From: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Let's move the finalization of SIGP STOP and SIGP STOP AND STORE STATUS orders to
the point where the VCPU is actually stopped.
This change is needed to prepare for a user space driven VCPU state change. The
action_bits may only be cleared when setting the cpu state to STOPPED while
holding the local irq lock.
Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/kvm/intercept.c | 31 ++++++++++++-------------------
arch/s390/kvm/kvm-s390.c | 8 ++++++++
2 files changed, 20 insertions(+), 19 deletions(-)
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index a0b586c..ac6b325 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -56,32 +56,25 @@ static int handle_noop(struct kvm_vcpu *vcpu)
static int handle_stop(struct kvm_vcpu *vcpu)
{
int rc = 0;
+ unsigned int action_bits;
vcpu->stat.exit_stop_request++;
- spin_lock_bh(&vcpu->arch.local_int.lock);
-
trace_kvm_s390_stop_request(vcpu->arch.local_int.action_bits);
- if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
- kvm_s390_vcpu_stop(vcpu);
- vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
- VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
- rc = -EOPNOTSUPP;
- }
+ action_bits = vcpu->arch.local_int.action_bits;
- if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) {
- vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP;
- /* store status must be called unlocked. Since local_int.lock
- * only protects local_int.* and not guest memory we can give
- * up the lock here */
- spin_unlock_bh(&vcpu->arch.local_int.lock);
+ if (!(action_bits & ACTION_STOP_ON_STOP))
+ return 0;
+
+ if (action_bits & ACTION_STORE_ON_STOP) {
rc = kvm_s390_vcpu_store_status(vcpu,
KVM_S390_STORE_STATUS_NOADDR);
- if (rc >= 0)
- rc = -EOPNOTSUPP;
- } else
- spin_unlock_bh(&vcpu->arch.local_int.lock);
- return rc;
+ if (rc)
+ return rc;
+ }
+
+ kvm_s390_vcpu_stop(vcpu);
+ return -EOPNOTSUPP;
}
static int handle_validity(struct kvm_vcpu *vcpu)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 2f3e14f..c507789 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1494,7 +1494,15 @@ void kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu)
spin_lock_bh(&vcpu->kvm->arch.start_stop_lock);
online_vcpus = atomic_read(&vcpu->kvm->online_vcpus);
+ /* Need to lock access to action_bits to avoid a SIGP race condition */
+ spin_lock_bh(&vcpu->arch.local_int.lock);
atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
+
+ /* SIGP STOP and SIGP STOP AND STORE STATUS has been fully processed */
+ vcpu->arch.local_int.action_bits &=
+ ~(ACTION_STOP_ON_STOP | ACTION_STORE_ON_STOP);
+ spin_unlock_bh(&vcpu->arch.local_int.lock);
+
__disable_ibs_on_vcpu(vcpu);
for (i = 0; i < online_vcpus; i++) {
--
1.8.4.2
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