We need to make sure that the timer interrupt happens before we clear
PF_VCPU, so the accounting code actually sees guest mode.

http://lkml.org/lkml/2007/10/15/114Signed-off-by: NLaurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: NAvi Kivity <avi@qumranet.com>