From: Peter Zijlstra <peterz@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Eduardo Habkost <ehabkost@redhat.com>,
kvm@vger.kernel.org
Subject: Re: linux 3.13 guest crash with -cpu host
Date: Mon, 3 Feb 2014 15:28:47 +0100 [thread overview]
Message-ID: <20140203142847.GD3229@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140203142642.GK8874@twins.programming.kicks-ass.net>
On Mon, Feb 03, 2014 at 03:26:42PM +0100, Peter Zijlstra wrote:
> On Mon, Feb 03, 2014 at 03:19:18PM +0100, Paolo Bonzini wrote:
> > Il 03/02/2014 15:12, Peter Zijlstra ha scritto:
> > >>> But why doesn't it crash on baremetal?
> > >>> Probably baremetal simply returns 0 or something.
> > >>> Let me try ..
> > >The claim "v2 and above have FEATURE_PDCM" is in fact true for real
> > >hardware.
> > >
> > >If it didn't the rdmsr() would have generated an exception and we'd have
> > >crashed just like your virtual thingy did.
> >
> > Right, and the virt thingy has no PEBS, so there is no correct value that we
> > could return from the MSR. That's why the CPUID bit is zero.
>
> There's more than PEBS in there, there's also the LBR format (which you
> obviously also don't have)
On that.. LBR is purely model based, what do you guys do with those
MSRs?
next prev parent reply other threads:[~2014-02-03 14:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-02 20:59 linux 3.13 guest crash with -cpu host Michael S. Tsirkin
2014-02-03 12:58 ` Eduardo Habkost
2014-02-03 13:29 ` Peter Zijlstra
2014-02-21 21:14 ` [tip:perf/urgent] perf/x86: Correctly use FEATURE_PDCM tip-bot for Peter Zijlstra
2014-02-03 14:06 ` linux 3.13 guest crash with -cpu host Michael S. Tsirkin
2014-02-03 14:07 ` Paolo Bonzini
2014-02-03 14:42 ` Michael S. Tsirkin
2014-02-03 14:12 ` Peter Zijlstra
2014-02-03 14:19 ` Paolo Bonzini
2014-02-03 14:26 ` Peter Zijlstra
2014-02-03 14:28 ` Peter Zijlstra [this message]
2014-02-03 15:01 ` Paolo Bonzini
2014-02-03 14:45 ` Michael S. Tsirkin
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