Patch "virtio_balloon: disable VIOMMU support" has been added to the 4.9-stable tree

Patch "virtio_balloon: disable VIOMMU support" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    virtio_balloon: disable VIOMMU support

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     virtio_balloon-disable-viommu-support.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e41b1355508debe45fda33ef8c03ff3ba5d206b9 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Tue, 13 Jun 2017 20:56:44 +0300
Subject: virtio_balloon: disable VIOMMU support

From: Michael S. Tsirkin <mst@redhat.com>

commit e41b1355508debe45fda33ef8c03ff3ba5d206b9 upstream.

virtio balloon bypasses the DMA API entirely so does not support the
VIOMMU right now.  It's not clear we need that support, for now let's
just make sure we don't pretend to support it.

Cc: Wei Wang <wei.w.wang@intel.com>
Fixes: 1a937693993f ("virtio: new feature to detect IOMMU device quirk")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/virtio/virtio_balloon.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -657,6 +657,12 @@ static int virtballoon_restore(struct vi
 }
 #endif
 
+static int virtballoon_validate(struct virtio_device *vdev)
+{
+	__virtio_clear_bit(vdev, VIRTIO_F_IOMMU_PLATFORM);
+	return 0;
+}
+
 static unsigned int features[] = {
 	VIRTIO_BALLOON_F_MUST_TELL_HOST,
 	VIRTIO_BALLOON_F_STATS_VQ,
@@ -669,6 +675,7 @@ static struct virtio_driver virtio_ballo
 	.driver.name =	KBUILD_MODNAME,
 	.driver.owner =	THIS_MODULE,
 	.id_table =	id_table,
+	.validate =	virtballoon_validate,
 	.probe =	virtballoon_probe,
 	.remove =	virtballoon_remove,
 	.config_changed = virtballoon_changed,


Patches currently in stable-queue which might be from mst@redhat.com are

queue-4.9/virtio_balloon-disable-viommu-support.patch

Re: Patch "virtio_balloon: disable VIOMMU support" has been added to the 4.9-stable tree

[Greg KH]

On Mon, Jun 19, 2017 at 09:16:56AM +0800, gregkh@linuxfoundation.org wrote:
> 
> This is a note to let you know that I've just added the patch titled
> 
>     virtio_balloon: disable VIOMMU support
> 
> to the 4.9-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      virtio_balloon-disable-viommu-support.patch
> and it can be found in the queue-4.9 subdirectory.

Oops, no, it breaks the build on 4.9, so it is dropped...