[PATCH kvm-unit-tests v2] pmu: fixes for Sandy Bridge hosts

[PATCH kvm-unit-tests v2] pmu: fixes for Sandy Bridge hosts

[Paolo Bonzini]

This patch includes two fixes for SB:

* the 3rd fixed counter ("ref cpu cycles") can sometimes report
  less than the number of iterations

* there is an 8th counter which causes out of bounds accesses
  to gp_event or check_counters_many's cnt array

There is still a bug in KVM, because the "pmu all counters-0"
test fails.  (It passes if you use any 6 of the 8 gp counters,
fails if you use 7 or 8).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 x86/pmu.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/x86/pmu.c b/x86/pmu.c
index 2c46f31..dca753a 100644
--- a/x86/pmu.c
+++ b/x86/pmu.c
@@ -88,9 +88,10 @@ struct pmu_event {
 }, fixed_events[] = {
 	{"fixed 1", MSR_CORE_PERF_FIXED_CTR0, 10*N, 10.2*N},
 	{"fixed 2", MSR_CORE_PERF_FIXED_CTR0 + 1, 1*N, 30*N},
-	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 1*N, 30*N}
+	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 0.1*N, 30*N}
 };
 
+static int num_counters;
 static int tests, failures;
 
 char *buf;
@@ -237,7 +238,7 @@ static void check_gp_counter(struct pmu_event *evt)
 	};
 	int i;
 
-	for (i = 0; i < eax.split.num_counters; i++, cnt.ctr++) {
+	for (i = 0; i < num_counters; i++, cnt.ctr++) {
 		cnt.count = 0;
 		measure(&cnt, 1);
 		report(evt->name, i, verify_event(cnt.count, evt));
@@ -276,7 +277,7 @@ static void check_counters_many(void)
 	pmu_counter_t cnt[10];
 	int i, n;
 
-	for (i = 0, n = 0; n < eax.split.num_counters; i++) {
+	for (i = 0, n = 0; n < num_counters; i++) {
 		if (ebx.full & (1 << i))
 			continue;
 
@@ -316,10 +317,10 @@ static void check_counter_overflow(void)
 	/* clear status before test */
 	wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, rdmsr(MSR_CORE_PERF_GLOBAL_STATUS));
 
-	for (i = 0; i < eax.split.num_counters + 1; i++, cnt.ctr++) {
+	for (i = 0; i < num_counters + 1; i++, cnt.ctr++) {
 		uint64_t status;
 		int idx;
-		if (i == eax.split.num_counters)
+		if (i == num_counters)
 			cnt.ctr = fixed_events[0].unit_sel;
 		if (i % 2)
 			cnt.config |= EVNTSEL_INT;
@@ -355,7 +356,7 @@ static void check_rdpmc(void)
 	uint64_t val = 0x1f3456789ull;
 	int i;
 
-	for (i = 0; i < eax.split.num_counters; i++) {
+	for (i = 0; i < num_counters; i++) {
 		uint64_t x = (val & 0xffffffff) |
 			((1ull << (eax.split.bit_width - 32)) - 1) << 32;
 		wrmsr(MSR_IA32_PERFCTR0 + i, val);
@@ -395,6 +396,10 @@ int main(int ac, char **av)
 	printf("Fixed counters:      %d\n", edx.split.num_counters_fixed);
 	printf("Fixed counter width: %d\n", edx.split.bit_width_fixed);
 
+	num_counters = eax.split.num_counters;
+	if (num_counters > ARRAY_SIZE(gp_events))
+		num_counters = ARRAY_SIZE(gp_events);
+
 	apic_write(APIC_LVTPC, PC_VECTOR);
 
 	check_gp_counters();
-- 
1.8.2.1

Re: [PATCH kvm-unit-tests v2] pmu: fixes for Sandy Bridge hosts

[Gleb Natapov]

On Thu, May 30, 2013 at 07:47:18PM +0200, Paolo Bonzini wrote:
> This patch includes two fixes for SB:
> 
> * the 3rd fixed counter ("ref cpu cycles") can sometimes report
>   less than the number of iterations
> 
> * there is an 8th counter which causes out of bounds accesses
>   to gp_event or check_counters_many's cnt array
> 
> There is still a bug in KVM, because the "pmu all counters-0"
> test fails.  (It passes if you use any 6 of the 8 gp counters,
> fails if you use 7 or 8).
> 
Changelog?

> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  x86/pmu.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/x86/pmu.c b/x86/pmu.c
> index 2c46f31..dca753a 100644
> --- a/x86/pmu.c
> +++ b/x86/pmu.c
> @@ -88,9 +88,10 @@ struct pmu_event {
>  }, fixed_events[] = {
>  	{"fixed 1", MSR_CORE_PERF_FIXED_CTR0, 10*N, 10.2*N},
>  	{"fixed 2", MSR_CORE_PERF_FIXED_CTR0 + 1, 1*N, 30*N},
> -	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 1*N, 30*N}
> +	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 0.1*N, 30*N}
>  };
>  
> +static int num_counters;
>  static int tests, failures;
>  
>  char *buf;
> @@ -237,7 +238,7 @@ static void check_gp_counter(struct pmu_event *evt)
>  	};
>  	int i;
>  
> -	for (i = 0; i < eax.split.num_counters; i++, cnt.ctr++) {
> +	for (i = 0; i < num_counters; i++, cnt.ctr++) {
>  		cnt.count = 0;
>  		measure(&cnt, 1);
>  		report(evt->name, i, verify_event(cnt.count, evt));
> @@ -276,7 +277,7 @@ static void check_counters_many(void)
>  	pmu_counter_t cnt[10];
>  	int i, n;
>  
> -	for (i = 0, n = 0; n < eax.split.num_counters; i++) {
> +	for (i = 0, n = 0; n < num_counters; i++) {
>  		if (ebx.full & (1 << i))
>  			continue;
>  
> @@ -316,10 +317,10 @@ static void check_counter_overflow(void)
>  	/* clear status before test */
>  	wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, rdmsr(MSR_CORE_PERF_GLOBAL_STATUS));
>  
> -	for (i = 0; i < eax.split.num_counters + 1; i++, cnt.ctr++) {
> +	for (i = 0; i < num_counters + 1; i++, cnt.ctr++) {
>  		uint64_t status;
>  		int idx;
> -		if (i == eax.split.num_counters)
> +		if (i == num_counters)
>  			cnt.ctr = fixed_events[0].unit_sel;
>  		if (i % 2)
>  			cnt.config |= EVNTSEL_INT;
> @@ -355,7 +356,7 @@ static void check_rdpmc(void)
>  	uint64_t val = 0x1f3456789ull;
>  	int i;
>  
> -	for (i = 0; i < eax.split.num_counters; i++) {
> +	for (i = 0; i < num_counters; i++) {
>  		uint64_t x = (val & 0xffffffff) |
>  			((1ull << (eax.split.bit_width - 32)) - 1) << 32;
>  		wrmsr(MSR_IA32_PERFCTR0 + i, val);
> @@ -395,6 +396,10 @@ int main(int ac, char **av)
>  	printf("Fixed counters:      %d\n", edx.split.num_counters_fixed);
>  	printf("Fixed counter width: %d\n", edx.split.bit_width_fixed);
>  
> +	num_counters = eax.split.num_counters;
> +	if (num_counters > ARRAY_SIZE(gp_events))
> +		num_counters = ARRAY_SIZE(gp_events);
> +
>  	apic_write(APIC_LVTPC, PC_VECTOR);
>  
>  	check_gp_counters();
> -- 
> 1.8.2.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
			Gleb.

Re: [PATCH kvm-unit-tests v2] pmu: fixes for Sandy Bridge hosts

[Paolo Bonzini]

Il 02/06/2013 17:33, Gleb Natapov ha scritto:
> On Thu, May 30, 2013 at 07:47:18PM +0200, Paolo Bonzini wrote:
>> This patch includes two fixes for SB:
>>
>> * the 3rd fixed counter ("ref cpu cycles") can sometimes report
>>   less than the number of iterations
>>
>> * there is an 8th counter which causes out of bounds accesses
>>   to gp_event or check_counters_many's cnt array
>>
>> There is still a bug in KVM, because the "pmu all counters-0"
>> test fails.  (It passes if you use any 6 of the 8 gp counters,
>> fails if you use 7 or 8).
>>
> Changelog?

Changelog is simply that the patch applies. :(

v1 was hand-edited and I did not regenerate it after testing the edit:

-@@ -395,6 +396,14 @@ int main(int ac, char **av)
+@@ -395,6 +396,10 @@ int main(int ac, char **av)

Paolo

>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>  x86/pmu.c | 21 +++++++++++++++------
>>  1 file changed, 15 insertions(+), 6 deletions(-)
>>
>> diff --git a/x86/pmu.c b/x86/pmu.c
>> index 2c46f31..dca753a 100644
>> --- a/x86/pmu.c
>> +++ b/x86/pmu.c
>> @@ -88,9 +88,10 @@ struct pmu_event {
>>  }, fixed_events[] = {
>>  	{"fixed 1", MSR_CORE_PERF_FIXED_CTR0, 10*N, 10.2*N},
>>  	{"fixed 2", MSR_CORE_PERF_FIXED_CTR0 + 1, 1*N, 30*N},
>> -	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 1*N, 30*N}
>> +	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 0.1*N, 30*N}
>>  };
>>  
>> +static int num_counters;
>>  static int tests, failures;
>>  
>>  char *buf;
>> @@ -237,7 +238,7 @@ static void check_gp_counter(struct pmu_event *evt)
>>  	};
>>  	int i;
>>  
>> -	for (i = 0; i < eax.split.num_counters; i++, cnt.ctr++) {
>> +	for (i = 0; i < num_counters; i++, cnt.ctr++) {
>>  		cnt.count = 0;
>>  		measure(&cnt, 1);
>>  		report(evt->name, i, verify_event(cnt.count, evt));
>> @@ -276,7 +277,7 @@ static void check_counters_many(void)
>>  	pmu_counter_t cnt[10];
>>  	int i, n;
>>  
>> -	for (i = 0, n = 0; n < eax.split.num_counters; i++) {
>> +	for (i = 0, n = 0; n < num_counters; i++) {
>>  		if (ebx.full & (1 << i))
>>  			continue;
>>  
>> @@ -316,10 +317,10 @@ static void check_counter_overflow(void)
>>  	/* clear status before test */
>>  	wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, rdmsr(MSR_CORE_PERF_GLOBAL_STATUS));
>>  
>> -	for (i = 0; i < eax.split.num_counters + 1; i++, cnt.ctr++) {
>> +	for (i = 0; i < num_counters + 1; i++, cnt.ctr++) {
>>  		uint64_t status;
>>  		int idx;
>> -		if (i == eax.split.num_counters)
>> +		if (i == num_counters)
>>  			cnt.ctr = fixed_events[0].unit_sel;
>>  		if (i % 2)
>>  			cnt.config |= EVNTSEL_INT;
>> @@ -355,7 +356,7 @@ static void check_rdpmc(void)
>>  	uint64_t val = 0x1f3456789ull;
>>  	int i;
>>  
>> -	for (i = 0; i < eax.split.num_counters; i++) {
>> +	for (i = 0; i < num_counters; i++) {
>>  		uint64_t x = (val & 0xffffffff) |
>>  			((1ull << (eax.split.bit_width - 32)) - 1) << 32;
>>  		wrmsr(MSR_IA32_PERFCTR0 + i, val);
>> @@ -395,6 +396,10 @@ int main(int ac, char **av)
>>  	printf("Fixed counters:      %d\n", edx.split.num_counters_fixed);
>>  	printf("Fixed counter width: %d\n", edx.split.bit_width_fixed);
>>  
>> +	num_counters = eax.split.num_counters;
>> +	if (num_counters > ARRAY_SIZE(gp_events))
>> +		num_counters = ARRAY_SIZE(gp_events);
>> +
>>  	apic_write(APIC_LVTPC, PC_VECTOR);
>>  
>>  	check_gp_counters();
>> -- 
>> 1.8.2.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> --
> 			Gleb.
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH kvm-unit-tests v2] pmu: fixes for Sandy Bridge hosts

[Gleb Natapov]

On Mon, Jun 03, 2013 at 08:35:21AM +0200, Paolo Bonzini wrote:
> Il 02/06/2013 17:33, Gleb Natapov ha scritto:
> > On Thu, May 30, 2013 at 07:47:18PM +0200, Paolo Bonzini wrote:
> >> This patch includes two fixes for SB:
> >>
> >> * the 3rd fixed counter ("ref cpu cycles") can sometimes report
> >>   less than the number of iterations
> >>
> >> * there is an 8th counter which causes out of bounds accesses
> >>   to gp_event or check_counters_many's cnt array
> >>
> >> There is still a bug in KVM, because the "pmu all counters-0"
> >> test fails.  (It passes if you use any 6 of the 8 gp counters,
> >> fails if you use 7 or 8).
> >>
> > Changelog?
> 
> Changelog is simply that the patch applies. :(
> 
Just say so, I tried to see how they are different and failed.

