[kvm-unit-tests PATCH] x86/pmu: Verify all available GP counters in check_counters_many()

[Dapeng Mi]

The intent of check_counters_many() is to verify all available counters
can count correctly at the same time. So an alternative event should be
picked to verify the avaialbe GP counter instead of skiping the counter
if the initial event is not available.

Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
---
Please notice this patch is based on Sean's "x86: Add CPUID properties,
 clean up related code" v2 patchset (https://lore.kernel.org/all/20250610195415.115404-1-seanjc@xxxxxxxxxx/).

 x86/pmu.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/x86/pmu.c b/x86/pmu.c
index 3987311c..a6b0cfcc 100644
--- a/x86/pmu.c
+++ b/x86/pmu.c
@@ -457,18 +457,34 @@ static void check_fixed_counters(void)
 	}
 }
 
+static struct pmu_event *get_one_event(int idx)
+{
+	int i;
+
+	if (pmu_arch_event_is_available(idx))
+		return &gp_events[idx % gp_events_size];
+
+	for (i = 0; i < gp_events_size; i++) {
+		if (pmu_arch_event_is_available(i))
+			return &gp_events[i];
+	}
+
+	return NULL;
+}
+
 static void check_counters_many(void)
 {
+	struct pmu_event *evt;
 	pmu_counter_t cnt[48];
 	int i, n;
 
 	for (i = 0, n = 0; n < pmu.nr_gp_counters; i++) {
-		if (!pmu_arch_event_is_available(i))
+		evt = get_one_event(i);
+		if (!evt)
 			continue;
 
 		cnt[n].ctr = MSR_GP_COUNTERx(n);
-		cnt[n].config = EVNTSEL_OS | EVNTSEL_USR |
-			gp_events[i % gp_events_size].unit_sel;
+		cnt[n].config = EVNTSEL_OS | EVNTSEL_USR | evt->unit_sel;
 		n++;
 	}
 	for (i = 0; i < fixed_counters_num; i++) {
-- 
2.43.0