| Message ID | 20240306230153.786365-2-seanjc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/pmu: PEBS fixes and new testcases | expand |
On 3/7/2024 7:01 AM, Sean Christopherson wrote: > Enabling PEBS for fixed counters is only allowed if "Extended PEBS" is > supported, and unfortunately "Extended PEBS" is bundled with a pile of > other PEBS features under the "Baseline" umbrella. KVM emulates this > correctly and disallows enabling PEBS on fixed counters if the vCPU > doesn't have Baseline PEBS support. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > x86/pmu_pebs.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/x86/pmu_pebs.c b/x86/pmu_pebs.c > index f7b52b90..050617cd 100644 > --- a/x86/pmu_pebs.c > +++ b/x86/pmu_pebs.c > @@ -356,13 +356,13 @@ static void check_pebs_counters(u64 pebs_data_cfg) > unsigned int idx; > u64 bitmask = 0; > > - for (idx = 0; idx < pmu.nr_fixed_counters; idx++) > + for (idx = 0; has_baseline && idx < pmu.nr_fixed_counters; idx++) > check_one_counter(FIXED, idx, pebs_data_cfg); > > for (idx = 0; idx < max_nr_gp_events; idx++) > check_one_counter(GP, idx, pebs_data_cfg); > > - for (idx = 0; idx < pmu.nr_fixed_counters; idx++) > + for (idx = 0; has_baseline && idx < pmu.nr_fixed_counters; idx++) > bitmask |= BIT_ULL(FIXED_CNT_INDEX + idx); > for (idx = 0; idx < max_nr_gp_events; idx += 2) > bitmask |= BIT_ULL(idx); Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
diff --git a/x86/pmu_pebs.c b/x86/pmu_pebs.c index f7b52b90..050617cd 100644 --- a/x86/pmu_pebs.c +++ b/x86/pmu_pebs.c @@ -356,13 +356,13 @@ static void check_pebs_counters(u64 pebs_data_cfg) unsigned int idx; u64 bitmask = 0; - for (idx = 0; idx < pmu.nr_fixed_counters; idx++) + for (idx = 0; has_baseline && idx < pmu.nr_fixed_counters; idx++) check_one_counter(FIXED, idx, pebs_data_cfg); for (idx = 0; idx < max_nr_gp_events; idx++) check_one_counter(GP, idx, pebs_data_cfg); - for (idx = 0; idx < pmu.nr_fixed_counters; idx++) + for (idx = 0; has_baseline && idx < pmu.nr_fixed_counters; idx++) bitmask |= BIT_ULL(FIXED_CNT_INDEX + idx); for (idx = 0; idx < max_nr_gp_events; idx += 2) bitmask |= BIT_ULL(idx);
Enabling PEBS for fixed counters is only allowed if "Extended PEBS" is supported, and unfortunately "Extended PEBS" is bundled with a pile of other PEBS features under the "Baseline" umbrella. KVM emulates this correctly and disallows enabling PEBS on fixed counters if the vCPU doesn't have Baseline PEBS support. Signed-off-by: Sean Christopherson <seanjc@google.com> --- x86/pmu_pebs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)