arm/arm64: KVM: allow userland to request a virtual GICv3

With all of the GICv3 code in place now we allow userland to ask the
kernel for using a virtual GICv3 in the guest.
Also we provide the necessary support for guests setting the memory
addresses for the virtual distributor and redistributors.
This requires some userland code to make use of that feature and
explicitly ask for a virtual GICv3.
Document that KVM_CREATE_IRQCHIP only works for GICv2, but is
considered legacy and using KVM_CREATE_DEVICE is preferred.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

2 files changed, 36 insertions, 13 deletions

diff --git a/virt/kvm/arm/vgic-v3-emul.c b/virt/kvm/arm/vgic-v3-emul.c
index 2d2199d85b74..b3f154631515 100644
--- a/virt/kvm/arm/vgic-v3-emul.c
+++ b/virt/kvm/arm/vgic-v3-emul.c
@@ -1007,6 +1007,9 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
                 case KVM_VGIC_V2_ADDR_TYPE_DIST:
                 case KVM_VGIC_V2_ADDR_TYPE_CPU:
                         return -ENXIO;
+                case KVM_VGIC_V3_ADDR_TYPE_DIST:
+                case KVM_VGIC_V3_ADDR_TYPE_REDIST:
+                        return 0;
                 }
                 break;
         case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 2efba8231375..184c6dbd5165 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1667,7 +1667,7 @@ static int vgic_ioaddr_assign(struct kvm *kvm, phys_addr_t *ioaddr,
 /**
  * kvm_vgic_addr - set or get vgic VM base addresses
  * @kvm:   pointer to the vm struct
- * @type:  the VGIC addr type, one of KVM_VGIC_V2_ADDR_TYPE_XXX
+ * @type:  the VGIC addr type, one of KVM_VGIC_V[23]_ADDR_TYPE_XXX
  * @addr:  pointer to address value
  * @write: if true set the address in the VM address space, if false read the
  *          address
@@ -1681,29 +1681,49 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 {
         int r = 0;
         struct vgic_dist *vgic = &kvm->arch.vgic;
+        int type_needed;
+        phys_addr_t *addr_ptr, block_size;
 
         mutex_lock(&kvm->lock);
         switch (type) {
         case KVM_VGIC_V2_ADDR_TYPE_DIST:
-                if (write) {
-                        r = vgic_ioaddr_assign(kvm, &vgic->vgic_dist_base,
-                                               *addr, KVM_VGIC_V2_DIST_SIZE);
-                } else {
-                        *addr = vgic->vgic_dist_base;
-                }
+                type_needed = KVM_DEV_TYPE_ARM_VGIC_V2;
+                addr_ptr = &vgic->vgic_dist_base;
+                block_size = KVM_VGIC_V2_DIST_SIZE;
                 break;
         case KVM_VGIC_V2_ADDR_TYPE_CPU:
-                if (write) {
-                        r = vgic_ioaddr_assign(kvm, &vgic->vgic_cpu_base,
-                                               *addr, KVM_VGIC_V2_CPU_SIZE);
-                } else {
-                        *addr = vgic->vgic_cpu_base;
-                }
+                type_needed = KVM_DEV_TYPE_ARM_VGIC_V2;
+                addr_ptr = &vgic->vgic_cpu_base;
+                block_size = KVM_VGIC_V2_CPU_SIZE;
                 break;
+#ifdef CONFIG_ARM_GIC_V3
+        case KVM_VGIC_V3_ADDR_TYPE_DIST:
+                type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
+                addr_ptr = &vgic->vgic_dist_base;
+                block_size = KVM_VGIC_V3_DIST_SIZE;
+                break;
+        case KVM_VGIC_V3_ADDR_TYPE_REDIST:
+                type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
+                addr_ptr = &vgic->vgic_redist_base;
+                block_size = KVM_VGIC_V3_REDIST_SIZE;
+                break;
+#endif
         default:
                 r = -ENODEV;
+                goto out;
+        }
+
+        if (vgic->vgic_model != type_needed) {
+                r = -ENODEV;
+                goto out;
         }
 
+        if (write)
+                r = vgic_ioaddr_assign(kvm, addr_ptr, *addr, block_size);
+        else
+                *addr = *addr_ptr;
+
+out:
         mutex_unlock(&kvm->lock);
         return r;
 }