Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

[firefly-linux-kernel-4.4.55.git] / drivers / vhost / vhost.c

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 2ee28266fd0704fd1e1c4c64a6f19c8d863727fd..9e8e004bb1c38d809c2af43b9d42c053db3a41a2 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -36,6 +36,77 @@ enum {
 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
 
+#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
+static void vhost_vq_reset_user_be(struct vhost_virtqueue *vq)
+{
+       vq->user_be = !virtio_legacy_is_little_endian();
+}
+
+static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
+{
+       struct vhost_vring_state s;
+
+       if (vq->private_data)
+               return -EBUSY;
+
+       if (copy_from_user(&s, argp, sizeof(s)))
+               return -EFAULT;
+
+       if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
+           s.num != VHOST_VRING_BIG_ENDIAN)
+               return -EINVAL;
+
+       vq->user_be = s.num;
+
+       return 0;
+}
+
+static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
+                                  int __user *argp)
+{
+       struct vhost_vring_state s = {
+               .index = idx,
+               .num = vq->user_be
+       };
+
+       if (copy_to_user(argp, &s, sizeof(s)))
+               return -EFAULT;
+
+       return 0;
+}
+
+static void vhost_init_is_le(struct vhost_virtqueue *vq)
+{
+       /* Note for legacy virtio: user_be is initialized at reset time
+        * according to the host endianness. If userspace does not set an
+        * explicit endianness, the default behavior is native endian, as
+        * expected by legacy virtio.
+        */
+       vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
+}
+#else
+static void vhost_vq_reset_user_be(struct vhost_virtqueue *vq)
+{
+}
+
+static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
+{
+       return -ENOIOCTLCMD;
+}
+
+static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
+                                  int __user *argp)
+{
+       return -ENOIOCTLCMD;
+}
+
+static void vhost_init_is_le(struct vhost_virtqueue *vq)
+{
+       if (vhost_has_feature(vq, VIRTIO_F_VERSION_1))
+               vq->is_le = true;
+}
+#endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
+
 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
                            poll_table *pt)
 {
@@ -199,6 +270,8 @@ static void vhost_vq_reset(struct vhost_dev *dev,
        vq->call = NULL;
        vq->log_ctx = NULL;
        vq->memory = NULL;
+       vq->is_le = virtio_legacy_is_little_endian();
+       vhost_vq_reset_user_be(vq);
 }
 
 static int vhost_worker(void *data)
@@ -806,6 +879,12 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
                } else
                        filep = eventfp;
                break;
+       case VHOST_SET_VRING_ENDIAN:
+               r = vhost_set_vring_endian(vq, argp);
+               break;
+       case VHOST_GET_VRING_ENDIAN:
+               r = vhost_get_vring_endian(vq, idx, argp);
+               break;
        default:
                r = -ENOIOCTLCMD;
        }
@@ -1044,8 +1123,12 @@ int vhost_init_used(struct vhost_virtqueue *vq)
 {
        __virtio16 last_used_idx;
        int r;
-       if (!vq->private_data)
+       if (!vq->private_data) {
+               vq->is_le = virtio_legacy_is_little_endian();
                return 0;
+       }
+
+       vhost_init_is_le(vq);
 
        r = vhost_update_used_flags(vq);
        if (r)