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

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Date:	Wed, 2 Jul 2014 22:29:06 -0400
From:	Jidong Xiao <jidong.xiao@...il.com>
To:	kan.liang@...el.com
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Kernel development list <linux-kernel@...r.kernel.org>,
	KVM <kvm@...r.kernel.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?

-Jidong
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