diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2014-12-21 00:00:23 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2014-12-29 09:55:06 +0100 |
| commit | 5d9a07b0de512b77bf28d2401e5fe3351f00a240 (patch) | |
| tree | 1157d5803702f242d4b35268644ee48e20719307 /drivers/vhost | |
| parent | virtio_ring: document alignment requirements (diff) | |
| download | linux-5d9a07b0de512b77bf28d2401e5fe3351f00a240.tar.xz linux-5d9a07b0de512b77bf28d2401e5fe3351f00a240.zip | |
vhost: relax used address alignment
virtio 1.0 only requires used address to be 4 byte aligned,
vhost required 8 bytes (size of vring_used_elem).
Fix up vhost to match that.
Additionally, while vhost correctly requires 8 byte
alignment for log, it's unconnected to used ring:
it's a consequence that log has u64 entries.
Tweak code to make that clearer.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/vhost')
| -rw-r--r-- | drivers/vhost/vhost.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index ed71b5347a76..cb807d0ea498 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -713,9 +713,13 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) r = -EFAULT; break; } - if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || - (a.used_user_addr & (sizeof *vq->used->ring - 1)) || - (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { + + /* 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 & (sizeof(u64) - 1))) { r = -EINVAL; break; } |