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Commit 5d9a07b0 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
Browse files

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: default avatarMichael S. Tsirkin <mst@redhat.com>
parent b28e0506

drivers/vhost/vhost.c

+7 −3
Original line number Diff line number Diff line
@@ -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;

		}