[PATCH 3.16.y-ckt 044/183] KVM: s390: base hrtimer on a monotonic clock

Luis Henriques luis.henriques at canonical.com
Fri Mar 6 09:55:35 UTC 2015

3.16.7-ckt8 -stable review patch.  If anyone has any objections, please let me know.


From: David Hildenbrand <dahi at linux.vnet.ibm.com>

commit 0ac96caf0f9381088c673a16d910b1d329670edf upstream.

The hrtimer that handles the wait with enabled timer interrupts
should not be disturbed by changes of the host time.

This patch changes our hrtimer to be based on a monotonic clock.

Signed-off-by: David Hildenbrand <dahi at linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck at de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger at de.ibm.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 arch/s390/kvm/kvm-s390.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 0eaf87281f45..5e9217d96cfe 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -646,7 +646,7 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 		if (rc)
 			return rc;
-	hrtimer_init(&vcpu->arch.ckc_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
+	hrtimer_init(&vcpu->arch.ckc_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	tasklet_init(&vcpu->arch.tasklet, kvm_s390_tasklet,
 		     (unsigned long) vcpu);
 	vcpu->arch.ckc_timer.function = kvm_s390_idle_wakeup;

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