summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-01-02 12:07:50 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-01-02 12:07:50 -0800
commitd7e19bd882c23109853ac67f414024c816edc8b9 (patch)
tree9a302460f9aaa477d8203bd681261e1c1960aa4a
parent5e0f872c7d7e371fbdf09e864eddd24bddfda8fe (diff)
parent5d9a07b0de512b77bf28d2401e5fe3351f00a240 (diff)
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
-rw-r--r--drivers/vhost/vhost.c10
-rw-r--r--include/uapi/linux/virtio_ring.h7
2 files changed, 14 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;
}
diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
index 61c818a7fe70..a3318f31e8e7 100644
--- a/include/uapi/linux/virtio_ring.h
+++ b/include/uapi/linux/virtio_ring.h
@@ -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.
*