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Date:   Tue, 18 Jul 2023 17:02:45 -0700
From:   Isaku Yamahata <isaku.yamahata@gmail.com>
To:     Jinrong Liang <ljr.kernel@gmail.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Jim Mattson <jmattson@google.com>,
        Shuah Khan <shuah@kernel.org>,
        Aaron Lewis <aaronlewis@google.com>,
        David Matlack <dmatlack@google.com>,
        Vishal Annapurve <vannapurve@google.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Like Xu <like.xu.linux@gmail.com>,
        Jinrong Liang <cloudliang@tencent.com>,
        linux-kselftest@vger.kernel.org, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, isaku.yamahata@gmail.com
Subject: Re: [PATCH v4 3/6] KVM: selftests: Introduce __kvm_pmu_event_filter
 to improved event filter settings
Message-ID: <20230719000245.GC25699@ls.amr.corp.intel.com>
References: <20230717062343.3743-1-cloudliang@tencent.com>
 <20230717062343.3743-4-cloudliang@tencent.com>
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On Mon, Jul 17, 2023 at 02:23:40PM +0800,
Jinrong Liang <ljr.kernel@gmail.com> wrote:

> From: Jinrong Liang <cloudliang@tencent.com>
> 
> Add custom "__kvm_pmu_event_filter" structure to improve pmu event
> filter settings. Simplifies event filter setup by organizing event
> filter parameters in a cleaner, more organized way.
> 
> Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
> ---
>  .../kvm/x86_64/pmu_event_filter_test.c        | 179 +++++++++---------
>  1 file changed, 87 insertions(+), 92 deletions(-)
> 
> 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 5ac05e64bec9..ffcbbf25b29b 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
> @@ -28,6 +28,10 @@
>  
>  #define NUM_BRANCHES 42
>  
> +/* Matches KVM_PMU_EVENT_FILTER_MAX_EVENTS in pmu.c */
> +#define MAX_FILTER_EVENTS		300
> +#define MAX_TEST_EVENTS		10
> +
>  /*
>   * This is how the event selector and unit mask are stored in an AMD
>   * core performance event-select register. Intel's format is similar,
> @@ -69,21 +73,33 @@
>  
>  #define INST_RETIRED EVENT(0xc0, 0)
>  
> +struct __kvm_pmu_event_filter {
> +	__u32 action;
> +	__u32 nevents;
> +	__u32 fixed_counter_bitmap;
> +	__u32 flags;
> +	__u32 pad[4];
> +	__u64 events[MAX_FILTER_EVENTS];
> +};
> +
>  /*
>   * This event list comprises Intel's eight architectural events plus
>   * AMD's "retired branch instructions" for Zen[123] (and possibly
>   * other AMD CPUs).
>   */
> -static const uint64_t event_list[] = {
> -	EVENT(0x3c, 0),
> -	INST_RETIRED,
> -	EVENT(0x3c, 1),
> -	EVENT(0x2e, 0x4f),
> -	EVENT(0x2e, 0x41),
> -	EVENT(0xc4, 0),
> -	EVENT(0xc5, 0),
> -	EVENT(0xa4, 1),
> -	AMD_ZEN_BR_RETIRED,
> +static const struct __kvm_pmu_event_filter base_event_filter = {
> +	.nevents = ARRAY_SIZE(base_event_filter.events),
> +	.events = {
> +		EVENT(0x3c, 0),
> +		INST_RETIRED,
> +		EVENT(0x3c, 1),
> +		EVENT(0x2e, 0x4f),
> +		EVENT(0x2e, 0x41),
> +		EVENT(0xc4, 0),
> +		EVENT(0xc5, 0),
> +		EVENT(0xa4, 1),
> +		AMD_ZEN_BR_RETIRED,
> +	},
>  };
>  
>  struct {
> @@ -225,47 +241,11 @@ static bool sanity_check_pmu(struct kvm_vcpu *vcpu)
>  	return !r;
>  }
>  
> -static struct kvm_pmu_event_filter *alloc_pmu_event_filter(uint32_t nevents)
> -{
> -	struct kvm_pmu_event_filter *f;
> -	int size = sizeof(*f) + nevents * sizeof(f->events[0]);
> -
> -	f = malloc(size);
> -	TEST_ASSERT(f, "Out of memory");
> -	memset(f, 0, size);
> -	f->nevents = nevents;
> -	return f;
> -}
> -
> -
> -static struct kvm_pmu_event_filter *
> -create_pmu_event_filter(const uint64_t event_list[], int nevents,
> -			uint32_t action, uint32_t flags)
> -{
> -	struct kvm_pmu_event_filter *f;
> -	int i;
> -
> -	f = alloc_pmu_event_filter(nevents);
> -	f->action = action;
> -	f->flags = flags;
> -	for (i = 0; i < nevents; i++)
> -		f->events[i] = event_list[i];
> -
> -	return f;
> -}
> -
> -static struct kvm_pmu_event_filter *event_filter(uint32_t action)
> -{
> -	return create_pmu_event_filter(event_list,
> -				       ARRAY_SIZE(event_list),
> -				       action, 0);
> -}
> -
>  /*
>   * Remove the first occurrence of 'event' (if any) from the filter's
>   * event list.
>   */
> -static void remove_event(struct kvm_pmu_event_filter *f, uint64_t event)
> +static void remove_event(struct __kvm_pmu_event_filter *f, uint64_t event)
>  {
>  	bool found = false;
>  	int i;
> @@ -313,66 +293,70 @@ static void test_without_filter(struct kvm_vcpu *vcpu)
>  }
>  
>  static void test_with_filter(struct kvm_vcpu *vcpu,
> -			     struct kvm_pmu_event_filter *f)
> +			     struct __kvm_pmu_event_filter *__f)
>  {
> +	struct kvm_pmu_event_filter *f = (void *)__f;
> +
>  	vm_ioctl(vcpu->vm, KVM_SET_PMU_EVENT_FILTER, f);
>  	run_vcpu_and_sync_pmc_results(vcpu);
>  }
>  
>  static void test_amd_deny_list(struct kvm_vcpu *vcpu)
>  {
> -	uint64_t event = EVENT(0x1C2, 0);
> -	struct kvm_pmu_event_filter *f;
> +	struct __kvm_pmu_event_filter f = base_event_filter;
>  
> -	f = create_pmu_event_filter(&event, 1, KVM_PMU_EVENT_DENY, 0);
> -	test_with_filter(vcpu, f);
> -	free(f);
> +	f.action = KVM_PMU_EVENT_DENY;
> +	f.nevents = 1;
> +	f.events[0] = EVENT(0x1C2, 0);
> +	test_with_filter(vcpu, &f);

