2022-03-10 14:45:04

by Jason Wang

Subject: [PATCH] vhost: allow batching hint without size

Commit e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb
entries") tries to reject the IOTLB message whose size is zero. But
the size is not necessarily meaningful, one example is the batching
hint, so the commit breaks that.

Fixing this be reject zero size message only if the message is used to
update/invalidate the IOTLB.

Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries")
Reported-by: Eli Cohen <[email protected]>
Cc: Anirudh Rayabharam <[email protected]>
Signed-off-by: Jason Wang <[email protected]>
---
drivers/vhost/vhost.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 082380c03a3e..1768362115c6 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1170,7 +1170,9 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
goto done;
}

- if (msg.size == 0) {
+ if ((msg.type == VHOST_IOTLB_UPDATE ||
+ msg.type == VHOST_IOTLB_INVALIDATE) &&
+ msg.size == 0) {
ret = -EINVAL;
goto done;
}
--
2.18.1

2022-03-10 23:14:32

by Eli Cohen

Subject: RE: [PATCH] vhost: allow batching hint without size

Tested-by: Eli Cohen <[email protected]>

> -----Original Message-----
> From: Jason Wang <[email protected]>
> Sent: Thursday, March 10, 2022 9:52 AM
> To: [email protected]
> Cc: [email protected]; [email protected]; [email protected]; [email protected]; Jason Wang
> <[email protected]>; Eli Cohen <[email protected]>; Anirudh Rayabharam <[email protected]>
> Subject: [PATCH] vhost: allow batching hint without size
>
> Commit e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb
> entries") tries to reject the IOTLB message whose size is zero. But
> the size is not necessarily meaningful, one example is the batching
> hint, so the commit breaks that.
>
> Fixing this be reject zero size message only if the message is used to
> update/invalidate the IOTLB.
>
> Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries")
> Reported-by: Eli Cohen <[email protected]>
> Cc: Anirudh Rayabharam <[email protected]>
> Signed-off-by: Jason Wang <[email protected]>
> ---
> drivers/vhost/vhost.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 082380c03a3e..1768362115c6 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -1170,7 +1170,9 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
> goto done;
> }
>
> - if (msg.size == 0) {
> + if ((msg.type == VHOST_IOTLB_UPDATE ||
> + msg.type == VHOST_IOTLB_INVALIDATE) &&
> + msg.size == 0) {
> ret = -EINVAL;
> goto done;
> }
> --
> 2.18.1