Re: [Xen-devel] [PATCH v10 11/20] x86/VPMU: Interface for setting PMU mode and flags

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Boris Ostrovsky [mailto:boris.ostrovsky@xxxxxxxxxx]
> Sent: Thursday, September 18, 2014 2:51 PM
> 
> > and how do you ensure
> > vpmu won't become dirty again if the target vcpu switches out, and then
> switches
> > back again to use vpmu, but before your whole hypercall completes? Here
> some
> > way is required to really stop vpmu on the target vcpu imho, but I may be
> wrong
> > on understanding the whole background here... :-)
> 
> I change vpmu_mode *before* calling this sync routine so even if remote
> VCPU comes on again it won't load that VCPU's VPMU. That's because the
> only time I do this sync is when I:
> * Turn VPMU mode off. In which case no VPMU will ever get loaded
> * Switch to XENPMU_MODE_ALL mode (in v11 version) in which case the only
> time VPMU will get loaded is if it's dom0's VPMU. Which is fine.

thanks it answers my question.

> >> diff --git a/xen/arch/x86/x86_64/compat/entry.S
> >> b/xen/arch/x86/x86_64/compat/entry.S
> >> index ac594c9..8587c46 100644
> >> --- a/xen/arch/x86/x86_64/compat/entry.S
> >> +++ b/xen/arch/x86/x86_64/compat/entry.S
> >> @@ -417,6 +417,8 @@ ENTRY(compat_hypercall_table)
> >>           .quad do_domctl
> >>           .quad compat_kexec_op
> >>           .quad do_tmem_op
> >> +        .quad do_ni_hypercall           /* reserved for XenClient */
> > why XenClient here?
> 
> See include/public/xen.h, hypercall 39.
> 

sorry but why it is included in this VPMU patch set?

Thanks
Kevin

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