Re: [PATCH] Add CPUID bit mask for Performance Counter Extension

Suravee Suthikulanit
Tue, 05 Mar 2013 22:49:34 -0000

On 3/4/2013 4:07 AM, Jan Beulich wrote:
>>>> On 01.03.13 at 21:40, <suravee.suthikulpanit@amd.com>
wrote:
>> From: Jacob Shin <jacob.shin@amd.com>
> So are you saying that this will work for guests without _any_
> respective virtualization code in the hypervisor?
Yes. The MSRs are already virtualized.  This patch is just adding the
mask in the CPUID to allow feature detection in the initialization code.

> If so, it would be
> nice if there was text in the (currently empty) patch description
> making this explicit.
Sorry.  I am resending the patch with the commit log.

Suravee

>
> Jan
>
>> Signed-off-by: Jacob Shin <Jacob.Shin@amd.com>
>> Submitted-by: Suravee Suthikulpanit
<suravee.suthikulpanit@amd.com>
>> ---
>>   tools/libxc/xc_cpufeature.h |    1 +
>>   tools/libxc/xc_cpuid_x86.c  |    1 +
>>   tools/libxl/libxl_cpuid.c   |    1 +
>>   3 files changed, 3 insertions(+)
>>
>> diff --git a/tools/libxc/xc_cpufeature.h b/tools/libxc/xc_cpufeature.h
>> index c464e3a..c804af3 100644
>> --- a/tools/libxc/xc_cpufeature.h
>> +++ b/tools/libxc/xc_cpufeature.h
>> @@ -125,6 +125,7 @@
>>   #define X86_FEATURE_NODEID_MSR  19 /* NodeId MSR */
>>   #define X86_FEATURE_TBM         21 /* trailing bit manipulations */
>>   #define X86_FEATURE_TOPOEXT     22 /* topology extensions CPUID leafs
*/
>> +#define X86_FEATURE_PERFCTR_CORE 23 /* core performance counter
extensions
>> */
>>
>>   /* Intel-defined CPU features, CPUID level 0x00000007:0 (ebx) */
>>   #define X86_FEATURE_FSGSBASE     0 /* {RD,WR}{FS,GS}BASE instructions
*/
>> diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
>> index 17efc0f..c269468 100644
>> --- a/tools/libxc/xc_cpuid_x86.c
>> +++ b/tools/libxc/xc_cpuid_x86.c
>> @@ -112,6 +112,7 @@ static void amd_xc_cpuid_policy(
>>                       bitmaskof(X86_FEATURE_XOP) |
>>                       bitmaskof(X86_FEATURE_FMA4) |
>>                       bitmaskof(X86_FEATURE_TBM) |
>> +                    bitmaskof(X86_FEATURE_PERFCTR_CORE) |
>>                       bitmaskof(X86_FEATURE_LWP));
>>           regs[3] &= (0x0183f3ff | /* features shared with
0x00000001:EDX */
>>                       (is_pae ? bitmaskof(X86_FEATURE_NX) : 0) |
>> diff --git a/tools/libxl/libxl_cpuid.c b/tools/libxl/libxl_cpuid.c
>> index d17fdd6..f3f1265 100644
>> --- a/tools/libxl/libxl_cpuid.c
>> +++ b/tools/libxl/libxl_cpuid.c
>> @@ -147,6 +147,7 @@ int
libxl_cpuid_parse_config(libxl_cpuid_policy_list
>> *cpuid, const char* str)
>>           {"vme",          0x00000001, NA, CPUID_REG_EDX,  1,
1},
>>           {"fpu",          0x00000001, NA, CPUID_REG_EDX,  0,
1},
>>           {"topoext",      0x80000001, NA, CPUID_REG_ECX, 22,
1},
>> +        {"perfctr_core", 0x80000001, NA, CPUID_REG_ECX, 23,
1},
>>           {"tbm",          0x80000001, NA, CPUID_REG_ECX, 21,
1},
>>           {"nodeid",       0x80000001, NA, CPUID_REG_ECX, 19,
1},
>>           {"fma4",         0x80000001, NA, CPUID_REG_ECX, 16,
1},
>> --
>> 1.7.10.4
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