linux-kernel - RE: [PATCH V2 1/3] perf ignore LBR and offcore

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Message-ID: <37D7C6CF3E00A74B8858931C1DB2F077014BDCCD@SHSMSX103.ccr.corp.intel.com>
Date:	Thu, 3 Jul 2014 04:26:51 +0000
From:	"Liang, Kan" <kan.liang@...el.com>
To:	Jidong Xiao <jidong.xiao@...il.com>
CC:	Peter Zijlstra <peterz@...radead.org>,
	Kernel development list <linux-kernel@...r.kernel.org>,
	KVM <kvm@...r.kernel.org>,
	"andi@...stfloor.org" <andi@...stfloor.org>,
	Andi Kleen <ak@...ux.intel.com>
Subject: RE: [PATCH V2 1/3] perf ignore LBR and offcore_rsp.



> 
> On Wed, Jul 2, 2014 at 2:14 PM,  <kan.liang@...el.com> wrote:
> > From: Kan Liang <kan.liang@...el.com>
> >
> > 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