tree 8175716bcd820616bc2fa278d98536de50aa2595
parent bd50cbaa0f34e47c5b82eba1cd1e88143018fa19
author Marcelo Tosatti <mtosatti@redhat.com> 1371598705 -0300
committer Paolo Bonzini <pbonzini@redhat.com> 1372840892 +0200

kvmclock: clock should count only if vm is running

kvmclock should not count while vm is paused, because:

1) if the vm is paused for long periods, timekeeping
math can overflow while converting the (large) clocksource
delta to nanoseconds.

2) Users rely on CLOCK_MONOTONIC to count run time, that is,
time which OS has been in a runnable state (see CLOCK_BOOTTIME).

Change kvmclock driver so as to save clock value when vm transitions
from runnable to stopped state, and to restore clock value from stopped
to runnable transition.

Cc: qemu-stable@nongnu.org
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>