linux-kernel - [PATCH 4.9 027/108] vfio/spapr_tce: Set window when adding additional groups to container

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Message-Id: <20170615175338.483953159@linuxfoundation.org>
Date:   Thu, 15 Jun 2017 19:52:33 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Alexey Kardashevskiy <aik@...abs.ru>,
        David Gibson <david@...son.dropbear.id.au>,
        Alex Williamson <alex.williamson@...hat.com>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.9 027/108] vfio/spapr_tce: Set window when adding additional groups to container

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexey Kardashevskiy <aik@...abs.ru>


[ 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().

Fixes: 6f01cc692a16 ("vfio/spapr: Add a helper to create default DMA window")
Signed-off-by: Alexey Kardashevskiy <aik@...abs.ru>
Reviewed-by: David Gibson <david@...son.dropbear.id.au>
Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/vfio/vfio_iommu_spapr_tce.c |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -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,