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Subject[PATCH 4.9 68/93] vfio/spapr: Add a helper to create default DMA window
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ Upstream commit 6f01cc692a16405235d5c34056455b182682123c ]

There is already a helper to create a DMA window which does allocate
a table and programs it to the IOMMU group. However
tce_iommu_take_ownership_ddw() did not use it and did these 2 calls
itself to simplify error path.

Since we are going to delay the default window creation till
the default window is accessed/removed or new window is added,
we need a helper to create a default window from all these cases.

This adds tce_iommu_create_default_window(). Since it relies on
a VFIO container to have at least one IOMMU group (for future use),
this changes tce_iommu_attach_group() to add a group to the container
first and then call the new helper.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/vfio/vfio_iommu_spapr_tce.c | 87 +++++++++++++++++-------------------
1 file changed, 42 insertions(+), 45 deletions(-)

--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -784,6 +784,29 @@ static long tce_iommu_remove_window(stru
return 0;
}

+static long tce_iommu_create_default_window(struct tce_container *container)
+{
+ long ret;
+ __u64 start_addr = 0;
+ struct tce_iommu_group *tcegrp;
+ struct iommu_table_group *table_group;
+
+ if (!tce_groups_attached(container))
+ return -ENODEV;
+
+ tcegrp = list_first_entry(&container->group_list,
+ struct tce_iommu_group, next);
+ table_group = iommu_group_get_iommudata(tcegrp->grp);
+ if (!table_group)
+ return -ENODEV;
+
+ ret = tce_iommu_create_window(container, IOMMU_PAGE_SHIFT_4K,
+ table_group->tce32_size, 1, &start_addr);
+ WARN_ON_ONCE(!ret && start_addr);
+
+ return ret;
+}
+
static long tce_iommu_ioctl(void *iommu_data,
unsigned int cmd, unsigned long arg)
{
@@ -1199,9 +1222,6 @@ 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;
- struct iommu_table *tbl = NULL;
-
if (!table_group->ops->create_table || !table_group->ops->set_window ||
!table_group->ops->release_ownership) {
WARN_ON_ONCE(1);
@@ -1210,47 +1230,7 @@ static long tce_iommu_take_ownership_ddw

table_group->ops->take_ownership(table_group);

- /*
- * If it the first group attached, check if there is
- * a default DMA window and create one if none as
- * the userspace expects it to exist.
- */
- if (!tce_groups_attached(container) && !container->tables[0]) {
- ret = tce_iommu_create_table(container,
- table_group,
- 0, /* window number */
- IOMMU_PAGE_SHIFT_4K,
- table_group->tce32_size,
- 1, /* default levels */
- &tbl);
- if (ret)
- goto release_exit;
- else
- container->tables[0] = tbl;
- }
-
- /* Set all windows to the new group */
- for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
- tbl = container->tables[i];
-
- if (!tbl)
- continue;
-
- /* Set the default window to a new group */
- 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,
@@ -1260,6 +1240,7 @@ static int tce_iommu_attach_group(void *
struct tce_container *container = iommu_data;
struct iommu_table_group *table_group;
struct tce_iommu_group *tcegrp = NULL;
+ bool create_default_window = false;

mutex_lock(&container->lock);

@@ -1302,14 +1283,30 @@ static int tce_iommu_attach_group(void *
}

if (!table_group->ops || !table_group->ops->take_ownership ||
- !table_group->ops->release_ownership)
+ !table_group->ops->release_ownership) {
ret = tce_iommu_take_ownership(container, table_group);
- else
+ } else {
ret = tce_iommu_take_ownership_ddw(container, table_group);
+ if (!tce_groups_attached(container) && !container->tables[0])
+ create_default_window = true;
+ }

if (!ret) {
tcegrp->grp = iommu_group;
list_add(&tcegrp->next, &container->group_list);
+ /*
+ * If it the first group attached, check if there is
+ * a default DMA window and create one if none as
+ * the userspace expects it to exist.
+ */
+ if (create_default_window) {
+ ret = tce_iommu_create_default_window(container);
+ if (ret) {
+ list_del(&tcegrp->next);
+ tce_iommu_release_ownership_ddw(container,
+ table_group);
+ }
+ }
}

unlock_exit:

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