[PATCH] perf/x86/vlbr: Add c->flags to vlbr event constraints

From: Like Xu
Date: Wed Nov 03 2021 - 05:17:28 EST


From: Like Xu <likexu@xxxxxxxxxxx>

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.

Reported-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Fixes: 097e4311cda9 ("perf/x86: Add constraint to create guest LBR event without hw counter")
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
arch/x86/events/intel/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 7011e87be6d0..30b5d1b3cb03 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2997,8 +2997,10 @@ 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;
}
--
2.33.0