perf/x86/lbr: Reset LBR_SELECT during vlbr reset

Wanpeng Li · Peter Zijlstra · commit 0fe39a3929ac · 2021-11-11T13:09:34.000+01:00
lbr_select in kvm guest has residual data even if kvm guest is poweroff. We can get residual data in the next boot. Because lbr_select is not reset during kvm vlbr release. Let's reset LBR_SELECT during vlbr reset. Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/1636096851-36623-1-git-send-email-wanpengli@tencent.com
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
@@ -265,6 +265,8 @@ void intel_pmu_lbr_reset(void)
 
 	cpuc->last_task_ctx = NULL;
 	cpuc->last_log_id = 0;
+	if (!static_cpu_has(X86_FEATURE_ARCH_LBR) && cpuc->lbr_select)
+		wrmsrl(MSR_LBR_SELECT, 0);
 }
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -265,6 +265,8 @@ void intel_pmu_lbr_reset(void)`
`265`	`265`
`266`	`266`	`cpuc->last_task_ctx = NULL;`
`267`	`267`	`cpuc->last_log_id = 0;`
	`268`	`+ if (!static_cpu_has(X86_FEATURE_ARCH_LBR) && cpuc->lbr_select)`
	`269`	`+ wrmsrl(MSR_LBR_SELECT, 0);`
`268`	`270`	`}`
`269`	`271`
`270`	`272`	`/*`