From mboxrd@z Thu Jan 1 00:00:00 1970 From: stefano.stabellini@eu.citrix.com (Stefano Stabellini) Date: Thu, 5 Nov 2015 17:09:45 +0000 Subject: [PATCH 3/3] xen/arm: set the system time in Xen via the XENPF_settime hypercall In-Reply-To: References: Message-ID: <1446743385-12848-3-git-send-email-stefano.stabellini@eu.citrix.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org If Linux is running as dom0, call XENPF_settime to update the system time in Xen on pvclock_gtod notifications. Signed-off-by: Stefano Stabellini Signed-off-by: Ian Campbell --- arch/arm/xen/enlighten.c | 52 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 51 insertions(+), 1 deletion(-) diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index b6aea9c..0176db0 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -123,6 +124,50 @@ static void xen_read_wallclock(struct timespec *ts) set_normalized_timespec(ts, now.tv_sec, now.tv_nsec); } +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 timespec next_sync; + + struct xen_platform_op op; + struct timespec now; + + now = __current_kernel_time(); + + /* + * We only take the expensive HV call when the clock was set + * or when the 11 minutes RTC synchronization time elapsed. + */ + if (!was_set && timespec_compare(&now, &next_sync) < 0) + return NOTIFY_OK; + + op.interface_version = XENPF_INTERFACE_VERSION; + op.cmd = XENPF_settime; + op.u.settime.secs = now.tv_sec; + op.u.settime.nsecs = now.tv_nsec; + op.u.settime.system_time = arch_timer_read_counter(); + printk("GTOD: Setting to %ld.%ld@%lld\n", + (long)op.u.settime.secs, + (long)op.u.settime.nsecs, + (long long)op.u.settime.system_time); + (void)HYPERVISOR_dom0_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; @@ -321,7 +366,12 @@ static int __init xen_guest_init(void) pv_time_ops.steal_clock = xen_stolen_accounting; static_key_slow_inc(¶virt_steal_enabled); xen_read_wallclock(&ts); - do_settimeofday(&ts); + if (xen_initial_domain()) + pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier); + else { + xen_read_wallclock(&ts); + do_settimeofday(&ts); + } return 0; } -- 1.7.10.4