> v1 was hand-edited and I did not regenerate it after testing the edit:
> 
> -@@ -395,6 +396,14 @@ int main(int ac, char **av)
> +@@ -395,6 +396,10 @@ int main(int ac, char **av)
> 
Yeah, hard to spot :)

> Paolo
> 
> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> >> ---
> >>  x86/pmu.c | 21 +++++++++++++++------
> >>  1 file changed, 15 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/x86/pmu.c b/x86/pmu.c
> >> index 2c46f31..dca753a 100644
> >> --- a/x86/pmu.c
> >> +++ b/x86/pmu.c
> >> @@ -88,9 +88,10 @@ struct pmu_event {
> >>  }, fixed_events[] = {
> >>  	{"fixed 1", MSR_CORE_PERF_FIXED_CTR0, 10*N, 10.2*N},
> >>  	{"fixed 2", MSR_CORE_PERF_FIXED_CTR0 + 1, 1*N, 30*N},
> >> -	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 1*N, 30*N}
> >> +	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 0.1*N, 30*N}
> >>  };
> >>  
> >> +static int num_counters;
> >>  static int tests, failures;
> >>  
> >>  char *buf;
> >> @@ -237,7 +238,7 @@ static void check_gp_counter(struct pmu_event *evt)
> >>  	};
> >>  	int i;
> >>  
> >> -	for (i = 0; i < eax.split.num_counters; i++, cnt.ctr++) {
> >> +	for (i = 0; i < num_counters; i++, cnt.ctr++) {
> >>  		cnt.count = 0;
> >>  		measure(&cnt, 1);
> >>  		report(evt->name, i, verify_event(cnt.count, evt));
> >> @@ -276,7 +277,7 @@ static void check_counters_many(void)
> >>  	pmu_counter_t cnt[10];
> >>  	int i, n;
> >>  
> >> -	for (i = 0, n = 0; n < eax.split.num_counters; i++) {
> >> +	for (i = 0, n = 0; n < num_counters; i++) {
> >>  		if (ebx.full & (1 << i))
> >>  			continue;
> >>  
> >> @@ -316,10 +317,10 @@ static void check_counter_overflow(void)
> >>  	/* clear status before test */
> >>  	wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, rdmsr(MSR_CORE_PERF_GLOBAL_STATUS));
> >>  
> >> -	for (i = 0; i < eax.split.num_counters + 1; i++, cnt.ctr++) {
> >> +	for (i = 0; i < num_counters + 1; i++, cnt.ctr++) {
> >>  		uint64_t status;
> >>  		int idx;
> >> -		if (i == eax.split.num_counters)
> >> +		if (i == num_counters)
> >>  			cnt.ctr = fixed_events[0].unit_sel;
> >>  		if (i % 2)
> >>  			cnt.config |= EVNTSEL_INT;
> >> @@ -355,7 +356,7 @@ static void check_rdpmc(void)
> >>  	uint64_t val = 0x1f3456789ull;
> >>  	int i;
> >>  
> >> -	for (i = 0; i < eax.split.num_counters; i++) {
> >> +	for (i = 0; i < num_counters; i++) {
> >>  		uint64_t x = (val & 0xffffffff) |
> >>  			((1ull << (eax.split.bit_width - 32)) - 1) << 32;
> >>  		wrmsr(MSR_IA32_PERFCTR0 + i, val);
> >> @@ -395,6 +396,10 @@ int main(int ac, char **av)
> >>  	printf("Fixed counters:      %d\n", edx.split.num_counters_fixed);
> >>  	printf("Fixed counter width: %d\n", edx.split.bit_width_fixed);
> >>  
> >> +	num_counters = eax.split.num_counters;
> >> +	if (num_counters > ARRAY_SIZE(gp_events))
> >> +		num_counters = ARRAY_SIZE(gp_events);
> >> +
> >>  	apic_write(APIC_LVTPC, PC_VECTOR);
> >>  
> >>  	check_gp_counters();
> >> -- 
> >> 1.8.2.1
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe kvm" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> > --
> > 			Gleb.
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 

--
			Gleb.

