Messages in this thread | | | Subject | Re: [PATCH 5/6] KVM: x86: Rename "found" variable in kvm_cpuid() to "exact_entry_exists" | From | Jan Kiszka <> | Date | Mon, 2 Mar 2020 21:48:26 +0100 |
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On 02.03.20 21:35, Sean Christopherson wrote: > On Mon, Mar 02, 2020 at 09:20:52PM +0100, Jan Kiszka wrote: >> On 02.03.20 20:57, Sean Christopherson wrote: >>> Rename "found" in kvm_cpuid() to "exact_entry_exists" to better convey >>> that the intent of the tracepoint's "found/not found" output is to trace >>> whether the output values are for the actual requested leaf or for some >>> other (likely unrelated) leaf that was found while processing entries to >>> emulate funky CPU behavior, e.g. the max basic leaf on Intel CPUs when >>> the requested CPUID leaf is out of range. >>> >>> Suggested-by: Jan Kiszka <jan.kiszka@siemens.com> >>> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> >>> --- >>> arch/x86/kvm/cpuid.c | 6 +++--- >>> 1 file changed, 3 insertions(+), 3 deletions(-) >>> >>> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c >>> index 869526930cf7..b0a4f3c17932 100644 >>> --- a/arch/x86/kvm/cpuid.c >>> +++ b/arch/x86/kvm/cpuid.c >>> @@ -1002,10 +1002,10 @@ void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, >>> { >>> const u32 function = *eax, index = *ecx; >>> struct kvm_cpuid_entry2 *entry; >>> - bool found; >>> + bool exact_entry_exists; >>> entry = kvm_find_cpuid_entry(vcpu, function, index); >>> - found = entry; >>> + exact_entry_exists = !!entry; >>> /* >>> * Intel CPUID semantics treats any query for an out-of-range >>> * leaf as if the highest basic leaf (i.e. CPUID.0H:EAX) were >>> @@ -1047,7 +1047,7 @@ void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, >>> } >>> } >>> } >>> - trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx, found); >>> + trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx, exact_entry_exists); >> >> Actually, I think we also what to change output in the tracepoint. > > Oh, I definitely want to change it, but AIUI it's ABI and shouldn't be > changed. Paolo? >
This can be discovered via the format string in sysfs and handled by the consumer. But I'm not an expert in the tracing ABI.
Jan
-- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux
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