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.
> + pmc->eventsel = (intel_arch_events[event].unit_mask << 8) |
> + intel_arch_events[event].eventsel;
> + }
> +}
> +
[Every now and then, gmail likes to revert your plain text setting,
just to keep you on your toes!]
