From: Paolo Bonzini <pbonzini@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
Eduardo Habkost <ehabkost@redhat.com>
Cc: kvm@vger.kernel.org, Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: linux 3.13 guest crash with -cpu host
Date: Mon, 03 Feb 2014 15:07:33 +0100 [thread overview]
Message-ID: <52EFA2A5.7000203@redhat.com> (raw)
In-Reply-To: <20140203140601.GA24944@redhat.com>
Il 03/02/2014 15:06, Michael S. Tsirkin ha scritto:
>> Linux seems to be trying to read IA32_PERF_CAPABILITIES without checking the
>> PDCM flag (CPUID[1].ECX[15]).
>>
>> I can't see why this wasn't crashing before, though. That code seems to be old.
>>
>> * v2 and above have a perf capabilities MSR
>> */
>> if (version > 1) {
>> u64 capabilities;
>>
>> rdmsrl(MSR_IA32_PERF_CAPABILITIES, capabilities);
>> x86_pmu.intel_cap.capabilities = capabilities;
>> }
>>
>> Where does the "v2 and above have a perf capabilities MSR" claim in the code
>> come from?
>
>
> But why doesn't it crash on baremetal?
> Probably baremetal simply returns 0 or something.
> Let me try ..
Because KVM doesn't implement the MSR, but your baremetal likely does.
Paolo
next prev parent reply other threads:[~2014-02-03 14:07 UTC|newest]
Thread overview: 12+ 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
2014-02-03 14:06 ` Michael S. Tsirkin
2014-02-03 14:07 ` Paolo Bonzini [this message]
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
2014-02-03 15:01 ` Paolo Bonzini
2014-02-03 14:45 ` Michael S. Tsirkin
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