Re: [PATCH v8 4/5] KVM: selftests: Add a helper to query enable_mediated_pmu module param

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] kvm_is_mediated_pmu_enabled() incorrectly queries the kvm_amd module on Centaur and Zhaoxin CPUs, causing tests to needlessly skip.
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commit f89432ff2f99beb9b018032f8161522a25f18627
Author: Sean Christopherson <seanjc@google.com>

KVM: selftests: Add a helper to query enable_mediated_pmu module param

This commit adds a utility function to check if the mediated PMU is enabled
by querying the vendor-specific KVM module parameter.

> diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h
> --- a/tools/testing/selftests/kvm/include/x86/processor.h
> +++ b/tools/testing/selftests/kvm/include/x86/processor.h

[ ... ]

> +static inline bool kvm_is_mediated_pmu_enabled(void)
> +{
> +	if (host_cpu_is_intel)
> +		return get_kvm_intel_param_bool("enable_mediated_pmu");
> +
> +	return get_kvm_amd_param_bool("enable_mediated_pmu");

[Severity: Medium]
Will this cause tests to needlessly skip on Centaur and Zhaoxin CPUs?

Since host_cpu_is_intel only evaluates to true for GenuineIntel CPUs,
VMX-compatible CPUs like Centaur and Zhaoxin will fall through and call
get_kvm_amd_param_bool("enable_mediated_pmu").

Because those platforms use the kvm_intel module, querying the kvm_amd
parameters will result in a missing file (ENOENT), which aborts the
execution with a ksft_exit_skip().

Would it be safer to pivot on host_cpu_is_amd_compatible to check AMD,
and then fall back to Intel for everything else?

> +}
> +
>  static inline bool kvm_is_forced_emulation_enabled(void)
>  {

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Sashiko AI review · https://sashiko.dev/#/patchset/20260610003030.2957261-1-seanjc@google.com?part=4