xen/dom0: set wallclock time in Xen

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 5158c505bef9..8c9cdfa24657 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -200,8 +200,22 @@ static unsigned long xen_get_wallclock(void)
 
 static int xen_set_wallclock(unsigned long now)
 {
+        struct xen_platform_op op;
+        int rc;
+
         /* do nothing for domU */
-        return -1;
+        if (!xen_initial_domain())
+                return -1;
+
+        op.cmd = XENPF_settime;
+        op.u.settime.secs = now;
+        op.u.settime.nsecs = 0;
+        op.u.settime.system_time = xen_clocksource_read();
+
+        rc = HYPERVISOR_dom0_op(&op);
+        WARN(rc != 0, "XENPF_settime failed: now=%ld\n", now);
+
+        return rc;
 }
 
 static struct clocksource xen_clocksource __read_mostly = {