linux.git/drivers/vhost/iotlb.c, branch v5.17

vhost: fix hung thread due to erroneous iotlb entries

2022-03-06T11:05:45+00:00

In vhost_iotlb_add_range_ctx(), range size can overflow to 0 when
start is 0 and last is ULONG_MAX. One instance where it can happen
is when userspace sends an IOTLB message with iova=size=uaddr=0
(vhost_process_iotlb_msg). So, an entry with size = 0, start = 0,
last = ULONG_MAX ends up in the iotlb. Next time a packet is sent,
iotlb_access_ok() loops indefinitely due to that erroneous entry.

	Call Trace:
	 
	 iotlb_access_ok+0x21b/0x3e0 drivers/vhost/vhost.c:1340
	 vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366
	 vhost_transport_do_send_pkt+0xe0/0xfd0 drivers/vhost/vsock.c:104
	 vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372
	 kthread+0x2e9/0x3a0 kernel/kthread.c:377
	 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
	 

Reported by syzbot at:
	https://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87

To fix this, do two things:

1. Return -EINVAL in vhost_chr_write_iter() when userspace asks to map
   a range with size 0.
2. Fix vhost_iotlb_add_range_ctx() to handle the range [0, ULONG_MAX]
   by splitting it into two entries.

Fixes: 0bbe30668d89e ("vhost: factor out IOTLB")
Reported-by: syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com
Tested-by: syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com
Signed-off-by: Anirudh Rayabharam 
Link: https://lore.kernel.org/r/20220305095525.5145-1-mail@anirudhrb.com
Signed-off-by: Michael S. Tsirkin

vhost-iotlb: Add an opaque pointer for vhost IOTLB

2021-09-06T11:20:57+00:00

Add an opaque pointer for vhost IOTLB. And introduce
vhost_iotlb_add_range_ctx() to accept it.

Suggested-by: Jason Wang 
Signed-off-by: Xie Yongji 
Acked-by: Jason Wang 
Link: https://lore.kernel.org/r/20210831103634.33-8-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin

vhost-iotlb: fix vhost_iotlb_del_range() documentation

2021-07-03T08:50:50+00:00

Trivial change for the vhost_iotlb_del_range() documentation,
fixing the function name in the comment block.

Discovered with `make C=2 M=drivers/vhost`:
../drivers/vhost/iotlb.c:92: warning: expecting prototype for vring_iotlb_del_range(). Prototype was for vhost_iotlb_del_range() instead

Signed-off-by: Stefano Garzarella 
Link: https://lore.kernel.org/r/20210504135444.158716-1-sgarzare@redhat.com
Acked-by: Jason Wang 
Signed-off-by: Michael S. Tsirkin

vhost: Fix documentation

2020-09-24T09:54:36+00:00

Fix documentation to match actual function prototypes

"end" used instead of "last". Fix that.

Signed-off-by: Eli Cohen 
Link: https://lore.kernel.org/r/20200630052925.GA157062@mtl-vdi-166.wap.labs.mlnx
Signed-off-by: Michael S. Tsirkin

vhost-iotlb: fix vhost_iotlb_itree_next() documentation

2020-08-26T12:13:59+00:00

This patch contains trivial changes for the vhost_iotlb_itree_next()
documentation, fixing the function name and the description of
first argument (@map).

Signed-off-by: Stefano Garzarella 
Link: https://lore.kernel.org/r/20200825130543.43308-1-sgarzare@redhat.com
Signed-off-by: Michael S. Tsirkin

vhost: factor out IOTLB

2020-04-01T16:06:26+00:00

This patch factors out IOTLB into a dedicated module in order to be
reused by other modules like vringh. User may choose to enable the
automatic retiring by specifying VHOST_IOTLB_FLAG_RETIRE flag to fit
for the case of vhost device IOTLB implementation.

Signed-off-by: Jason Wang 
Link: https://lore.kernel.org/r/20200326140125.19794-4-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin