[Xen-changelog] Periodically sytnchronize Xen's wallclock time with NTP-synchronized time in domain0.

[Xen patchbot -unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 5541ea99106a32d2b11809bf4d3366dc6eddb93d
# Parent  af6a564ea81c9cfde03d728d691bbe27086bdd7a
Periodically sytnchronize Xen's wallclock time with NTP-synchronized time in 
domain0.

Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>

diff -r af6a564ea81c -r 5541ea99106a 
linux-2.6-xen-sparse/arch/i386/kernel/time-xen.c
--- a/linux-2.6-xen-sparse/arch/i386/kernel/time-xen.c  Sun Feb 26 09:55:21 2006
+++ b/linux-2.6-xen-sparse/arch/i386/kernel/time-xen.c  Sun Feb 26 15:38:59 2006
@@ -487,14 +487,45 @@
 
 EXPORT_SYMBOL(do_settimeofday);
 
-#ifdef CONFIG_XEN_PRIVILEGED_GUEST
+static void sync_xen_wallclock(unsigned long dummy);
+static DEFINE_TIMER(sync_xen_wallclock_timer, sync_xen_wallclock, 0, 0);
+static void sync_xen_wallclock(unsigned long dummy)
+{
+       time_t sec;
+       s64 nsec;
+       dom0_op_t op;
+
+       if (!ntp_synced() || independent_wallclock ||
+           !(xen_start_info->flags & SIF_INITDOMAIN))
+               return;
+
+       write_seqlock_irq(&xtime_lock);
+
+       sec  = xtime.tv_sec;
+       nsec = xtime.tv_nsec + ((jiffies - wall_jiffies) * (u64)NS_PER_TICK);
+       __normalize_time(&sec, &nsec);
+
+       op.cmd = DOM0_SETTIME;
+       op.u.settime.secs        = sec;
+       op.u.settime.nsecs       = nsec;
+       op.u.settime.system_time = processed_system_time;
+       HYPERVISOR_dom0_op(&op);
+
+       update_wallclock();
+
+       write_sequnlock_irq(&xtime_lock);
+
+       /* Once per minute. */
+       mod_timer(&sync_xen_wallclock_timer, jiffies + 60*HZ);
+}
+
 static int set_rtc_mmss(unsigned long nowtime)
 {
        int retval;
 
        WARN_ON(irqs_disabled());
 
-       if (!(xen_start_info->flags & SIF_INITDOMAIN))
+       if (independent_wallclock || !(xen_start_info->flags & SIF_INITDOMAIN))
                return 0;
 
        /* gets recalled with irq locally disabled */
@@ -507,12 +538,6 @@
 
        return retval;
 }
-#else
-static int set_rtc_mmss(unsigned long nowtime)
-{
-       return 0;
-}
-#endif
 
 /* monotonic_clock(): returns # of nanoseconds passed since time_init()
  *             Note: This function is required to return accurate
@@ -768,6 +793,7 @@
 void notify_arch_cmos_timer(void)
 {
        mod_timer(&sync_cmos_timer, jiffies + 1);
+       mod_timer(&sync_xen_wallclock_timer, jiffies + 1);
 }
 
 static long clock_cmos_diff, sleep_start;

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