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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-01-02 12:07:50 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-01-02 12:07:50 -0800 |
| commit | d7e19bd882c23109853ac67f414024c816edc8b9 (patch) | |
| tree | 9a302460f9aaa477d8203bd681261e1c1960aa4a | |
| parent | 5e0f872c7d7e371fbdf09e864eddd24bddfda8fe (diff) | |
| parent | 5d9a07b0de512b77bf28d2401e5fe3351f00a240 (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.c | 10 | ||||
| -rw-r--r-- | include/uapi/linux/virtio_ring.h | 7 |
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. * |