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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>
This commit is contained in:
Stefano Stabellini 2015-11-23 10:41:12 +00:00 committed by David Vrabel
parent e709fba132
commit 7d5f6f81dd
1 changed files with 48 additions and 0 deletions
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48
arch/arm/xen/enlighten.c
View File

@ -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;
}