From 2b110b61644a34e97c92ae20788cbcb42d474fa9 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 17 Mar 2020 12:53:54 -0700 Subject: KVM: x86: Add blurb to CPUID tracepoint when using max basic leaf values Tack on "used max basic" at the end of the CPUID tracepoint when the output values correspond to the max basic leaf, i.e. when emulating Intel's out-of-range CPUID behavior. Observing "cpuid entry not found" in the tracepoint with non-zero output values is confusing for users that aren't familiar with the out-of-range semantics, and qualifying the "not found" case hopefully makes it clear that "found" means "found the exact entry". Suggested-by: Jan Kiszka Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/cpuid.c | 9 ++++++--- arch/x86/kvm/trace.h | 11 +++++++---- 2 files changed, 13 insertions(+), 7 deletions(-) (limited to 'arch') diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 2de721f3c420..990c76f34b03 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -990,13 +990,15 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, { u32 orig_function = *eax, function = *eax, index = *ecx; struct kvm_cpuid_entry2 *entry; - bool exact; + bool exact, used_max_basic = false; entry = kvm_find_cpuid_entry(vcpu, function, index); exact = !!entry; - if (!entry && !exact_only) + if (!entry && !exact_only) { entry = get_out_of_range_cpuid_entry(vcpu, &function, index); + used_max_basic = !!entry; + } if (entry) { *eax = entry->eax; @@ -1026,7 +1028,8 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, } } } - trace_kvm_cpuid(orig_function, index, *eax, *ebx, *ecx, *edx, exact); + trace_kvm_cpuid(orig_function, index, *eax, *ebx, *ecx, *edx, exact, + used_max_basic); return exact; } EXPORT_SYMBOL_GPL(kvm_cpuid); diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h index 27270ba0f05f..c3d1e9f4a2c0 100644 --- a/arch/x86/kvm/trace.h +++ b/arch/x86/kvm/trace.h @@ -153,8 +153,8 @@ TRACE_EVENT(kvm_fast_mmio, TRACE_EVENT(kvm_cpuid, TP_PROTO(unsigned int function, unsigned int index, unsigned long rax, unsigned long rbx, unsigned long rcx, unsigned long rdx, - bool found), - TP_ARGS(function, index, rax, rbx, rcx, rdx, found), + bool found, bool used_max_basic), + TP_ARGS(function, index, rax, rbx, rcx, rdx, found, used_max_basic), TP_STRUCT__entry( __field( unsigned int, function ) @@ -164,6 +164,7 @@ TRACE_EVENT(kvm_cpuid, __field( unsigned long, rcx ) __field( unsigned long, rdx ) __field( bool, found ) + __field( bool, used_max_basic ) ), TP_fast_assign( @@ -174,12 +175,14 @@ TRACE_EVENT(kvm_cpuid, __entry->rcx = rcx; __entry->rdx = rdx; __entry->found = found; + __entry->used_max_basic = used_max_basic; ), - TP_printk("func %x idx %x rax %lx rbx %lx rcx %lx rdx %lx, cpuid entry %s", + TP_printk("func %x idx %x rax %lx rbx %lx rcx %lx rdx %lx, cpuid entry %s%s", __entry->function, __entry->index, __entry->rax, __entry->rbx, __entry->rcx, __entry->rdx, - __entry->found ? "found" : "not found") + __entry->found ? "found" : "not found", + __entry->used_max_basic ? ", used max basic" : "") ); #define AREG(x) { APIC_##x, "APIC_" #x } -- cgit v1.2.3-58-ga151