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SubjectRe: [Xen-devel] [PATCH v4 6/7] xen/arm: set the system time in Xen via the XENPF_settime64 hypercall
On 12/11/15 17:30, Stefano Stabellini wrote:
> +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.interface_version = XENPF_INTERFACE_VERSION;
> + 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);
> + printk("GTOD: Setting to %llu.%09u at %llu\n",
> + op.u.settime64.secs,
> + op.u.settime64.nsecs,
> + op.u.settime64.system_time);

Is this printk really useful?

> + (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;
> @@ -313,7 +364,9 @@ 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);
> +

I think, you've introduced a trailing whitespace.

> return 0;
> }
> early_initcall(xen_guest_init);
>

Regards,


--
Julien Grall


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