From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH] kvmclock: Ensure time in migration never goes backward
Date: Mon, 5 May 2014 20:31:20 -0300
Message-ID: <20140505233120.GA23113@amt.cnet>
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 <20140505232343.GA20638@amt.cnet>
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To: Alexander Graf <agraf@suse.de>
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On Mon, May 05, 2014 at 08:23:43PM -0300, Marcelo Tosatti wrote:
> Hi Alexander,
> 
> On Mon, May 05, 2014 at 03:51:22PM +0200, Alexander Graf wrote:
> > When we migrate we ask the kernel about its current belief on what the guest
> > time would be. 
> 
> KVM_GET_CLOCK which returns the time in "struct kvm_clock_data".
> 
> > However, I've seen cases where the kvmclock guest structure
> > indicates a time more recent than the kvm returned time.

This should not happen because the value returned by KVM_GET_CLOCK 
(get_kernel_ns() + kvmclock_offset) should be relatively in sync
with what is seen in the guest via kvmclock read.