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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2015-11-23 13:41:12 +0300
committerDavid Vrabel <david.vrabel@citrix.com>2015-12-21 17:40:58 +0300
commit7d5f6f81ddbb5b532a832cbeb65472541b22a7c2 (patch)
treea9a8e39e26c595f011f35675cd2a7f36e99324ee
parente709fba132db696bbc21fca2e7f736198ec53eda (diff)
downloadlinux-7d5f6f81ddbb5b532a832cbeb65472541b22a7c2.tar.xz
xen/arm: set the system time in Xen via the XENPF_settime64 hypercall
If Linux is running as dom0, call XENPF_settime64 to update the system time in Xen on pvclock_gtod notifications. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
-rw-r--r--arch/arm/xen/enlighten.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 6370222b8053..75cd7345c654 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -26,7 +26,10 @@
#include <linux/cpufreq.h>
#include <linux/cpu.h>
#include <linux/console.h>
+#include <linux/pvclock_gtod.h>
+#include <linux/time64.h>
#include <linux/timekeeping.h>
+#include <linux/timekeeper_internal.h>
#include <linux/mm.h>
@@ -115,6 +118,49 @@ static void xen_read_wallclock(struct timespec64 *ts)
*ts = timespec64_add(now, ts_monotonic);
}
+static int xen_pvclock_gtod_notify(struct notifier_block *nb,
+ unsigned long was_set, void *priv)
+{
+ /* Protected by the calling core code serialization */
+ static struct timespec64 next_sync;
+
+ struct xen_platform_op op;
+ struct timespec64 now, system_time;
+ struct timekeeper *tk = priv;
+
+ now.tv_sec = tk->xtime_sec;
+ now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
+ system_time = timespec64_add(now, tk->wall_to_monotonic);
+
+ /*
+ * We only take the expensive HV call when the clock was set
+ * or when the 11 minutes RTC synchronization time elapsed.
+ */
+ if (!was_set && timespec64_compare(&now, &next_sync) < 0)
+ return NOTIFY_OK;
+
+ op.cmd = XENPF_settime64;
+ op.u.settime64.mbz = 0;
+ op.u.settime64.secs = now.tv_sec;
+ op.u.settime64.nsecs = now.tv_nsec;
+ op.u.settime64.system_time = timespec64_to_ns(&system_time);
+ (void)HYPERVISOR_platform_op(&op);
+
+ /*
+ * Move the next drift compensation time 11 minutes
+ * ahead. That's emulating the sync_cmos_clock() update for
+ * the hardware RTC.
+ */
+ next_sync = now;
+ next_sync.tv_sec += 11 * 60;
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block xen_pvclock_gtod_notifier = {
+ .notifier_call = xen_pvclock_gtod_notify,
+};
+
static void xen_percpu_init(void)
{
struct vcpu_register_vcpu_info info;
@@ -311,6 +357,8 @@ static int __init xen_guest_init(void)
pv_time_ops.steal_clock = xen_stolen_accounting;
static_key_slow_inc(&paravirt_steal_enabled);
+ if (xen_initial_domain())
+ pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
return 0;
}