vhost: introduce vhost memory accessors

This patch introduces vhost memory accessors which were just wrappers
for userspace address access helpers. This is a requirement for vhost
device iotlb implementation which will add iotlb translations in those
accessors.

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

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 0061a7b..e1b5047 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -638,6 +638,22 @@ static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem,
        return 1;
 }
 
+#define vhost_put_user(vq, x, ptr)  __put_user(x, ptr)
+
+static int vhost_copy_to_user(struct vhost_virtqueue *vq, void *to,
+                             const void *from, unsigned size)
+{
+       return __copy_to_user(to, from, size);
+}
+
+#define vhost_get_user(vq, x, ptr) __get_user(x, ptr)
+
+static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
+                               void *from, unsigned size)
+{
+       return __copy_from_user(to, from, size);
+}
+
 static int vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
                        struct vring_desc __user *desc,
                        struct vring_avail __user *avail,
@@ -1143,7 +1159,8 @@ EXPORT_SYMBOL_GPL(vhost_log_write);
 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
 {
        void __user *used;
-       if (__put_user(cpu_to_vhost16(vq, vq->used_flags), &vq->used->flags) < 0)
+       if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
+                          &vq->used->flags) < 0)
                return -EFAULT;
        if (unlikely(vq->log_used)) {
                /* Make sure the flag is seen before log. */
@@ -1161,7 +1178,8 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
 
 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
 {
-       if (__put_user(cpu_to_vhost16(vq, vq->avail_idx), vhost_avail_event(vq)))
+       if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
+                          vhost_avail_event(vq)))
                return -EFAULT;
        if (unlikely(vq->log_used)) {
                void __user *used;
@@ -1199,7 +1217,7 @@ int vhost_vq_init_access(struct vhost_virtqueue *vq)
                r = -EFAULT;
                goto err;
        }
-       r = __get_user(last_used_idx, &vq->used->idx);
+       r = vhost_get_user(vq, last_used_idx, &vq->used->idx);
        if (r)
                goto err;
        vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
@@ -1379,7 +1397,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 
        /* Check it isn't doing very strange things with descriptor numbers. */
        last_avail_idx = vq->last_avail_idx;
-       if (unlikely(__get_user(avail_idx, &vq->avail->idx))) {
+       if (unlikely(vhost_get_user(vq, avail_idx, &vq->avail->idx))) {
                vq_err(vq, "Failed to access avail idx at %p\n",
                       &vq->avail->idx);
                return -EFAULT;
@@ -1401,8 +1419,8 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 
        /* Grab the next descriptor number they're advertising, and increment
         * the index we've seen. */
-       if (unlikely(__get_user(ring_head,
-                               &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
+       if (unlikely(vhost_get_user(vq, ring_head,
+                    &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
                vq_err(vq, "Failed to read head: idx %d address %p\n",
                       last_avail_idx,
                       &vq->avail->ring[last_avail_idx % vq->num]);
@@ -1437,7 +1455,8 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
                               i, vq->num, head);
                        return -EINVAL;
                }
-               ret = __copy_from_user(&desc, vq->desc + i, sizeof desc);
+               ret = vhost_copy_from_user(vq, &desc, vq->desc + i,
+                                          sizeof desc);
                if (unlikely(ret)) {
                        vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
                               i, vq->desc + i);
@@ -1525,15 +1544,15 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,
        start = vq->last_used_idx & (vq->num - 1);
        used = vq->used->ring + start;
        if (count == 1) {
-               if (__put_user(heads[0].id, &used->id)) {
+               if (vhost_put_user(vq, heads[0].id, &used->id)) {
                        vq_err(vq, "Failed to write used id");
                        return -EFAULT;
                }
-               if (__put_user(heads[0].len, &used->len)) {
+               if (vhost_put_user(vq, heads[0].len, &used->len)) {
                        vq_err(vq, "Failed to write used len");
                        return -EFAULT;
                }
-       } else if (__copy_to_user(used, heads, count * sizeof *used)) {
+       } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
                vq_err(vq, "Failed to write used");
                return -EFAULT;
        }
@@ -1577,7 +1596,8 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
 
        /* Make sure buffer is written before we update index. */
        smp_wmb();
-       if (__put_user(cpu_to_vhost16(vq, vq->last_used_idx), &vq->used->idx)) {
+       if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
+                          &vq->used->idx)) {
                vq_err(vq, "Failed to increment used idx");
                return -EFAULT;
        }
@@ -1609,7 +1629,7 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 
        if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
                __virtio16 flags;
-               if (__get_user(flags, &vq->avail->flags)) {
+               if (vhost_get_user(vq, flags, &vq->avail->flags)) {
                        vq_err(vq, "Failed to get flags");
                        return true;
                }
@@ -1623,7 +1643,7 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
        if (unlikely(!v))
                return true;
 
-       if (__get_user(event, vhost_used_event(vq))) {
+       if (vhost_get_user(vq, event, vhost_used_event(vq))) {
                vq_err(vq, "Failed to get used event idx");
                return true;
        }
@@ -1665,7 +1685,7 @@ bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
        __virtio16 avail_idx;
        int r;
 
-       r = __get_user(avail_idx, &vq->avail->idx);
+       r = vhost_get_user(vq, avail_idx, &vq->avail->idx);
        if (r)
                return false;
 
@@ -1700,7 +1720,7 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
        /* They could have slipped one in as we were doing that: make
         * sure it's written, then check again. */
        smp_mb();
-       r = __get_user(avail_idx, &vq->avail->idx);
+       r = vhost_get_user(vq, avail_idx, &vq->avail->idx);
        if (r) {
                vq_err(vq, "Failed to check avail idx at %p: %d\n",
                       &vq->avail->idx, r);