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| author |   Juergen Gross <jgross@suse.com> | 2019-01-14 13:44:13 +0100 |
|---|---|---|
| committer |   Boris Ostrovsky <boris.ostrovsky@oracle.com> | 2019-01-16 13:06:05 -0500 |
| commit | 867cefb4cb1012f42cada1c7d1f35ac8dd276071 (patch) | |
| tree | 2f343419e8513ee2cba477e262b4ba7fde507f03 /arch | |
| parent | pvcalls-front: fix potential null dereference (diff) | |
| download | linux-dev-867cefb4cb1012f42cada1c7d1f35ac8dd276071.tar.xz linux-dev-867cefb4cb1012f42cada1c7d1f35ac8dd276071.zip | |
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')
| -rw-r--r-- | arch/x86/xen/time.c | 12 |
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) |