From f83c85ee73dfe34c374fb1ab77dfdc2c7e5901b8 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Thu, 10 Mar 2022 15:52:11 +0800 Subject: [PATCH] vhost: allow batching hint without size commit 95932ab2ea07b79cdb33121e2f40ccda9e6a73b5 upstream. 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 Cc: Anirudh Rayabharam Signed-off-by: Jason Wang Link: https://lore.kernel.org/r/20220310075211.4801-1-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin Tested-by: Eli Cohen Signed-off-by: Greg Kroah-Hartman --- 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 55475fd59fb7..6942472cffb0 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; }