Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
+14
-3
+7
-3
drivers/vhost/vhost.c
+7
-3
drivers/vhost/vhost.c
···
713
713
r = -EFAULT;
714
714
break;
715
715
}
716
-
if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) ||
717
-
(a.used_user_addr & (sizeof *vq->used->ring - 1)) ||
718
-
(a.log_guest_addr & (sizeof *vq->used->ring - 1))) {
716
+
717
+
/* Make sure it's safe to cast pointers to vring types. */
718
+
BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
719
+
BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
720
+
if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
721
+
(a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
722
+
(a.log_guest_addr & (sizeof(u64) - 1))) {
719
723
r = -EINVAL;
720
724
break;
721
725
}
+7
include/uapi/linux/virtio_ring.h
+7
include/uapi/linux/virtio_ring.h
···
101
101
struct vring_used *used;
102
102
};
103
103
104
+
/* Alignment requirements for vring elements.
105
+
* When using pre-virtio 1.0 layout, these fall out naturally.
106
+
*/
107
+
#define VRING_AVAIL_ALIGN_SIZE 2
108
+
#define VRING_USED_ALIGN_SIZE 4
109
+
#define VRING_DESC_ALIGN_SIZE 16
110
+
104
111
/* The standard layout for the ring is a continuous chunk of memory which looks
105
112
* like this. We assume num is a power of 2.
106
113
*