Re: [Xen-devel] [PATCH V2] Add CPUID bit mask for Performance Counter Extension

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Tue, Mar 05, 2013 at 05:01:26PM -0600, suravee.suthikulpanit@xxxxxxx wrote:
> Adding CPUID bit mask for Performance Counter Extension. The extended 
> counter MSRs are already virtualized.  This bit mask allows the 
> initialization 
> code to properly detect the feature and enable the use of counters.

Just to be clear, to make use of this, the guest config has to have

cpuid="perfctr_core"

Is this something that is the same for Intel hardware? Meaning is the
code path in xl the same for enabling performance counters on Intel?

> 
> Signed-off-by: Jacob Shin <Jacob.Shin@xxxxxxx>
> Submitted-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> ---
> Changelog:
> V2:
>     * Add commit log message
> 
>  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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> http://lists.xen.org/xen-devel
> 

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