This overwrite all members.  We can use designated initializer.
	struct __kvm_pmu_event_filter f = {
                .action = KVM_PMU_EVENT_DENY,
                .nevents = 1,
                .events = {
                        EVENT(0x1C2, 0),
                },
        };

Except this, looks good to me.
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>

Thanks,

>  
>  	ASSERT_PMC_COUNTING_INSTRUCTIONS();
>  }
>  
>  static void test_member_deny_list(struct kvm_vcpu *vcpu)
>  {
> -	struct kvm_pmu_event_filter *f = event_filter(KVM_PMU_EVENT_DENY);
> +	struct __kvm_pmu_event_filter f = base_event_filter;
>  
> -	test_with_filter(vcpu, f);
> -	free(f);
> +	f.action = KVM_PMU_EVENT_DENY;
> +	test_with_filter(vcpu, &f);
>  
>  	ASSERT_PMC_NOT_COUNTING_INSTRUCTIONS();
>  }
>  
>  static void test_member_allow_list(struct kvm_vcpu *vcpu)
>  {
> -	struct kvm_pmu_event_filter *f = event_filter(KVM_PMU_EVENT_ALLOW);
> +	struct __kvm_pmu_event_filter f = base_event_filter;
>  
> -	test_with_filter(vcpu, f);
> -	free(f);
> +	f.action = KVM_PMU_EVENT_ALLOW;
> +	test_with_filter(vcpu, &f);
>  
>  	ASSERT_PMC_COUNTING_INSTRUCTIONS();
>  }
>  
>  static void test_not_member_deny_list(struct kvm_vcpu *vcpu)
>  {
> -	struct kvm_pmu_event_filter *f = event_filter(KVM_PMU_EVENT_DENY);
> +	struct __kvm_pmu_event_filter f = base_event_filter;
> +
> +	f.action = KVM_PMU_EVENT_DENY;
>  
> -	remove_event(f, INST_RETIRED);
> -	remove_event(f, INTEL_BR_RETIRED);
> -	remove_event(f, AMD_ZEN_BR_RETIRED);
> -	test_with_filter(vcpu, f);
> -	free(f);
> +	remove_event(&f, INST_RETIRED);
> +	remove_event(&f, INTEL_BR_RETIRED);
> +	remove_event(&f, AMD_ZEN_BR_RETIRED);
> +	test_with_filter(vcpu, &f);
>  
>  	ASSERT_PMC_COUNTING_INSTRUCTIONS();
>  }
>  
>  static void test_not_member_allow_list(struct kvm_vcpu *vcpu)
>  {
> -	struct kvm_pmu_event_filter *f = event_filter(KVM_PMU_EVENT_ALLOW);
> +	struct __kvm_pmu_event_filter f = base_event_filter;
>  
> -	remove_event(f, INST_RETIRED);
> -	remove_event(f, INTEL_BR_RETIRED);
> -	remove_event(f, AMD_ZEN_BR_RETIRED);
> -	test_with_filter(vcpu, f);
> -	free(f);
> +	f.action = KVM_PMU_EVENT_ALLOW;
> +
> +	remove_event(&f, INST_RETIRED);
> +	remove_event(&f, INTEL_BR_RETIRED);
> +	remove_event(&f, AMD_ZEN_BR_RETIRED);
> +	test_with_filter(vcpu, &f);
>  
>  	ASSERT_PMC_NOT_COUNTING_INSTRUCTIONS();
>  }
> @@ -567,19 +551,16 @@ static void run_masked_events_test(struct kvm_vcpu *vcpu,
>  				   const uint64_t masked_events[],
>  				   const int nmasked_events)
>  {
> -	struct kvm_pmu_event_filter *f;
> +	struct __kvm_pmu_event_filter f = {
> +		.nevents = nmasked_events,
> +		.action = KVM_PMU_EVENT_ALLOW,
> +		.flags = KVM_PMU_EVENT_FLAG_MASKED_EVENTS,
