On 7/12/2021 3:50 am, Jim Mattson wrote:
On Mon, Nov 29, 2021 at 11:42 PM Like Xu <like.xu.linux@xxxxxxxxx> wrote:From: Like Xu <likexu@xxxxxxxxxxx> The current pmc->eventsel for fixed counter is underutilised. The pmc->eventsel can be setup for all known available fixed counters since we have mapping between fixed pmc index and the intel_arch_events array. Either gp or fixed counter, it will simplify the later checks for consistency between eventsel and perf_hw_id. Signed-off-by: Like Xu <likexu@xxxxxxxxxxx> --- arch/x86/kvm/vmx/pmu_intel.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 1b7456b2177b..b7ab5fd03681 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -459,6 +459,21 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; } +static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu) +{ + size_t size = ARRAY_SIZE(fixed_pmc_events); + struct kvm_pmc *pmc; + u32 event; + int i; + + for (i = 0; i < pmu->nr_arch_fixed_counters; i++) { + pmc = &pmu->fixed_counters[i]; + event = fixed_pmc_events[array_index_nospec(i, size)];How do we know that i < size? For example, Ice Lake supports 4 fixed counters, but fixed_pmc_events only has three entries.
With the help of macro MAX_FIXED_COUNTERS, the fourth or more fixed counter is currently not supported in KVM. If the user space sets a super set of CPUID supported by KVM, any pmu emulation failure is to be expected, right ? Waiting for more comments from you on this patch set.
+ pmc->eventsel = (intel_arch_events[event].unit_mask << 8) | + intel_arch_events[event].eventsel; + } +} +
