This shortlog is flat out wrong. This patch does not add X86_FEATURE_PERFMON_V2, it adds a KVM-only leaf to redirect X86_FEATURE_PERFMON_V2 to its architectural location when KVM queries the leaf, e.g. via guest_cpuid_has(). On Tue, Feb 14, 2023, Like Xu wrote: > From: Like Xu <likexu@xxxxxxxxxxx> > > Considering that the core kernel may also want to know this flag, to avoid Please write changelogs so that they do not depend on the shortlog for context. I know the tip maintainers in particular like to make the changelog a continuation of the shortlog, but I find it really annoying, especially when reviewing in mutt, e.g. as I'm typing this, I don't even have the shortlog visible. In the vast majority of cases, being more explicit rarely adds more than a few chars, e.g. you'll save more by reducing the fluff in this changelog. > confusion this needs to be a scattered flag rather than a pure KVM flag so > that KVM can redirect it to the hardware-defined bit position, which is the > role of __feature_translate() and KVM_X86_FEATURE_PERFMON_V2. Like the shortlog, the changelog is best misleading, X86_FEATURE_PERFMON_V2 is already a scattered flag. Define a KVM-only leaf for AMD's PerfMonV2 feature flag to redirect the kernel's scattered version to its architectural location, e.g. so that KVM can query guest support via guest_cpuid_has().
