Messages in this thread | | | Date | Thu, 9 Dec 2021 20:24:34 +0100 | Subject | Re: [PATCH v2 2/6] KVM: x86/pmu: Refactoring find_arch_event() to pmc_perf_hw_id() | From | Paolo Bonzini <> |
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On 12/9/21 04:52, Jim Mattson wrote: > Why don't we just use PERF_TYPE_RAW for guest counters all of the > time? What is the advantage of matching entries in a table so that we > can use PERF_TYPE_HARDWARE?
In theory it's so that hosts without support for architectural PMU events can map the architectural PMU events to their own. In practice, we can probably return early from intel_pmu_refresh if the host does not support X86_FEATURE_ARCH_PERFMON, because only the oldest Pentium 4 toasters^Wprocessors probably have VMX but lack architectural PMU.
Paolo
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