> +	};
>  
> -	f = create_pmu_event_filter(masked_events, nmasked_events,
> -				    KVM_PMU_EVENT_ALLOW,
> -				    KVM_PMU_EVENT_FLAG_MASKED_EVENTS);
> -	test_with_filter(vcpu, f);
> -	free(f);
> +	memcpy(f.events, masked_events, sizeof(uint64_t) * nmasked_events);
> +	test_with_filter(vcpu, &f);
>  }
>  
> -/* Matches KVM_PMU_EVENT_FILTER_MAX_EVENTS in pmu.c */
> -#define MAX_FILTER_EVENTS	300
> -#define MAX_TEST_EVENTS		10
> -
>  #define ALLOW_LOADS		BIT(0)
>  #define ALLOW_STORES		BIT(1)
>  #define ALLOW_LOADS_STORES	BIT(2)
> @@ -751,17 +732,27 @@ static void test_masked_events(struct kvm_vcpu *vcpu)
>  	run_masked_events_tests(vcpu, events, nevents);
>  }
>  
> -static int run_filter_test(struct kvm_vcpu *vcpu, const uint64_t *events,
> -			   int nevents, uint32_t flags)
> +static int do_vcpu_set_pmu_event_filter(struct kvm_vcpu *vcpu,
> +					struct __kvm_pmu_event_filter *__f)
>  {
> -	struct kvm_pmu_event_filter *f;
> -	int r;
> +	struct kvm_pmu_event_filter *f = (void *)__f;
>  
> -	f = create_pmu_event_filter(events, nevents, KVM_PMU_EVENT_ALLOW, flags);
> -	r = __vm_ioctl(vcpu->vm, KVM_SET_PMU_EVENT_FILTER, f);
> -	free(f);
> +	return __vm_ioctl(vcpu->vm, KVM_SET_PMU_EVENT_FILTER, f);
> +}
> +
> +static int set_pmu_single_event_filter(struct kvm_vcpu *vcpu, uint64_t event,
> +				       uint32_t flags, uint32_t action)
> +{
> +	struct __kvm_pmu_event_filter f = {
> +		.nevents = 1,
> +		.flags = flags,
> +		.action = action,
> +		.events = {
> +			event,
> +		},
> +	};
>  
> -	return r;
> +	return do_vcpu_set_pmu_event_filter(vcpu, &f);
>  }
>  
>  static void test_filter_ioctl(struct kvm_vcpu *vcpu)
> @@ -773,14 +764,18 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu)
>  	 * Unfortunately having invalid bits set in event data is expected to
>  	 * pass when flags == 0 (bits other than eventsel+umask).
>  	 */
> -	r = run_filter_test(vcpu, &e, 1, 0);
> +	r = set_pmu_single_event_filter(vcpu, e, 0, KVM_PMU_EVENT_ALLOW);
>  	TEST_ASSERT(r == 0, "Valid PMU Event Filter is failing");
>  
> -	r = run_filter_test(vcpu, &e, 1, KVM_PMU_EVENT_FLAG_MASKED_EVENTS);
> +	r = set_pmu_single_event_filter(vcpu, e,
> +					KVM_PMU_EVENT_FLAG_MASKED_EVENTS,
> +					KVM_PMU_EVENT_ALLOW);
>  	TEST_ASSERT(r != 0, "Invalid PMU Event Filter is expected to fail");
>  
>  	e = KVM_PMU_ENCODE_MASKED_ENTRY(0xff, 0xff, 0xff, 0xf);
> -	r = run_filter_test(vcpu, &e, 1, KVM_PMU_EVENT_FLAG_MASKED_EVENTS);
> +	r = set_pmu_single_event_filter(vcpu, e,
> +					KVM_PMU_EVENT_FLAG_MASKED_EVENTS,
> +					KVM_PMU_EVENT_ALLOW);
>  	TEST_ASSERT(r == 0, "Valid PMU Event Filter is failing");
>  }
>  
> -- 
> 2.39.3
> 

-- 
Isaku Yamahata <isaku.yamahata@gmail.com>