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

[Jacob Shin <jacob.shin@xxxxxxx>]

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 .. ?


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