| Message ID | 1357658590-9123-2-git-send-email-borntraeger@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2013/1/8 Christian Borntraeger <borntraeger@de.ibm.com>: > commit b080935c8638e08134629d0a9ebdf35669bec14d > kvm: Directly account vtime to system on guest switch > > also removed the irq_disable/enable around kvm guest switch, which > is correct in itself. Unfortunately, there is a BUG ON that (correctly) > checks for preemptible to cover the call to rcu later on. > (Introduced with commit 8fa2206821953a50a3a02ea33fcfb3ced2fd9997 > KVM: make guest mode entry to be rcu quiescent state) > > This check might trigger depending on the kernel config. > Lets make sure that no preemption happens during kvm_guest_enter. > We can enable preemption again after the call to > rcu_virt_note_context_switch returns. > > Please note that we continue to run s390 guests with interrupts > enabled. > > CC: Frederic Weisbecker <fweisbec@gmail.com> > CC: Gleb Natapov <gleb@redhat.com> > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > --- > arch/s390/kvm/kvm-s390.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index c9011bf..f090e81 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -613,7 +613,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) > kvm_s390_deliver_pending_interrupts(vcpu); > > vcpu->arch.sie_block->icptcode = 0; > + preempt_disable(); > kvm_guest_enter(); > + preempt_enable(); Sorry for the issue. The fix looks good to me, thanks! Acked-by: Frederic Weisbecker <fweisbec@gmail.com> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 08, 2013 at 04:23:10PM +0100, Christian Borntraeger wrote: > commit b080935c8638e08134629d0a9ebdf35669bec14d > kvm: Directly account vtime to system on guest switch > > also removed the irq_disable/enable around kvm guest switch, which > is correct in itself. Unfortunately, there is a BUG ON that (correctly) > checks for preemptible to cover the call to rcu later on. > (Introduced with commit 8fa2206821953a50a3a02ea33fcfb3ced2fd9997 > KVM: make guest mode entry to be rcu quiescent state) > > This check might trigger depending on the kernel config. > Lets make sure that no preemption happens during kvm_guest_enter. > We can enable preemption again after the call to > rcu_virt_note_context_switch returns. > > Please note that we continue to run s390 guests with interrupts > enabled. > > CC: Frederic Weisbecker <fweisbec@gmail.com> > CC: Gleb Natapov <gleb@redhat.com> > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index c9011bf..f090e81 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -613,7 +613,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) kvm_s390_deliver_pending_interrupts(vcpu); vcpu->arch.sie_block->icptcode = 0; + preempt_disable(); kvm_guest_enter(); + preempt_enable(); VCPU_EVENT(vcpu, 6, "entering sie flags %x", atomic_read(&vcpu->arch.sie_block->cpuflags)); trace_kvm_s390_sie_enter(vcpu,
commit b080935c8638e08134629d0a9ebdf35669bec14d kvm: Directly account vtime to system on guest switch also removed the irq_disable/enable around kvm guest switch, which is correct in itself. Unfortunately, there is a BUG ON that (correctly) checks for preemptible to cover the call to rcu later on. (Introduced with commit 8fa2206821953a50a3a02ea33fcfb3ced2fd9997 KVM: make guest mode entry to be rcu quiescent state) This check might trigger depending on the kernel config. Lets make sure that no preemption happens during kvm_guest_enter. We can enable preemption again after the call to rcu_virt_note_context_switch returns. Please note that we continue to run s390 guests with interrupts enabled. CC: Frederic Weisbecker <fweisbec@gmail.com> CC: Gleb Natapov <gleb@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> --- arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+)