vhost: factor out setting vring addr and num

Factoring vring address and num setting which needs special care for
accelerating vq metadata accessing.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 103 insertions, 74 deletions

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 30afc79d551e..e27d1da5f979 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1486,6 +1486,104 @@ err:
         return -EFAULT;
 }
 
+static long vhost_vring_set_num(struct vhost_dev *d,
+                                struct vhost_virtqueue *vq,
+                                void __user *argp)
+{
+        struct vhost_vring_state s;
+
+        /* Resizing ring with an active backend?
+         * You don't want to do that. */
+        if (vq->private_data)
+                return -EBUSY;
+
+        if (copy_from_user(&s, argp, sizeof s))
+                return -EFAULT;
+
+        if (!s.num || s.num > 0xffff || (s.num & (s.num - 1)))
+                return -EINVAL;
+        vq->num = s.num;
+
+        return 0;
+}
+
+static long vhost_vring_set_addr(struct vhost_dev *d,
+                                 struct vhost_virtqueue *vq,
+                                 void __user *argp)
+{
+        struct vhost_vring_addr a;
+
+        if (copy_from_user(&a, argp, sizeof a))
+                return -EFAULT;
+        if (a.flags & ~(0x1 << VHOST_VRING_F_LOG))
+                return -EOPNOTSUPP;
+
+        /* For 32bit, verify that the top 32bits of the user
+           data are set to zero. */
+        if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
+            (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
+            (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr)
+                return -EFAULT;
+
+        /* Make sure it's safe to cast pointers to vring types. */
+        BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
+        BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
+        if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
+            (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
+            (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1)))
+                return -EINVAL;
+
+        /* We only verify access here if backend is configured.
+         * If it is not, we don't as size might not have been setup.
+         * We will verify when backend is configured. */
+        if (vq->private_data) {
+                if (!vq_access_ok(vq, vq->num,
+                        (void __user *)(unsigned long)a.desc_user_addr,
+                        (void __user *)(unsigned long)a.avail_user_addr,
+                        (void __user *)(unsigned long)a.used_user_addr))
+                        return -EINVAL;
+
+                /* Also validate log access for used ring if enabled. */
+                if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
+                        !log_access_ok(vq->log_base, a.log_guest_addr,
+                                sizeof *vq->used +
+                                vq->num * sizeof *vq->used->ring))
+                        return -EINVAL;
+        }
+
+        vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
+        vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
+        vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
+        vq->log_addr = a.log_guest_addr;
+        vq->used = (void __user *)(unsigned long)a.used_user_addr;
+
+        return 0;
+}
+
+static long vhost_vring_set_num_addr(struct vhost_dev *d,
+                                     struct vhost_virtqueue *vq,
+                                     unsigned int ioctl,
+                                     void __user *argp)
+{
+        long r;
+
+        mutex_lock(&vq->mutex);
+
+        switch (ioctl) {
+        case VHOST_SET_VRING_NUM:
+                r = vhost_vring_set_num(d, vq, argp);
+                break;
+        case VHOST_SET_VRING_ADDR:
+                r = vhost_vring_set_addr(d, vq, argp);
+                break;
+        default:
+                BUG();
+        }
+
+        mutex_unlock(&vq->mutex);
+
+        return r;
+}
 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
 {
         struct file *eventfp, *filep = NULL;
@@ -1495,7 +1593,6 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
         struct vhost_virtqueue *vq;
         struct vhost_vring_state s;
         struct vhost_vring_file f;
-        struct vhost_vring_addr a;
         u32 idx;
         long r;
 
@@ -1508,26 +1605,14 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
         idx = array_index_nospec(idx, d->nvqs);
         vq = d->vqs[idx];
 
+        if (ioctl == VHOST_SET_VRING_NUM ||
+            ioctl == VHOST_SET_VRING_ADDR) {
+                return vhost_vring_set_num_addr(d, vq, ioctl, argp);
+        }
+
         mutex_lock(&vq->mutex);
 
         switch (ioctl) {
-        case VHOST_SET_VRING_NUM:
-                /* Resizing ring with an active backend?
-                 * You don't want to do that. */
-                if (vq->private_data) {
-                        r = -EBUSY;
-                        break;
-                }
-                if (copy_from_user(&s, argp, sizeof s)) {
-                        r = -EFAULT;
-                        break;
-                }
-                if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
-                        r = -EINVAL;
-                        break;
-                }
-                vq->num = s.num;
-                break;
         case VHOST_SET_VRING_BASE:
                 /* Moving base with an active backend?
                  * You don't want to do that. */
@@ -1553,62 +1638,6 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
                 if (copy_to_user(argp, &s, sizeof s))
                         r = -EFAULT;
                 break;
-        case VHOST_SET_VRING_ADDR:
-                if (copy_from_user(&a, argp, sizeof a)) {
-                        r = -EFAULT;
-                        break;
-                }
-                if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
-                        r = -EOPNOTSUPP;
-                        break;
-                }
-                /* For 32bit, verify that the top 32bits of the user
-                   data are set to zero. */
-                if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
-                    (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
-                    (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
-                        r = -EFAULT;
-                        break;
-                }
-
-                /* Make sure it's safe to cast pointers to vring types. */
-                BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
-                BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
-                if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
-                    (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
-                    (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
-                        r = -EINVAL;
-                        break;
-                }
-
-                /* We only verify access here if backend is configured.
-                 * If it is not, we don't as size might not have been setup.
-                 * We will verify when backend is configured. */
-                if (vq->private_data) {
-                        if (!vq_access_ok(vq, vq->num,
-                                (void __user *)(unsigned long)a.desc_user_addr,
-                                (void __user *)(unsigned long)a.avail_user_addr,
-                                (void __user *)(unsigned long)a.used_user_addr)) {
-                                r = -EINVAL;
-                                break;
-                        }
-
-                        /* Also validate log access for used ring if enabled. */
-                        if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
-                            !log_access_ok(vq->log_base, a.log_guest_addr,
-                                           sizeof *vq->used +
-                                           vq->num * sizeof *vq->used->ring)) {
-                                r = -EINVAL;
-                                break;
-                        }
-                }
-
-                vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
-                vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
-                vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
-                vq->log_addr = a.log_guest_addr;
-                vq->used = (void __user *)(unsigned long)a.used_user_addr;
-                break;
         case VHOST_SET_VRING_KICK:
                 if (copy_from_user(&f, argp, sizeof f)) {
                         r = -EFAULT;