From 0fe39a3929ac7af980347814d552a734b51adacf Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Fri, 5 Nov 2021 00:20:51 -0700 Subject: 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(+) (limited to 'arch') 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); } /* -- cgit v1.2.3 From 5863702561e625903ec678551cb056a4b19e0b8a Mon Sep 17 00:00:00 2001 From: Like Xu Date: Wed, 3 Nov 2021 17:17:16 +0800 Subject: perf/x86/vlbr: Add c->flags to vlbr event constraints Just like what we do in the x86_get_event_constraints(), the PERF_X86_EVENT_LBR_SELECT flag should also be propagated to event->hw.flags so that the host lbr driver can save/restore MSR_LBR_SELECT for the special vlbr event created by KVM or BPF. Fixes: 097e4311cda9 ("perf/x86: Add constraint to create guest LBR event without hw counter") Reported-by: Wanpeng Li Signed-off-by: Like Xu Signed-off-by: Peter Zijlstra (Intel) Tested-by: Wanpeng Li Link: https://lore.kernel.org/r/20211103091716.59906-1-likexu@tencent.com --- arch/x86/events/intel/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 603964408d2d..42cf01ecdd13 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3048,8 +3048,10 @@ intel_vlbr_constraints(struct perf_event *event) { struct event_constraint *c = &vlbr_constraint; - if (unlikely(constraint_match(c, event->hw.config))) + if (unlikely(constraint_match(c, event->hw.config))) { + event->hw.flags |= c->flags; return c; + } return NULL; } -- cgit v1.2.3