The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 867cefb4cb1012f42cada1c7d1f35ac8dd276071 Mon Sep 17 00:00:00 2001
From: Juergen Gross jgross@suse.com Date: Mon, 14 Jan 2019 13:44:13 +0100 Subject: [PATCH] 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
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) diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 93194f3e7540..117e76b2f939 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -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); }