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 <wanpengli@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Wanpeng Li <wanpengli@tencent.com>
Link: https://lore.kernel.org/r/20211103091716.59906-1-likexu@tencent.com

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 603964408d2d7eacf079ef5115673f603ec735ed..42cf01ecdd131753af53560f9ee745078d6c93e1 100644 (file)
--- 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;
 }