Patch "vfio/spapr_tce: Set window when adding additional groups to container" has been added to the 4.9-stable tree

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

vfio/spapr_tce: Set window when adding additional groups to container

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-spapr_tce-set-window-when-adding-additional-groups-to-container.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 <[email protected]> know about it.

From: Alexey Kardashevskiy <[email protected]>
Date: Tue, 23 May 2017 21:53:51 -0400
Subject: vfio/spapr_tce: Set window when adding additional groups to container

From: Alexey Kardashevskiy <[email protected]>

[ Upstream commit 930a42ded3fede7ca3acafc9153f4f2d0f56a92c ]

If a container already has a group attached, attaching a new group should just program already created IOMMU tables to the hardware via the iommu_table_group_ops::set_window() callback.

However commit 6f01cc692a16 ("vfio/spapr: Add a helper to create default DMA window") did not just simplify the code but also removed the set_window() calls in the case of attaching groups to a container which already has tables so it broke VFIO PCI hotplug.

This reverts set_window() bits in tce_iommu_take_ownership_ddw().

---
 drivers/vfio/vfio_iommu_spapr_tce.c |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

@@ -1246,6 +1246,8 @@ static void tce_iommu_release_ownership_
 static long tce_iommu_take_ownership_ddw(struct tce_container *container,
 		struct iommu_table_group *table_group)
 {
+	long i, ret = 0;
+
 	if (!table_group->ops->create_table || !table_group->ops->set_window ||
 			!table_group->ops->release_ownership) {
 		WARN_ON_ONCE(1);

@@ -1254,7 +1256,27 @@ static long tce_iommu_take_ownership_ddw
 
 	table_group->ops->take_ownership(table_group);
 
+	/* Set all windows to the new group */
+	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+		struct iommu_table *tbl = container->tables[i];
+
+		if (!tbl)
+			continue;
+
+		ret = table_group->ops->set_window(table_group, i, tbl);
+		if (ret)
+			goto release_exit;
+	}
+
 	return 0;
+
+release_exit:
+	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i)
+		table_group->ops->unset_window(table_group, i);
+
+	table_group->ops->release_ownership(table_group);
+
+	return ret;
 }
 
 static int tce_iommu_attach_group(void *iommu_data,

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/vfio-spapr_tce-set-window-when-adding-additional-groups-to-container.patch