If PMU counter has PEBS enabled it is not enough to disable counter
on a guest entry since PEBS memory write can overshoot guest entry
and corrupt guest memory. Disabling PEBS during guest entry solves
the problem.
Tested-by: David Ahern <dsah...@gmail.com>
Signed-off-by: Gleb Natapov <g...@redhat.com>
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c
b/arch/x86/kernel/cpu/perf_event_intel.c
index 7a8b9d0..7268fd8 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1444,8 +1444,16 @@ static struct perf_guest_switch_msr
*intel_guest_get_msrs(int *nr)
arr[0].msr = MSR_CORE_PERF_GLOBAL_CTRL;
arr[0].host = x86_pmu.intel_ctrl & ~cpuc->intel_ctrl_guest_mask;
arr[0].guest = x86_pmu.intel_ctrl & ~cpuc->intel_ctrl_host_mask;
+ /*
+ * If PMU counter has PEBS enabled it is not enough to disable counter
+ * on a guest entry since PEBS memory write can overshoot guest entry
+ * and corrupt guest memory. Disabling PEBS solves the problem.
+ */
+ arr[1].msr = MSR_IA32_PEBS_ENABLE;
+ arr[1].host = cpuc->pebs_enabled;
+ arr[1].guest = 0;
- *nr = 1;
+ *nr = 2;
return arr;
}
--
Gleb.
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