1 files changed, 14 insertions, 5 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index a353bb43ee48..8fcb56141689 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2380,7 +2380,16 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
 		return -EINVAL;
 	if (mop->size > MEM_OP_MAX_SIZE)
 		return -E2BIG;
-	if (kvm_s390_pv_is_protected(kvm))
+	/*
+	 * This is technically a heuristic only, if the kvm->lock is not
+	 * taken, it is not guaranteed that the vm is/remains non-protected.
+	 * This is ok from a kernel perspective, wrongdoing is detected
+	 * on the access, -EFAULT is returned and the vm may crash the
+	 * next time it accesses the memory in question.
+	 * There is no sane usecase to do switching and a memop on two
+	 * different CPUs at the same time.
+	 */
+	if (kvm_s390_pv_get_handle(kvm))
 		return -EINVAL;
 	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
 		if (access_key_invalid(mop->key))
@@ -4233,14 +4242,14 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
 	 * We try to hold kvm->srcu during most of vcpu_run (except when run-
 	 * ning the guest), so that memslots (and other stuff) are protected
 	 */
-	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+	kvm_vcpu_srcu_read_lock(vcpu);
 
 	do {
 		rc = vcpu_pre_run(vcpu);
 		if (rc)
 			break;
 
-		srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+		kvm_vcpu_srcu_read_unlock(vcpu);
 		/*
 		 * As PF_VCPU will be used in fault handler, between
 		 * guest_enter and guest_exit should be no uaccess.
@@ -4277,12 +4286,12 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
 		__enable_cpu_timer_accounting(vcpu);
 		guest_exit_irqoff();
 		local_irq_enable();
-		vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+		kvm_vcpu_srcu_read_lock(vcpu);
 
 		rc = vcpu_post_run(vcpu, exit_reason);
 	} while (!signal_pending(current) && !guestdbg_exit_pending(vcpu) && !rc);
 
-	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+	kvm_vcpu_srcu_read_unlock(vcpu);
 	return rc;
 }