KVM: arm-vgic: Set base addr through device API

Support setting the distributor and cpu interface base addresses in the
VM physical address space through the KVM_{SET,GET}_DEVICE_ATTR API
in addition to the ARM specific API.

This has the added benefit of being able to share more code in user
space and do things in a uniform manner.

Also deprecate the older API at the same time, but backwards
compatibility will be maintained.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 75 insertions, 12 deletions

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index b15d6c17a090..45db48de4282 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1495,6 +1495,12 @@ static int vgic_ioaddr_assign(struct kvm *kvm, phys_addr_t *ioaddr,
 {
         int ret;
 
+        if (addr & ~KVM_PHYS_MASK)
+                return -E2BIG;
+
+        if (addr & (SZ_4K - 1))
+                return -EINVAL;
+
         if (!IS_VGIC_ADDR_UNDEF(*ioaddr))
                 return -EEXIST;
         if (addr + size < addr)
@@ -1507,26 +1513,41 @@ static int vgic_ioaddr_assign(struct kvm *kvm, phys_addr_t *ioaddr,
         return ret;
 }
 
-int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr)
+/**
+ * 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
+ * @addr:  pointer to address value
+ * @write: if true set the address in the VM address space, if false read the
+ *          address
+ *
+ * Set or get the vgic base addresses for the distributor and the virtual CPU
+ * interface in the VM physical address space.  These addresses are properties
+ * of the emulated core/SoC and therefore user space initially knows this
+ * information.
+ */
+int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 {
         int r = 0;
         struct vgic_dist *vgic = &kvm->arch.vgic;
 
-        if (addr & ~KVM_PHYS_MASK)
-                return -E2BIG;
-
-        if (addr & (SZ_4K - 1))
-                return -EINVAL;
-
         mutex_lock(&kvm->lock);
         switch (type) {
         case KVM_VGIC_V2_ADDR_TYPE_DIST:
-                r = vgic_ioaddr_assign(kvm, &vgic->vgic_dist_base,
-                                       addr, KVM_VGIC_V2_DIST_SIZE);
+                if (write) {
+                        r = vgic_ioaddr_assign(kvm, &vgic->vgic_dist_base,
+                                               *addr, KVM_VGIC_V2_DIST_SIZE);
+                } else {
+                        *addr = vgic->vgic_dist_base;
+                }
                 break;
         case KVM_VGIC_V2_ADDR_TYPE_CPU:
-                r = vgic_ioaddr_assign(kvm, &vgic->vgic_cpu_base,
-                                       addr, KVM_VGIC_V2_CPU_SIZE);
+                if (write) {
+                        r = vgic_ioaddr_assign(kvm, &vgic->vgic_cpu_base,
+                                               *addr, KVM_VGIC_V2_CPU_SIZE);
+                } else {
+                        *addr = vgic->vgic_cpu_base;
+                }
                 break;
         default:
                 r = -ENODEV;
@@ -1538,16 +1559,58 @@ int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr)
 
 static int vgic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 {
+        int r;
+
+        switch (attr->group) {
+        case KVM_DEV_ARM_VGIC_GRP_ADDR: {
+                u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+                u64 addr;
+                unsigned long type = (unsigned long)attr->attr;
+
+                if (copy_from_user(&addr, uaddr, sizeof(addr)))
+                        return -EFAULT;
+
+                r = kvm_vgic_addr(dev->kvm, type, &addr, true);
+                return (r == -ENODEV) ? -ENXIO : r;
+        }
+        }
+
         return -ENXIO;
 }
 
 static int vgic_get_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 {
-        return -ENXIO;
+        int r = -ENXIO;
+
+        switch (attr->group) {
+        case KVM_DEV_ARM_VGIC_GRP_ADDR: {
+                u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+                u64 addr;
+                unsigned long type = (unsigned long)attr->attr;
+
+                r = kvm_vgic_addr(dev->kvm, type, &addr, false);
+                if (r)
+                        return (r == -ENODEV) ? -ENXIO : r;
+
+                if (copy_to_user(uaddr, &addr, sizeof(addr)))
+                        return -EFAULT;
+        }
+        }
+
+        return r;
 }
 
 static int vgic_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 {
+        switch (attr->group) {
+        case KVM_DEV_ARM_VGIC_GRP_ADDR:
+                switch (attr->attr) {
+                case KVM_VGIC_V2_ADDR_TYPE_DIST:
+                case KVM_VGIC_V2_ADDR_TYPE_CPU:
+                        return 0;
+                }
+                break;
+        }
         return -ENXIO;
 }