Commit d7e19bd8 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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

Pull vhost cleanup and virtio bugfix
 "There's a single change here, fixing a vhost bug where vhost
  initialization fails due to used ring alignment check being too
  strict"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: relax used address alignment
  virtio_ring: document alignment requirements
parents 5e0f872c 5d9a07b0

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;

		}

include/uapi/linux/virtio_ring.h

+7 −0
Original line number Diff line number Diff line
@@ -101,6 +101,13 @@ struct vring { 
	struct vring_used *used;

};



/* Alignment requirements for vring elements.

 * When using pre-virtio 1.0 layout, these fall out naturally.

 */

#define VRING_AVAIL_ALIGN_SIZE 2

#define VRING_USED_ALIGN_SIZE 4

#define VRING_DESC_ALIGN_SIZE 16



/* The standard layout for the ring is a continuous chunk of memory which looks

 * like this.  We assume num is a power of 2.

 *

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