x86, s3: Sync platform stamps at time suspend.

platform_timer_stamp and stime_platform_stamp are synced
to platform timer in time calibration (1s interval), and
thus doesn't reflect the latest value. If they're not
synced at time suspend, the offset can be lost after S3
resume. Average 0.8s lag-behind is observed for each S3
action, which accumulates to TOD inaccuracy.

Signed-off-by Kevin Tian <kevin.tian@intel.com>

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 806045a3591f75be9a1e0cf04aed2d5efa6413cd..f895ece5e760731aec0ea9c8d36d6e6982009f74 100644 (file)
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -585,8 +585,7 @@ static void resume_platform_timer(void)
     if ( plt_src.resume )
         plt_src.resume(&plt_src);
 
-    /* No change in platform_stime across suspend/resume. */
-    platform_timer_stamp = plt_stamp64;
+    plt_stamp64 = platform_timer_stamp;
     plt_stamp = plt_src.read_counter();
 }
 
@@ -1221,6 +1220,9 @@ int time_suspend(void)
         cmos_utc_offset = -get_cmos_time();
         cmos_utc_offset += (wc_sec + (wc_nsec + NOW()) / 1000000000ULL);
         kill_timer(&calibration_timer);
+
+        /* Sync platform timer stamps. */
+        platform_time_calibration();
     }
 
     /* Better to cancel calibration timer for accuracy. */