Re: [Xen-devel] [PATCH 3/8] x86/AMD: Read VPMU MSRs from context when it is not loaded into HW

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

On Tue, Apr 16, 2013 at 12:12:16PM -0500, Jacob Shin wrote:
> On Tue, Apr 16, 2013 at 11:41:51AM -0400, Konrad Rzeszutek Wilk wrote:
> > On Thu, Apr 11, 2013 at 02:34:47PM -0400, Boris Ostrovsky wrote:
> > > On 04/11/2013 02:26 PM, Suravee Suthikulpanit wrote:
> > > >Boris,
> > > >
> > > >I tried booting the guest HVM after the patch, I still see PERF
> > > >only working in Software mode only.  I'll look more into this.
> > > 
> > > You may need to declare proper CPUID bits in the config file. On
> > > fam15h I have
> > > 
> > > cpuid=['0x80000001:ecx=00000001101000011000101111110011']
> > 
> > Would it be possible to write somewhere this magic incantention?
> > 
> > Perhaps in the xl.cfg.pod.5 ?
> > 
> > (This of course being a different patch).
> > 
> 
> Well, maybe we should turn it on by default?
> 
> http://lists.xen.org/archives/html/xen-devel/2013-04/msg01028.html:
> 
> 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) |
> 
> Or maybe not since vpmu is not on by default .. ?

I would say not yet. As the vpmu=1 (at least on Intel) has some issues.
Until that is fixed and vpmu=1 is by default lets leave it as so.

> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel