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Re: [Qemu-devel] [PATCH v2] kvmclock: Ensure time in migration never goe
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From: |
Marcelo Tosatti |
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Subject: |
Re: [Qemu-devel] [PATCH v2] kvmclock: Ensure time in migration never goes backward |
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Date: |
Sun, 18 May 2014 10:20:52 -0300 |
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User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, May 16, 2014 at 05:15:21PM +0200, Alexander Graf wrote:
> When we migrate we ask the kernel about its current belief on what the guest
> time would be. However, I've seen cases where the kvmclock guest structure
> indicates a time more recent than the kvm returned time.
>
> To make sure we never go backwards, calculate what the guest would have seen
> as time at the point of migration and use that value instead of the kernel
> returned one when it's more recent.
>
> While the underlying bug is supposedly fixed on newer KVM versions, it doesn't
> hurt to base the view of the kvmclock after migration on the same foundation
> in host as well as guest.
Remove this last phrase from the changelog please, the underlying bug is
not fixed on newer KVM versions.
Otherwise
Reviewed-by: Marcelo Tosatti <address@hidden>