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From: Eric Auger <eric.auger@redhat.com>
To: eric.auger.pro@gmail.com, eric.auger@redhat.com, elic@nvidia.com,
	mail@anirudhrb.com, jasowang@redhat.com, mst@redhat.com,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	netdev@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	kvmarm@lists.linux.dev
Cc: stable@vger.kernel.org
Subject: [RESEND PATCH v2] vhost: Allow null msg.size on VHOST_IOTLB_INVALIDATE
Date: Wed, 27 Sep 2023 16:05:44 +0200	[thread overview]
Message-ID: <20230927140544.205088-1-eric.auger@redhat.com> (raw)

Commit e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb
entries") Forbade vhost iotlb msg with null size to prevent entries
with size = start = 0 and last = ULONG_MAX to end up in the iotlb.

Then commit 95932ab2ea07 ("vhost: allow batching hint without size")
only applied the check for VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE
message types to fix a regression observed with batching hit.

Still, the introduction of that check introduced a regression for
some users attempting to invalidate the whole ULONG_MAX range by
setting the size to 0. This is the case with qemu/smmuv3/vhost
integration which does not work anymore. It Looks safe to partially
revert the original commit and allow VHOST_IOTLB_INVALIDATE messages
with null size. vhost_iotlb_del_range() will compute a correct end
iova. Same for vhost_vdpa_iotlb_unmap().

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries")
Cc: stable@vger.kernel.org # v5.17+
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vhost.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c71d573f1c94..e0c181ad17e3 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1458,9 +1458,7 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
 		goto done;
 	}
 
-	if ((msg.type == VHOST_IOTLB_UPDATE ||
-	     msg.type == VHOST_IOTLB_INVALIDATE) &&
-	     msg.size == 0) {
+	if (msg.type == VHOST_IOTLB_UPDATE && msg.size == 0) {
 		ret = -EINVAL;
 		goto done;
 	}
-- 
2.41.0


WARNING: multiple messages have this Message-ID (diff)
From: Eric Auger <eric.auger@redhat.com>
To: eric.auger.pro@gmail.com, eric.auger@redhat.com, elic@nvidia.com,
	mail@anirudhrb.com, jasowang@redhat.com, mst@redhat.com,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	netdev@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	kvmarm@lists.linux.dev
Cc: stable@vger.kernel.org
Subject: [RESEND PATCH v2] vhost: Allow null msg.size on VHOST_IOTLB_INVALIDATE
Date: Wed, 27 Sep 2023 16:05:44 +0200	[thread overview]
Message-ID: <20230927140544.205088-1-eric.auger@redhat.com> (raw)

Commit e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb
entries") Forbade vhost iotlb msg with null size to prevent entries
with size = start = 0 and last = ULONG_MAX to end up in the iotlb.

Then commit 95932ab2ea07 ("vhost: allow batching hint without size")
only applied the check for VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE
message types to fix a regression observed with batching hit.

Still, the introduction of that check introduced a regression for
some users attempting to invalidate the whole ULONG_MAX range by
setting the size to 0. This is the case with qemu/smmuv3/vhost
integration which does not work anymore. It Looks safe to partially
revert the original commit and allow VHOST_IOTLB_INVALIDATE messages
with null size. vhost_iotlb_del_range() will compute a correct end
iova. Same for vhost_vdpa_iotlb_unmap().

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries")
Cc: stable@vger.kernel.org # v5.17+
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vhost.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c71d573f1c94..e0c181ad17e3 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1458,9 +1458,7 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
 		goto done;
 	}
 
-	if ((msg.type == VHOST_IOTLB_UPDATE ||
-	     msg.type == VHOST_IOTLB_INVALIDATE) &&
-	     msg.size == 0) {
+	if (msg.type == VHOST_IOTLB_UPDATE && msg.size == 0) {
 		ret = -EINVAL;
 		goto done;
 	}
-- 
2.41.0

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             reply	other threads:[~2023-09-27 14:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-27 14:05 Eric Auger [this message]
2023-09-27 14:05 ` [RESEND PATCH v2] vhost: Allow null msg.size on VHOST_IOTLB_INVALIDATE Eric Auger
2023-10-16  7:18 ` Eric Auger
2023-10-16  7:18   ` Eric Auger

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