[PATCH RFC 3/8] perf: x86/core: Snyc PERF_METRICS bit together with fixed counter3

From: Like Xu
Date: Mon Dec 12 2022 - 07:59:39 EST


From: Like Xu <likexu@xxxxxxxxxxx>

When the guest uses topdown (the fixed counter 3 and perf_metrics msr),
the sharing rule on the PERF_METRICS bit on the GLOBAL_CTRL msr does
not change, that is, it should be updated synchronously with the fixed
counter 3. Considering that guest topdown feature has just been enabled,
this is not a strictly bug fix.

Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: linux-perf-users@xxxxxxxxxxxxxxx
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
arch/x86/events/intel/core.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 1b92bf05fd65..e7897fd9f7ab 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2436,6 +2436,8 @@ static void intel_pmu_disable_fixed(struct perf_event *event)
*/
if (*(u64 *)cpuc->active_mask & INTEL_PMC_OTHER_TOPDOWN_BITS(idx))
return;
+
+ intel_clear_masks(event, GLOBAL_CTRL_EN_PERF_METRICS);
idx = INTEL_PMC_IDX_FIXED_SLOTS;
}

@@ -2729,6 +2731,7 @@ static void intel_pmu_enable_fixed(struct perf_event *event)
if (*(u64 *)cpuc->active_mask & INTEL_PMC_OTHER_TOPDOWN_BITS(idx))
return;

+ intel_set_masks(event, GLOBAL_CTRL_EN_PERF_METRICS);
idx = INTEL_PMC_IDX_FIXED_SLOTS;
}

--
2.38.2