KVM: s390: Exploiting generic userspace interface for cmma

[karo-tx-linux.git] / arch / s390 / kvm / kvm-s390.c

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index fc2fe49488c0fc61425847507288e976b1254921..fe2396cc0856232d9334baf4a46f90df2b6e892b 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -258,11 +258,43 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
        return r;
 }
 
+static int kvm_s390_mem_control(struct kvm *kvm, struct kvm_device_attr *attr)
+{
+       int ret;
+       unsigned int idx;
+       switch (attr->attr) {
+       case KVM_S390_VM_MEM_ENABLE_CMMA:
+               ret = -EBUSY;
+               mutex_lock(&kvm->lock);
+               if (atomic_read(&kvm->online_vcpus) == 0) {
+                       kvm->arch.use_cmma = 1;
+                       ret = 0;
+               }
+               mutex_unlock(&kvm->lock);
+               break;
+       case KVM_S390_VM_MEM_CLR_CMMA:
+               mutex_lock(&kvm->lock);
+               idx = srcu_read_lock(&kvm->srcu);
+               page_table_reset_pgste(kvm->arch.gmap->mm, 0, TASK_SIZE, false);
+               srcu_read_unlock(&kvm->srcu, idx);
+               mutex_unlock(&kvm->lock);
+               ret = 0;
+               break;
+       default:
+               ret = -ENXIO;
+               break;
+       }
+       return ret;
+}
+
 static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr)
 {
        int ret;
 
        switch (attr->group) {
+       case KVM_S390_VM_MEM_CTRL:
+               ret = kvm_s390_mem_control(kvm, attr);
+               break;
        default:
                ret = -ENXIO;
                break;
@@ -281,6 +313,17 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
        int ret;
 
        switch (attr->group) {
+       case KVM_S390_VM_MEM_CTRL:
+               switch (attr->attr) {
+               case KVM_S390_VM_MEM_ENABLE_CMMA:
+               case KVM_S390_VM_MEM_CLR_CMMA:
+                       ret = 0;
+                       break;
+               default:
+                       ret = -ENXIO;
+                       break;
+               }
+               break;
        default:
                ret = -ENXIO;
                break;