Re: [PATCH kvm-unit-tests v2] pmu: fixes for Sandy Bridge hosts

[Gleb Natapov]

On Thu, May 30, 2013 at 07:47:18PM +0200, Paolo Bonzini wrote:
> This patch includes two fixes for SB:
> 
> * the 3rd fixed counter ("ref cpu cycles") can sometimes report
>   less than the number of iterations
> 
> * there is an 8th counter which causes out of bounds accesses
>   to gp_event or check_counters_many's cnt array
> 
> There is still a bug in KVM, because the "pmu all counters-0"
> test fails.  (It passes if you use any 6 of the 8 gp counters,
> fails if you use 7 or 8).
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Applied, thanks.

> ---
>  x86/pmu.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/x86/pmu.c b/x86/pmu.c
> index 2c46f31..dca753a 100644
> --- a/x86/pmu.c
> +++ b/x86/pmu.c
> @@ -88,9 +88,10 @@ struct pmu_event {
>  }, fixed_events[] = {
>  	{"fixed 1", MSR_CORE_PERF_FIXED_CTR0, 10*N, 10.2*N},
>  	{"fixed 2", MSR_CORE_PERF_FIXED_CTR0 + 1, 1*N, 30*N},
> -	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 1*N, 30*N}
> +	{"fixed 3", MSR_CORE_PERF_FIXED_CTR0 + 2, 0.1*N, 30*N}
>  };
>  
> +static int num_counters;
>  static int tests, failures;
>  
>  char *buf;
> @@ -237,7 +238,7 @@ static void check_gp_counter(struct pmu_event *evt)
>  	};
>  	int i;
>  
> -	for (i = 0; i < eax.split.num_counters; i++, cnt.ctr++) {
> +	for (i = 0; i < num_counters; i++, cnt.ctr++) {
>  		cnt.count = 0;
>  		measure(&cnt, 1);
>  		report(evt->name, i, verify_event(cnt.count, evt));
> @@ -276,7 +277,7 @@ static void check_counters_many(void)
>  	pmu_counter_t cnt[10];
>  	int i, n;
>  
> -	for (i = 0, n = 0; n < eax.split.num_counters; i++) {
> +	for (i = 0, n = 0; n < num_counters; i++) {
>  		if (ebx.full & (1 << i))
>  			continue;
>  
> @@ -316,10 +317,10 @@ static void check_counter_overflow(void)
>  	/* clear status before test */
>  	wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, rdmsr(MSR_CORE_PERF_GLOBAL_STATUS));
>  
> -	for (i = 0; i < eax.split.num_counters + 1; i++, cnt.ctr++) {
> +	for (i = 0; i < num_counters + 1; i++, cnt.ctr++) {
>  		uint64_t status;
>  		int idx;
> -		if (i == eax.split.num_counters)
> +		if (i == num_counters)
>  			cnt.ctr = fixed_events[0].unit_sel;
>  		if (i % 2)
>  			cnt.config |= EVNTSEL_INT;
> @@ -355,7 +356,7 @@ static void check_rdpmc(void)
>  	uint64_t val = 0x1f3456789ull;
>  	int i;
>  
> -	for (i = 0; i < eax.split.num_counters; i++) {
> +	for (i = 0; i < num_counters; i++) {
>  		uint64_t x = (val & 0xffffffff) |
>  			((1ull << (eax.split.bit_width - 32)) - 1) << 32;
>  		wrmsr(MSR_IA32_PERFCTR0 + i, val);
> @@ -395,6 +396,10 @@ int main(int ac, char **av)
>  	printf("Fixed counters:      %d\n", edx.split.num_counters_fixed);
>  	printf("Fixed counter width: %d\n", edx.split.bit_width_fixed);
>  
> +	num_counters = eax.split.num_counters;
> +	if (num_counters > ARRAY_SIZE(gp_events))
> +		num_counters = ARRAY_SIZE(gp_events);
> +
>  	apic_write(APIC_LVTPC, PC_VECTOR);
>  
>  	check_gp_counters();
> -- 
> 1.8.2.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
			Gleb.