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Date: Wed, 4 Jan 2017 09:57:40 -0200
From: Marcelo Tosatti <mtosatti@redhat.com>
Message-ID: <20170104115737.GC14961@amt.cnet>
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Subject: Re: [Qemu-devel] [PATCH 2/4] kvm: Allow invtsc migration if tsc-khz
 is set explicitly
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To: Eduardo Habkost <ehabkost@redhat.com>
Cc: qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org, Haozhong Zhang <haozhong.zhang@intel.com>

On Wed, Jan 04, 2017 at 09:44:06AM -0200, Marcelo Tosatti wrote:
> On Tue, Dec 27, 2016 at 05:21:18PM -0200, Eduardo Habkost wrote:
> > We can safely allow a VM to be migrated with invtsc enabled if
> > tsc-khz is set explicitly, because QEMU already refuses to start
> > if it can't set the TSC frequency to the configured value.
> 
> On the source host, yes, but on the destination it does not.
> 
> SOURCE: -cpu kvm64,tsc-frequency=2660001000
> DESTINATION: -cpu kvm64
> 
> Only prints:
> 
> qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001
> kHz) and host (2893428 kHz), and TSC scaling unavailable
> qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001
> kHz) and host (2893428 kHz), and TSC scaling unavailable
> 
> And allows migration.

Ignore that comment, patch 4 deals with it.