tree c5d6b29bb6c8658c3310fc91d0a6a4ccb8c4f99c
parent aea218f3cbbcaac249b6b2c98930a00d6d931f1e
author Bruce Rogers <brogers@suse.com> 1342802664 -0600
committer Marcelo Tosatti <mtosatti@redhat.com> 1343852630 -0300

KVM: x86: apply kvmclock offset to guest wall clock time

When a guest migrates to a new host, the system time difference from the
previous host is used in the updates to the kvmclock system time visible
to the guest, resulting in a continuation of correct kvmclock based guest
timekeeping.

The wall clock component of the kvmclock provided time is currently not
updated with this same time offset. Since the Linux guest caches the
wall clock based time, this discrepency is not noticed until the guest is
rebooted. After reboot the guest's time calculations are off.

This patch adjusts the wall clock by the kvmclock_offset, resulting in
correct guest time after a reboot.

Cc: Zachary Amsden <zamsden@gmail.com>
Signed-off-by: Bruce Rogers <brogers@suse.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>