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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Thu, 31 Mar 2016 15:23:05 +0200
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Subject: Re: [Qemu-devel] [Qemu-stable] [PATCH] target-i386: do not
 read/write MSR_TSC_AUX from KVM if CPUID bit is not set
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To: Peter Lieven <pl@kamp.de>, Laszlo Ersek <lersek@redhat.com>, qemu-devel@nongnu.org
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>, ehabkost@redhat.com, qemu-stable@nongnu.org



On 31/03/2016 15:12, Peter Lieven wrote:
>>
>>> KVM does not let you read or write this MSR if the corresponding CPUID
>>> bit is not set.  This in turn causes MSRs that come after MSR_TSC_AUX
>>> to be ignored by KVM_SET_MRSS.
> 
> Is it possible that this causes a freeze when migrating vom qemu 2.2.0
> to 2.5.1?

I wouldn't exclude it if the CPU model is Westmere or earlier.

Paolo