diff options
| author |   David Hildenbrand <dahi@linux.vnet.ibm.com> | 2014-12-12 12:26:40 +0100 |
|---|---|---|
| committer |   Christian Borntraeger <borntraeger@de.ibm.com> | 2015-01-23 13:25:31 +0100 |
| commit | bda343ef149bc0ce01ec965c74d464849bde96d8 (patch) | |
| tree | b4d5d31b3f759f2e2e7abbd999a2ec6da1b026c3 /arch/s390/kvm | |
| parent | KVM: s390: Allow userspace to limit guest memory size (diff) | |
| download | linux-dev-bda343ef149bc0ce01ec965c74d464849bde96d8.tar.xz linux-dev-bda343ef149bc0ce01ec965c74d464849bde96d8.zip | |
KVM: s390: prevent sleep duration underflows in handle_wait()
We sometimes get an underflow for the sleep duration, which most
likely won't result in the short sleep time we wanted.
So let's check for sleep duration underflows and directly continue
to run the guest if we get one.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/kvm')
| -rw-r--r-- | arch/s390/kvm/interrupt.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index a845e35f904f..5744303c1cde 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -804,14 +804,20 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu) return -EOPNOTSUPP; /* disabled wait */ } - __set_cpu_idle(vcpu); if (!ckc_interrupts_enabled(vcpu)) { VCPU_EVENT(vcpu, 3, "%s", "enabled wait w/o timer"); + __set_cpu_idle(vcpu); goto no_timer; } now = get_tod_clock_fast() + vcpu->arch.sie_block->epoch; sltime = tod_to_ns(vcpu->arch.sie_block->ckc - now); + + /* underflow */ + if (vcpu->arch.sie_block->ckc < now) + return 0; + + __set_cpu_idle(vcpu); hrtimer_start(&vcpu->arch.ckc_timer, ktime_set (0, sltime) , HRTIMER_MODE_REL); VCPU_EVENT(vcpu, 5, "enabled wait via clock comparator: %llx ns", sltime); no_timer: |