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From: Gleb Natapov <gleb@kernel.org>
To: Venkatesh Srinivas <venkateshs@google.com>
Cc: Peter Wu <peter@lekensteyn.nl>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>, Andi Kleen <ak@linux.intel.com>,
	Linux Kernel Developers List <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: GPF in intel_pmu_lbr_reset() with qemu -cpu host
Date: Sat, 22 Mar 2014 10:50:45 +0200	[thread overview]
Message-ID: <20140322085045.GA5535@minantech.com> (raw)
In-Reply-To: <CAHdzE-88ZPTs_QvVLZsHs=O6TNKG61+iLH+ctGKLMdG5h6G0sg@mail.gmail.com>

On Fri, Mar 21, 2014 at 12:04:32PM -0700, Venkatesh Srinivas wrote:
> On Fri, Mar 21, 2014 at 10:46 AM, Peter Wu <peter@lekensteyn.nl> wrote:
[skip]

> When -cpu host is used, qemu/kvm passed the host CPUID F/M/S to the
> guest. intel_pmu_cpu_*() -> intel_pmu_lbr_reset() uses rdmsr() /
> wrmsr(), rather than the safe variants; if KVM does not support the
> particular MSRs in question, you will see a #GP(0) there. See
> https://lkml.org/lkml/2014/3/13/453 for a similar bug other PMU code.
> 
When kernel is compiled with guest support all rdmsr()/wrmsr() become _safe(),
so the question for Peter is if his guest kernel has guest support enabled?
 
--
			Gleb.

  parent reply	other threads:[~2014-03-22  8:50 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-21 17:42 GPF in intel_pmu_lbr_reset() with qemu -cpu host Peter Wu
2014-03-21 17:46 ` Peter Wu
2014-03-21 19:04   ` Venkatesh Srinivas
2014-03-21 19:09     ` H. Peter Anvin
2014-03-22  7:54       ` Paolo Bonzini
2014-03-22  8:50     ` Gleb Natapov [this message]
2014-03-22 10:05       ` Peter Wu
2014-03-22 12:27         ` Gleb Natapov
2014-03-22 21:46           ` H. Peter Anvin
2014-03-22 22:00           ` Peter Wu
2014-03-26  7:23             ` Wu, Feng
2014-03-26  9:38               ` Paolo Bonzini
2014-03-21 19:29 ` Andi Kleen
2014-03-21 20:46   ` H. Peter Anvin
2014-03-21 21:37     ` Andi Kleen
2014-03-21 21:41       ` H. Peter Anvin
2014-03-21 21:48         ` Andi Kleen
2014-03-21 21:55           ` H. Peter Anvin
2014-03-22  0:22             ` Andi Kleen
2014-03-22  0:26               ` H. Peter Anvin
2014-03-22  0:30                 ` Andi Kleen
2014-03-22  0:34                   ` H. Peter Anvin
2014-03-22 10:01                     ` Borislav Petkov

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