[PATCH] perf kvm: Fix arm64 VM-exit duration accounting

[PATCH] perf kvm: Fix arm64 VM-exit duration accounting

[lirongqing]

From: Li RongQing <lirongqing@baidu.com>

Use kvm_exit as the start event and the following kvm_entry as the
end event for arm64 VM-exit statistics. Keep decoding ret and esr_ec
from the exit sample.

Before this change, arm64 measured guest runtime as VM-exit time.

Fixes: 1218838d68f5 ("perf kvm: Add kvm-stat for arm64")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 tools/perf/util/kvm-stat-arch/kvm-stat-arm64.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/kvm-stat-arch/kvm-stat-arm64.c b/tools/perf/util/kvm-stat-arch/kvm-stat-arm64.c
index 018b0db..ff853ef 100644
--- a/tools/perf/util/kvm-stat-arch/kvm-stat-arm64.c
+++ b/tools/perf/util/kvm-stat-arch/kvm-stat-arm64.c
@@ -36,13 +36,7 @@ static void event_get_key(struct perf_sample *sample,
 }
 
 static bool event_begin(struct perf_sample *sample,
-			struct event_key *key __maybe_unused)
-{
-	return evsel__name_is(sample->evsel, kvm_entry_trace(EM_AARCH64));
-}
-
-static bool event_end(struct perf_sample *sample,
-		      struct event_key *key)
+			struct event_key *key)
 {
 	if (evsel__name_is(sample->evsel, kvm_exit_trace(EM_AARCH64))) {
 		event_get_key(sample, key);
@@ -51,6 +45,12 @@ static bool event_end(struct perf_sample *sample,
 	return false;
 }
 
+static bool event_end(struct perf_sample *sample,
+		      struct event_key *key __maybe_unused)
+{
+	return evsel__name_is(sample->evsel, kvm_entry_trace(EM_AARCH64));
+}
+
 static const struct kvm_events_ops exit_events = {
 	.is_begin_event = event_begin,
 	.is_end_event	= event_end,
-- 
2.9.4

Re: [PATCH] perf kvm: Fix arm64 VM-exit duration accounting

[Leo Yan]

On Sat, Oct 31, 2026 at 08:01:23PM +0800, lirongqing wrote:
> From: Li RongQing <lirongqing@baidu.com>
> 
> Use kvm_exit as the start event and the following kvm_entry as the
> end event for arm64 VM-exit statistics. Keep decoding ret and esr_ec
> from the exit sample.
> 
> Before this change, arm64 measured guest runtime as VM-exit time.
> 
> Fixes: 1218838d68f5 ("perf kvm: Add kvm-stat for arm64")
> Signed-off-by: Li RongQing <lirongqing@baidu.com>

Thanks for the fix!

Reviewed-by: Leo Yan <leo.yan@arm.com>

Since arm64 requires the exit reason, we cannot directly use the common
exit_event_begin()/exit_event_end() callbacks as other archs do.

Re: [PATCH] perf kvm: Fix arm64 VM-exit duration accounting

[Arnaldo Carvalho de Melo]

On Wed, Nov 04, 2026 at 11:17:51AM +0000, Leo Yan wrote:
> On Sat, Oct 31, 2026 at 08:01:23PM +0800, lirongqing wrote:
> > From: Li RongQing <lirongqing@baidu.com>
> > 
> > Use kvm_exit as the start event and the following kvm_entry as the
> > end event for arm64 VM-exit statistics. Keep decoding ret and esr_ec
> > from the exit sample.
> > 
> > Before this change, arm64 measured guest runtime as VM-exit time.
> > 
> > Fixes: 1218838d68f5 ("perf kvm: Add kvm-stat for arm64")
> > Signed-off-by: Li RongQing <lirongqing@baidu.com>
> 
> Thanks for the fix!
> 
> Reviewed-by: Leo Yan <leo.yan@arm.com>
> 
> Since arm64 requires the exit reason, we cannot directly use the common
> exit_event_begin()/exit_event_end() callbacks as other archs do.

Thanks, applied for v7.4.

- Arnaldo