diff mbox series

[v3,3/3] x86: Check platform vPMU capabilities before run lbr tests

Message ID 20220624090828.62191-4-weijiang.yang@intel.com (mailing list archive)
State New, archived
Headers show
Series Fix up test failures due to recent KVM changes | expand

Commit Message

Yang, Weijiang June 24, 2022, 9:08 a.m. UTC
Use new helper to check whether pmu is available and Perfmon/Debug
capbilities are supported before read MSR_IA32_PERF_CAPABILITIES to
avoid test failure. The issue can be captured when enable_pmu=0.

Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
 lib/x86/processor.h |  2 +-
 x86/pmu_lbr.c       | 32 +++++++++++++-------------------
 2 files changed, 14 insertions(+), 20 deletions(-)

Comments

Sean Christopherson June 24, 2022, 10:23 p.m. UTC | #1
On Fri, Jun 24, 2022, Yang Weijiang wrote:
> Use new helper to check whether pmu is available and Perfmon/Debug
> capbilities are supported before read MSR_IA32_PERF_CAPABILITIES to
> avoid test failure. The issue can be captured when enable_pmu=0.
> 
> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> ---
>  lib/x86/processor.h |  2 +-
>  x86/pmu_lbr.c       | 32 +++++++++++++-------------------
>  2 files changed, 14 insertions(+), 20 deletions(-)
> 
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index 70b9193..bb917b0 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -193,7 +193,7 @@ static inline bool is_intel(void)
>  #define X86_FEATURE_PAUSEFILTER     (CPUID(0x8000000A, 0, EDX, 10))
>  #define X86_FEATURE_PFTHRESHOLD     (CPUID(0x8000000A, 0, EDX, 12))
>  #define	X86_FEATURE_VGIF		(CPUID(0x8000000A, 0, EDX, 16))
> -
> +#define	X86_FEATURE_PDCM		(CPUID(0x1, 0, ECX, 15))

Please try to think critically about the code you're writing.  All of the existing
X86_FEATURE_* definitions are organized by leaf, sub-leaf, register _and_ bit
position.  And now there's X86_FEATURE_PDCM...
Yang, Weijiang June 25, 2022, 6:38 a.m. UTC | #2
On 6/25/2022 6:23 AM, Sean Christopherson wrote:
> On Fri, Jun 24, 2022, Yang Weijiang wrote:
>> Use new helper to check whether pmu is available and Perfmon/Debug
>> capbilities are supported before read MSR_IA32_PERF_CAPABILITIES to
>> avoid test failure. The issue can be captured when enable_pmu=0.
>>
>> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
>> ---
>>   lib/x86/processor.h |  2 +-
>>   x86/pmu_lbr.c       | 32 +++++++++++++-------------------
>>   2 files changed, 14 insertions(+), 20 deletions(-)
>>
>> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
>> index 70b9193..bb917b0 100644
>> --- a/lib/x86/processor.h
>> +++ b/lib/x86/processor.h
>> @@ -193,7 +193,7 @@ static inline bool is_intel(void)
>>   #define X86_FEATURE_PAUSEFILTER     (CPUID(0x8000000A, 0, EDX, 10))
>>   #define X86_FEATURE_PFTHRESHOLD     (CPUID(0x8000000A, 0, EDX, 12))
>>   #define	X86_FEATURE_VGIF		(CPUID(0x8000000A, 0, EDX, 16))
>> -
>> +#define	X86_FEATURE_PDCM		(CPUID(0x1, 0, ECX, 15))
> Please try to think critically about the code you're writing.  All of the existing
> X86_FEATURE_* definitions are organized by leaf, sub-leaf, register _and_ bit
> position.  And now there's X86_FEATURE_PDCM...
My fault, will put it at the right place. thanks!
diff mbox series

Patch

diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index 70b9193..bb917b0 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -193,7 +193,7 @@  static inline bool is_intel(void)
 #define X86_FEATURE_PAUSEFILTER     (CPUID(0x8000000A, 0, EDX, 10))
 #define X86_FEATURE_PFTHRESHOLD     (CPUID(0x8000000A, 0, EDX, 12))
 #define	X86_FEATURE_VGIF		(CPUID(0x8000000A, 0, EDX, 16))
-
+#define	X86_FEATURE_PDCM		(CPUID(0x1, 0, ECX, 15))
 
 static inline bool this_cpu_has(u64 feature)
 {
diff --git a/x86/pmu_lbr.c b/x86/pmu_lbr.c
index 688634d..497df1e 100644
--- a/x86/pmu_lbr.c
+++ b/x86/pmu_lbr.c
@@ -15,6 +15,7 @@ 
 #define MSR_LBR_SELECT		0x000001c8
 
 volatile int count;
+u32 lbr_from, lbr_to;
 
 static noinline int compute_flag(int i)
 {
@@ -38,18 +39,6 @@  static noinline int lbr_test(void)
 	return 0;
 }
 
-union cpuid10_eax {
-	struct {
-		unsigned int version_id:8;
-		unsigned int num_counters:8;
-		unsigned int bit_width:8;
-		unsigned int mask_length:8;
-	} split;
-	unsigned int full;
-} eax;
-
-u32 lbr_from, lbr_to;
-
 static void init_lbr(void *index)
 {
 	wrmsr(lbr_from + *(int *) index, 0);
@@ -63,7 +52,7 @@  static bool test_init_lbr_from_exception(u64 index)
 
 int main(int ac, char **av)
 {
-	struct cpuid id = cpuid(10);
+	u8 version = pmu_version();
 	u64 perf_cap;
 	int max, i;
 
@@ -74,19 +63,24 @@  int main(int ac, char **av)
 		return 0;
 	}
 
-	perf_cap = rdmsr(MSR_IA32_PERF_CAPABILITIES);
-	eax.full = id.a;
-
-	if (!eax.split.version_id) {
+	if (!version) {
 		printf("No pmu is detected!\n");
 		return report_summary();
 	}
+
+	if (!this_cpu_has(X86_FEATURE_PDCM)) {
+		printf("Perfmon/Debug Capabilities MSR isn't supported\n");
+		return report_summary();
+	}
+
+	perf_cap = rdmsr(MSR_IA32_PERF_CAPABILITIES);
+
 	if (!(perf_cap & PMU_CAP_LBR_FMT)) {
-		printf("No LBR is detected!\n");
+		printf("(Architectural) LBR is not supported.\n");
 		return report_summary();
 	}
 
-	printf("PMU version:		 %d\n", eax.split.version_id);
+	printf("PMU version:		 %d\n", version);
 	printf("LBR version:		 %ld\n", perf_cap & PMU_CAP_LBR_FMT);
 
 	/* Look for LBR from and to MSRs */