linux-kernel - Re: GPF in intel_pmu_lbr_reset() with qemu -cpu host

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Date:	Fri, 21 Mar 2014 13:46:04 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Andi Kleen <ak@...ux.intel.com>, Peter Wu <peter@...ensteyn.nl>
CC:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: GPF in intel_pmu_lbr_reset() with qemu -cpu host

Not really.  That is equally braindamaged.  The problem is that KVM is telling the host that our is something it simply cannot be.

On March 21, 2014 12:29:38 PM PDT, Andi Kleen <ak@...ux.intel.com> wrote:
>On Fri, Mar 21, 2014 at 06:42:40PM +0100, Peter Wu wrote:
>> Hi,
>> 
>> While trying to run QEMU with `-enable-kvm -host cpu`, I get a GPF in
>> intel_pmu_lbr_reset():
>
>Same problem as the RAPL problem earlier. KVM is lying to the guest 
>that it is a host CPU, but not implementing all MSRs the host
>CPU supports.
>
>KVM should really return 0 on unknown MSRs not #GP
>
>-Andi

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.
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