David Hildenbrand 2d00f75942 KVM: s390: forward hrtimer if guest ckc not pending yet ... Patch 0759d0681c ("KVM: s390: cleanup handle_wait by reusing kvm_vcpu_block") changed the way pending guest clock comparator interrupts are detected. It was assumed that as soon as the hrtimer wakes up, the condition for the guest ckc is satisfied. This is however only true as long as adjclock() doesn't speed up the monotonic clock. Reason is that the hrtimer is based on CLOCK_MONOTONIC, the guest clock comparator detection is based on the raw TOD clock. If CLOCK_MONOTONIC runs faster than the TOD clock, the hrtimer wakes the target VCPU up too early and the target VCPU will not detect any pending interrupts, therefore going back to sleep. It will never be woken up again because the hrtimer has finished. The VCPU is stuck. As a quick fix, we have to forward the hrtimer until the guest clock comparator is really due, to guarantee properly timed wake ups. As the hrtimer callback might be triggered on another cpu, we have to make sure that the timer is really stopped and not currently executing the callback on another cpu. This can happen if the vcpu thread is scheduled onto another physical cpu, but the timer base is not migrated. So lets use hrtimer_cancel instead of try_to_cancel. A proper fix might be to introduce a RAW based hrtimer. Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>		2015-01-23 13:25:32 +01:00
..
diag.c	KVM: s390/cmm: Fix prefix handling for diag 10 balloon	2014-09-10 12:19:42 +02:00
gaccess.c	kernel: Provide READ_ONCE and ASSIGN_ONCE	2014-12-20 16:48:59 -08:00
gaccess.h	KVM: s390: Enable DAT support for TPROT handler	2014-05-30 09:39:36 +02:00
guestdbg.c	KVM: s390: return -EFAULT if copy_from_user() fails	2014-05-06 14:57:59 +02:00
intercept.c	KVM: s390: handle pending local interrupts via bitmap	2014-11-28 13:59:04 +01:00
interrupt.c	KVM: s390: forward hrtimer if guest ckc not pending yet	2015-01-23 13:25:32 +01:00
irq.h	KVM: s390: irq routing for adapter interrupts.	2014-03-21 13:43:00 +01:00
Kconfig	KVM: Give IRQFD its own separate enabling Kconfig option	2014-08-05 14:26:28 +02:00
kvm-s390.c	KVM: s390: base hrtimer on a monotonic clock	2015-01-23 13:25:32 +01:00
kvm-s390.h	KVM: s390: handle pending local interrupts via bitmap	2014-11-28 13:59:04 +01:00
Makefile	KVM: s390: hardware support for guest debugging	2014-04-22 13:24:51 +02:00
priv.c	3.19 changes for KVM:	2014-12-18 16:05:28 -08:00
sigp.c	KVM: s390: handle pending local interrupts via bitmap	2014-11-28 13:59:04 +01:00
trace-s390.h	KVM: s390: enable IBS for single running VCPUs	2014-04-29 15:01:54 +02:00
trace.h	KVM: s390: interpretive execution of SIGP EXTERNAL CALL	2014-05-16 14:57:28 +02:00