Re: [PATCH v4 4/6] KVM: selftests: Add test cases for unsupported PMU event filter input values

Isaku Yamahata isaku.yamahata@gmail.com 于2023年7月19日周三 09:17写道：

On Mon, Jul 17, 2023 at 02:23:41PM +0800, Jinrong Liang ljr.kernel@gmail.com wrote:

...

From: Jinrong Liang cloudliang@tencent.com

Add test cases to verify the handling of unsupported input values for the PMU event filter. The tests cover unsupported "action" values, unsupported "flags" values, and unsupported "nevents" values. All these cases should return an error, as they are currently not supported by the filter. Furthermore, the tests also cover the scenario where setting non-existent fixed counters in the fixed bitmap does not fail.

Signed-off-by: Jinrong Liang cloudliang@tencent.com

.../kvm/x86_64/pmu_event_filter_test.c | 26 +++++++++++++++++++ 1 file changed, 26 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c index ffcbbf25b29b..63f85f583ef8 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c @@ -32,6 +32,10 @@ #define MAX_FILTER_EVENTS 300 #define MAX_TEST_EVENTS 10

+#define PMU_EVENT_FILTER_INVALID_ACTION (KVM_PMU_EVENT_DENY + 1) +#define PMU_EVENT_FILTER_INVALID_FLAGS (KVM_PMU_EVENT_FLAG_MASKED_EVENTS + 1)

flag is a bit mask. Not number. So +1 sounds weird. As KVM_PMU_EVENT_FLAGS_VALID_MASK = 1, this happens to get wanted result, though.

We need an invalid flags, KVM_PMU_EVENT_FLAGS_VALID_MASK is actually equal to KVM_PMU_EVENT_FLAG_MASKED_EVENTS.

In kvm.h:

#define KVM_PMU_EVENT_FLAG_MASKED_EVENTS BIT(0) #define KVM_PMU_EVENT_FLAGS_VALID_MASK (KVM_PMU_EVENT_FLAG_MASKED_EVENTS)

How about this modification:

#define PMU_EVENT_FILTER_INVALID_FLAGS (KVM_PMU_EVENT_FLAGS_VALID_MASK << 1)

...

+#define PMU_EVENT_FILTER_INVALID_NEVENTS (MAX_FILTER_EVENTS + 1)

/*

• This is how the event selector and unit mask are stored in an AMD
• core performance event-select register. Intel's format is similar,

@@ -757,6 +761,8 @@ static int set_pmu_single_event_filter(struct kvm_vcpu *vcpu, uint64_t event,

static void test_filter_ioctl(struct kvm_vcpu *vcpu) {

• uint8_t nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
  

• struct __kvm_pmu_event_filter f;
  uint64_t e = ~0ul;
  int r;
  
  

@@ -777,6 +783,26 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu) KVM_PMU_EVENT_FLAG_MASKED_EVENTS, KVM_PMU_EVENT_ALLOW); TEST_ASSERT(r == 0, "Valid PMU Event Filter is failing");

• f = base_event_filter;
  

• f.action = PMU_EVENT_FILTER_INVALID_ACTION;
  

• r = do_vcpu_set_pmu_event_filter(vcpu, &f);
  

• TEST_ASSERT(r, "Set invalid action is expected to fail");
  

• f = base_event_filter;
  

• f.flags = PMU_EVENT_FILTER_INVALID_FLAGS;
  

• r = do_vcpu_set_pmu_event_filter(vcpu, &f);
  

• TEST_ASSERT(r, "Set invalid flags is expected to fail");
  

• f = base_event_filter;
  

• f.nevents = PMU_EVENT_FILTER_INVALID_NEVENTS;
  

• r = do_vcpu_set_pmu_event_filter(vcpu, &f);
  

• TEST_ASSERT(r, "Exceeding the max number of filter events should fail");
  

• f = base_event_filter;
  

• f.fixed_counter_bitmap = ~GENMASK_ULL(nr_fixed_counters, 0);
  

• r = do_vcpu_set_pmu_event_filter(vcpu, &f);
  

• TEST_ASSERT(!r, "Masking non-existent fixed counters should be allowed");
  

}

int main(int argc, char *argv[])

2.39.3

-- Isaku Yamahata isaku.yamahata@gmail.com