Re: [PATCH kernel] vfio/spapr_tce: Set window when adding additional groups to container

Alex Williamson
2017-02-07T19:35:59Z

On Tue, 7 Feb 2017 17:26:57 +1100
Alexey Kardashevskiy <aik@ozlabs.ru> wrote:

> 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 6f01cc692 "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: 6f01cc692

See Documentation/process/submitting-patches.rst for the expected
format here, 12 char SHA-1 + --oneline summary.

> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> drivers/vfio/vfio_iommu_spapr_tce.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index 7690e5bf3cf1..14c62a8495a2 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -1245,6 +1245,8 @@ static void tce_iommu_release_ownership_ddw(struct tce_container *container,
> 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);
> @@ -1253,7 +1255,26 @@ static long tce_iommu_take_ownership_ddw(struct tce_container *container,
>
> 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];

checkpatch wants a blank line here.

> + 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,

I've fixed these as shown below. David, please review/ack as well and
I'll send a pull for v4.10. Thanks,

Alex

commit c019167838156a2efcc60a15fa4207710bac6e82
Author: Alexey Kardashevskiy <aik@ozlabs.ru>
Date: Tue Feb 7 17:26:57 2017 +1100

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

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@ozlabs.ru>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 7690e5bf3cf1..59b3f62a2d64 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -1245,6 +1245,8 @@ static void tce_iommu_release_ownership_ddw(struct tce_container *container,
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);
@@ -1253,7 +1255,27 @@ static long tce_iommu_take_ownership_ddw(struct tce_container *container,

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,