Patch "vfio/powerpc/spapr_tce: Enforce IOMMU type compatibility check" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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

    vfio/powerpc/spapr_tce: Enforce IOMMU type compatibility check

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:
     vfio-powerpc-spapr_tce-enforce-iommu-type-compatibility-check.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 foo@baz Sun Mar 18 16:55:33 CET 2018
From: Alexey Kardashevskiy <aik@ozlabs.ru>
Date: Fri, 24 Mar 2017 17:44:06 +1100
Subject: vfio/powerpc/spapr_tce: Enforce IOMMU type compatibility check

From: Alexey Kardashevskiy <aik@ozlabs.ru>


[ Upstream commit 1282ba7fc28dbc66c3f0e4aaafaaa228361d1ae5 ]

The existing SPAPR TCE driver advertises both VFIO_SPAPR_TCE_IOMMU and
VFIO_SPAPR_TCE_v2_IOMMU types to the userspace and the userspace usually
picks the v2.

Normally the userspace would create a container, attach an IOMMU group
to it and only then set the IOMMU type (which would normally be v2).

However a specific IOMMU group may not support v2, in other words
it may not implement set_window/unset_window/take_ownership/
release_ownership and such a group should not be attached to
a v2 container.

This adds extra checks that a new group can do what the selected IOMMU
type suggests. The userspace can then test the return value from
ioctl(VFIO_SET_IOMMU, VFIO_SPAPR_TCE_v2_IOMMU) and try
VFIO_SPAPR_TCE_IOMMU.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/vfio/vfio_iommu_spapr_tce.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -1332,8 +1332,16 @@ static int tce_iommu_attach_group(void *
 
 	if (!table_group->ops || !table_group->ops->take_ownership ||
 			!table_group->ops->release_ownership) {
+		if (container->v2) {
+			ret = -EPERM;
+			goto unlock_exit;
+		}
 		ret = tce_iommu_take_ownership(container, table_group);
 	} else {
+		if (!container->v2) {
+			ret = -EPERM;
+			goto unlock_exit;
+		}
 		ret = tce_iommu_take_ownership_ddw(container, table_group);
 		if (!tce_groups_attached(container) && !container->tables[0])
 			container->def_window_pending = true;


Patches currently in stable-queue which might be from aik@ozlabs.ru are

queue-4.9/vfio-spapr_tce-check-kzalloc-return-when-preregistering-memory.patch
queue-4.9/vfio-powerpc-spapr_tce-enforce-iommu-type-compatibility-check.patch