From 0fe39a3929ac7af980347814d552a734b51adacf Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Fri, 5 Nov 2021 00:20:51 -0700 Subject: [PATCH] perf/x86/lbr: Reset LBR_SELECT during vlbr reset 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 Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/1636096851-36623-1-git-send-email-wanpengli@tencent.com --- arch/x86/events/intel/lbr.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index 6b72e9b55c69..8043213b75a5 100644 --- 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); } /*