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

[Suravee Suthikulanit <suravee.suthikulpanit@xxxxxxx>]

On 3/4/2013 4:07 AM, Jan Beulich wrote:
> > > > On 01.03.13 at 21:40, <suravee.suthikulpanit@xxxxxxx> wrote:
> > From: Jacob Shin <jacob.shin@xxxxxxx>
> 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@xxxxxxx>
> > Submitted-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> > ---
> >   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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