[PATCH 3/3] KVM: s390: use kvm->created_vcpus

[Paolo Bonzini]

The new created_vcpus field avoids possible races between enabling
capabilities and creating VCPUs.

Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
 arch/s390/kvm/kvm-s390.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 43f2a2b80490..a3f845f25eff 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -355,7 +355,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct 
kvm_enable_cap *cap)
                break;
        case KVM_CAP_S390_VECTOR_REGISTERS:
                mutex_lock(&kvm->lock);
-               if (atomic_read(&kvm->online_vcpus)) {
+               if (kvm->created_vcpus) {
                        r = -EBUSY;
                } else if (MACHINE_HAS_VX) {
                        set_kvm_facility(kvm->arch.model.fac_mask, 129);
@@ -370,7 +370,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct 
kvm_enable_cap *cap)
        case KVM_CAP_S390_RI:
                r = -EINVAL;
                mutex_lock(&kvm->lock);
-               if (atomic_read(&kvm->online_vcpus)) {
+               if (kvm->created_vcpus) {
                        r = -EBUSY;
                } else if (test_facility(64)) {
                        set_kvm_facility(kvm->arch.model.fac_mask, 64);
@@ -426,7 +426,7 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct 
kvm_device_attr *att
                ret = -EBUSY;
                VM_EVENT(kvm, 3, "%s", "ENABLE: CMMA support");
                mutex_lock(&kvm->lock);
-               if (atomic_read(&kvm->online_vcpus) == 0) {
+               if (kvm->created_vcpus) {
                        kvm->arch.use_cmma = 1;
                        ret = 0;
                }
@@ -467,7 +467,7 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct 
kvm_device_attr *att
 
                ret = -EBUSY;
                mutex_lock(&kvm->lock);
-               if (atomic_read(&kvm->online_vcpus) == 0) {
+               if (kvm->created_vcpus) {
                        /* gmap_alloc will round the limit up */
                        struct gmap *new = gmap_alloc(current->mm, new_limit);
 
@@ -644,7 +644,7 @@ static int kvm_s390_set_processor(struct kvm *kvm, struct 
kvm_device_attr *attr)
        int ret = 0;
 
        mutex_lock(&kvm->lock);
-       if (atomic_read(&kvm->online_vcpus)) {
+       if (kvm->created_vcpus) {
                ret = -EBUSY;
                goto out;
        }
-- 
1.8.3.1