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authorJuergen Gross <jgross@suse.com>2019-01-14 13:44:13 +0100
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2019-01-16 13:06:05 -0500
commit867cefb4cb1012f42cada1c7d1f35ac8dd276071 (patch)
tree2f343419e8513ee2cba477e262b4ba7fde507f03 /arch/x86/xen
parentb4711098066f1cf808d4dc11a1a842860a3292fe (diff)
xen: Fix x86 sched_clock() interface for xen
Commit f94c8d11699759 ("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: f94c8d11699759 ("sched/clock, x86/tsc: Rework the x86 'unstable' sched_clock() interface") Cc: <stable@vger.kernel.org> # 4.11 Reported-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com> Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/time.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 72bf446c3fee..6e29794573b7 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -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)