From: Kan Liang
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
On Mon, Jul 07, 2014 at 06:34:25AM -0700, kan.li...@intel.com wrote:
> + /*
> + * Access LBR MSR may cause #GP under certain circumstances.
> + * E.g. KVM doesn't support LBR MSR
> + * Check all LBT MSR here.
> + * Disable LBR access if any LBR MSRs can not be accessed.
> +
On Mon, Jul 07, 2014 at 06:34:25AM -0700, kan.li...@intel.com wrote:
> @@ -555,7 +577,11 @@ static inline void __x86_pmu_enable_event(struct
> hw_perf_event *hwc,
> {
> u64 disable_mask = __this_cpu_read(cpu_hw_events.perf_ctr_virt_mask);
>
> - if (hwc->extra_reg.reg)
> + if (hwc-
>
> On Mon, Jul 07, 2014 at 06:34:25AM -0700, kan.li...@intel.com wrote:
> > + /*
> > +* Access LBR MSR may cause #GP under certain circumstances.
> > +* E.g. KVM doesn't support LBR MSR
> > +* Check all LBT MSR here.
> > +* Disable LBR access if any LBR MSRs can not be accesse
> -Original Message-
> From: Peter Zijlstra [mailto:pet...@infradead.org]
> Sent: Tuesday, July 08, 2014 5:29 AM
> To: Liang, Kan
> Cc: a...@firstfloor.org; linux-ker...@vger.kernel.org; kvm@vger.kernel.org
> Subject: Re: [PATCH V3 1/2] perf ignore LBR and offcore_rsp
On Tue, Jul 08, 2014 at 02:22:25PM +, Liang, Kan wrote:
> > This too is wrong in many ways; there's more than 2 extra_msrs on many
> > systems.
> >
> Right, there are four extra reg types on Intel systems. Since my
> previous test only triggers the crash with RSP_0 and RSP_1, so I only
> hand
