KVM: Remove ability to assign a device without iommu support

commit 423873736b78f549fbfa2f715f2e4de7e6c5e1e9 upstream.

This option has no users and it exposes a security hole that we
can allow devices to be assigned without iommu protection.  Make
KVM_DEV_ASSIGN_ENABLE_IOMMU a mandatory option.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
[PG: drop Documentation chunk; no api.txt file in .34 baseline]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index 02ff2b19dbe242a5033da435998a19f1fc4e52ed..1f974738905966d721046ee7182af171b49b1f05 100644 (file)
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -509,6 +509,9 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
        struct kvm_assigned_dev_kernel *match;
        struct pci_dev *dev;
 
+       if (!(assigned_dev->flags & KVM_DEV_ASSIGN_ENABLE_IOMMU))
+               return -EINVAL;
+
        mutex_lock(&kvm->lock);
        idx = srcu_read_lock(&kvm->srcu);
 
@@ -564,16 +567,14 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
 
        list_add(&match->list, &kvm->arch.assigned_dev_head);
 
-       if (assigned_dev->flags & KVM_DEV_ASSIGN_ENABLE_IOMMU) {
-               if (!kvm->arch.iommu_domain) {
-                       r = kvm_iommu_map_guest(kvm);
-                       if (r)
-                               goto out_list_del;
-               }
-               r = kvm_assign_device(kvm, match);
+       if (!kvm->arch.iommu_domain) {
+               r = kvm_iommu_map_guest(kvm);
                if (r)
                        goto out_list_del;
        }
+       r = kvm_assign_device(kvm, match);
+       if (r)
+               goto out_list_del;
 
 out:
        srcu_read_unlock(&kvm->srcu, idx);
@@ -610,8 +611,7 @@ static int kvm_vm_ioctl_deassign_device(struct kvm *kvm,
                goto out;
        }
 
-       if (match->flags & KVM_DEV_ASSIGN_ENABLE_IOMMU)
-               kvm_deassign_device(kvm, match);
+       kvm_deassign_device(kvm, match);
 
        kvm_free_assigned_device(kvm, match);