8c7cef67..0004ec68fc5c 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4164,7 +4164,7 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) if (!fault->prefetch && kvm_can_do_async_pf(vcpu)) { trace_kvm_try_async_get_page(fault->addr, fault->gfn); if (kvm_find_async_pf_gfn(vcpu, fault->gfn)) { - trace_kvm_async_pf_doublefault(fault->addr, fault->gfn); + trace_kvm_async_pf_repeated_fault(fault->addr, fault->gfn); kvm_make_request(KVM_REQ_APF_HALT, vcpu); return RET_PF_RETRY; } else if (kvm_arch_setup_async_pf(vcpu, fault->addr, fault->gfn)) { diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h index 37e1e1a2d67d..3bd31ea23fee 100644 --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -282,7 +282,7 @@ DEFINE_EVENT(kvm_async_get_page_class, kvm_try_async_get_page, TP_ARGS(gva, gfn) ); -DEFINE_EVENT(kvm_async_get_page_class, kvm_async_pf_doublefault, +DEFINE_EVENT(kvm_async_get_page_class, kvm_async_pf_repeated_fault, TP_PROTO(u64 gva, u64 gfn), base-commit: 1612c382ffbdf1f673caec76502b1c00e6d35363 -- 2.37.1.559.g78731f0fdb-goog
