x86: kvmclock: abstract save/restore sched_clock_state

Upon resume from hibernation, CPU 0's hvclock area contains the old
values for system_time and tsc_timestamp. It is necessary for the
hypervisor to update these values with uptodate ones before the CPU uses
them.

Abstract TSC's save/restore sched_clock_state functions and use
restore_state to write to KVM_SYSTEM_TIME MSR, forcing an update.

Also move restore_sched_clock_state before __restore_processor_state,
since the later calls CONFIG_LOCK_STAT's lockstat_clock (also for TSC).
Thanks to Igor Mammedov for tracking it down.

Fixes suspend-to-disk with kvmclock.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index a62c201c97ec..aed2aa1088f1 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -629,7 +629,7 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
 
 static unsigned long long cyc2ns_suspend;
 
-void save_sched_clock_state(void)
+void tsc_save_sched_clock_state(void)
 {
         if (!sched_clock_stable)
                 return;
@@ -645,7 +645,7 @@ void save_sched_clock_state(void)
  * that sched_clock() continues from the point where it was left off during
  * suspend.
  */
-void restore_sched_clock_state(void)
+void tsc_restore_sched_clock_state(void)
 {
         unsigned long long offset;
         unsigned long flags;