RE: [PATCH V2 1/3] perf ignore LBR and offcore_rsp.

From: Liang, Kan
Date: Thu Jul 03 2014 - 00:27:00 EST




>
> On Wed, Jul 2, 2014 at 2:14 PM, <kan.liang@xxxxxxxxx> wrote:
> > From: Kan Liang <kan.liang@xxxxxxxxx>
> >
> > x86, perf: Protect LBR and offcore rsp against KVM lying
> >
> > With -cpu host, KVM reports LBR and offcore support, if the host has
> support.
> > When the guest perf driver tries to access LBR or offcore_rsp MSR, it
> > #GPs all MSR accesses,since KVM doesn't handle LBR and offcore support.
> > So check the related MSRs access right once at initialization time to avoid
> the error access at runtime.
> >
> > For reproducing the issue, please build the kernel with
> CONFIG_KVM_INTEL = y.
> This is for host kernel,
> > And CONFIG_PARAVIRT = n and CONFIG_KVM_GUEST = n.
> And this is for guest kernel, right?
>

Right.


> -Jidong