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 <jan.kiszka@siemens.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 2de721f..990c76f 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);