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authorChristian Borntraeger <borntraeger@de.ibm.com>2013-01-08 16:23:10 +0100
committerMarcelo Tosatti <mtosatti@redhat.com>2013-01-10 17:53:40 -0200
commit83987ace22f541964bd0dbf83a3f6b0014ba3e1e (patch)
tree993883209b2b0a03e64cfe3282c29b1dbe7170be /arch/s390
parentecf02a607bd801e742d7bb35c6e40f7ca15edf03 (diff)
downloadvexpress-lsk-83987ace22f541964bd0dbf83a3f6b0014ba3e1e.tar.gz
s390/kvm: Fix BUG in include/linux/kvm_host.h:745
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. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> CC: Gleb Natapov <gleb@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kvm/kvm-s390.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index c9011bfaabb..f090e819bf7 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,