Re: [PATCH 14/18] Fix a possible backwards warp of kvmclock

Rik van Riel
2010-07-15T02:37:00Z

On 07/12/2010 10:25 PM, Zachary Amsden wrote:
> Kernel time, which advances in discrete steps may progress much slower
> than TSC. As a result, when kvmclock is adjusted to a new base, the
> apparent time to the guest, which runs at a much higher, nsec scaled
> rate based on the current TSC, may have already been observed to have
> a larger value (kernel_ns + scaled tsc) than the value to which we are
> setting it (kernel_ns + 0).
>
> We must instead compute the clock as potentially observed by the guest
> for kernel_ns to make sure it does not go backwards.
>
> Signed-off-by: Zachary Amsden<zamsden@redhat.com>

Acked-by: Rik van Riel <riel@redhat.com>

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