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    Subject[kvm-unit-tests Patch v4 05/17] x86: pmu: Enlarge cnt[] length to 48 in check_counters_many()
    Date
    Considering there are already 8 GP counters and 4 fixed counters on
    latest Intel processors, like Sapphire Rapids. The original cnt[] array
    length 10 is definitely not enough to cover all supported PMU counters on
    these new processors even through currently KVM only supports 3 fixed
    counters at most. This would cause out of bound memory access and may trigger
    false alarm on PMU counter validation

    It's probably more and more GP and fixed counters are introduced in the
    future and then directly extends the cnt[] array length to 48 once and
    for all. Base on the layout of IA32_PERF_GLOBAL_CTRL and
    IA32_PERF_GLOBAL_STATUS, 48 looks enough in near feature.

    Reviewed-by: Jim Mattson <jmattson@google.com>
    Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
    ---
    x86/pmu.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/x86/pmu.c b/x86/pmu.c
    index 5fd7439a0eba..494af4012e84 100644
    --- a/x86/pmu.c
    +++ b/x86/pmu.c
    @@ -253,7 +253,7 @@ static void check_fixed_counters(void)

    static void check_counters_many(void)
    {
    - pmu_counter_t cnt[10];
    + pmu_counter_t cnt[48];
    int i, n;

    for (i = 0, n = 0; n < pmu.nr_gp_counters; i++) {
    --
    2.34.1

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