* FAILED: patch "[PATCH] vhost: Don't call access_ok() when using IOTLB" failed to apply to 4.14-stable tree
@ 2020-10-09 7:30 gregkh
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From: gregkh @ 2020-10-09 7:30 UTC (permalink / raw)
To: groug, jasowang, mst; +Cc: stable
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 0210a8db2aeca393fb3067e234967877e3146266 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sat, 3 Oct 2020 12:01:52 +0200
Subject: [PATCH] vhost: Don't call access_ok() when using IOTLB
When the IOTLB device is enabled, the vring addresses we get
from userspace are GIOVAs. It is thus wrong to pass them down
to access_ok() which only takes HVAs.
Access validation is done at prefetch time with IOTLB. Teach
vq_access_ok() about that by moving the (vq->iotlb) check
from vhost_vq_access_ok() to vq_access_ok(). This prevents
vhost_vring_set_addr() to fail when verifying the accesses.
No behavior change for vhost_vq_access_ok().
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1883084
Fixes: 6b1e6cc7855b ("vhost: new device IOTLB API")
Cc: jasowang@redhat.com
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Greg Kurz <groug@kaod.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/160171931213.284610.2052489816407219136.stgit@bahia.lan
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b45519ca66a7..c3b49975dc28 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1290,6 +1290,11 @@ static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
vring_used_t __user *used)
{
+ /* If an IOTLB device is present, the vring addresses are
+ * GIOVAs. Access validation occurs at prefetch time. */
+ if (vq->iotlb)
+ return true;
+
return access_ok(desc, vhost_get_desc_size(vq, num)) &&
access_ok(avail, vhost_get_avail_size(vq, num)) &&
access_ok(used, vhost_get_used_size(vq, num));
@@ -1383,10 +1388,6 @@ bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
if (!vq_log_access_ok(vq, vq->log_base))
return false;
- /* Access validation occurs at prefetch time with IOTLB */
- if (vq->iotlb)
- return true;
-
return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
}
EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
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2020-10-09 7:30 FAILED: patch "[PATCH] vhost: Don't call access_ok() when using IOTLB" failed to apply to 4.14-stable tree gregkh
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