Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 49c5a805 authored by Juergen Gross's avatar Juergen Gross Committed by Greg Kroah-Hartman
Browse files

xen: Fix x86 sched_clock() interface for xen 



commit 867cefb4cb1012f42cada1c7d1f35ac8dd276071 upstream.

Commit f94c8d11 ("sched/clock, x86/tsc: Rework the x86 'unstable'
sched_clock() interface") broke Xen guest time handling across
migration:

[  187.249951] Freezing user space processes ... (elapsed 0.001 seconds) done.
[  187.251137] OOM killer disabled.
[  187.251137] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[  187.252299] suspending xenstore...
[  187.266987] xen:grant_table: Grant tables using version 1 layout
[18446743811.706476] OOM killer enabled.
[18446743811.706478] Restarting tasks ... done.
[18446743811.720505] Setting capacity to 16777216

Fix that by setting xen_sched_clock_offset at resume time to ensure a
monotonic clock value.

[boris: replaced pr_info() with pr_info_once() in xen_callback_vector()
 to avoid printing with incorrect timestamp during resume (as we
 haven't re-adjusted the clock yet)]

Fixes: f94c8d11 ("sched/clock, x86/tsc: Rework the x86 'unstable' sched_clock() interface")
Cc: <stable@vger.kernel.org> # 4.11
Reported-by: default avatarHans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Tested-by: default avatarHans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ac0d94ff

arch/x86/xen/time.c

+9 −3
Original line number Diff line number Diff line
@@ -361,8 +361,6 @@ void xen_timer_resume(void) 
{

	int cpu;



	pvclock_resume();



	if (xen_clockevent != &xen_vcpuop_clockevent)

		return;
@@ -379,12 +377,15 @@ static const struct pv_time_ops xen_time_ops __initconst = { 
};



static struct pvclock_vsyscall_time_info *xen_clock __read_mostly;

static u64 xen_clock_value_saved;



void xen_save_time_memory_area(void)

{

	struct vcpu_register_time_memory_area t;

	int ret;



	xen_clock_value_saved = xen_clocksource_read() - xen_sched_clock_offset;



	if (!xen_clock)

		return;
@@ -404,7 +405,7 @@ void xen_restore_time_memory_area(void) 
	int ret;



	if (!xen_clock)

		return;

		goto out;



	t.addr.v = &xen_clock->pvti;
@@ -421,6 +422,11 @@ void xen_restore_time_memory_area(void) 
	if (ret != 0)

		pr_notice("Cannot restore secondary vcpu_time_info (err %d)",

			  ret);



out:

	/* Need pvclock_resume() before using xen_clocksource_read(). */

	pvclock_resume();

	xen_sched_clock_offset = xen_clocksource_read() - xen_clock_value_saved;

}



static void xen_setup_vsyscall_time_info(void)

drivers/xen/events/events_base.c

+1 −1
Original line number Diff line number Diff line
@@ -1650,7 +1650,7 @@ void xen_callback_vector(void) 
			xen_have_vector_callback = 0;

			return;

		}

		pr_info("Xen HVM callback vector for event delivery is enabled\n");

		pr_info_once("Xen HVM callback vector for event delivery is enabled\n");

		alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,

				xen_hvm_callback_vector);

	}