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Subject[RFC PATCH 02/34] iommu: Add def_domain_type() callback in iommu_ops
Date
From: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>

Some devices are reqired to use a specific type (identity or dma)
of default domain when they are used with a vendor iommu. When the
system level default domain type is different from it, the vendor
iommu driver has to request a new default domain with
iommu_request_dma_domain_for_dev() and iommu_request_dm_for_dev()
in the add_dev() callback. Unfortunately, these two helpers only
work when the group hasn't been assigned to any other devices,
hence, some vendor iommu driver has to use a private domain if
it fails to request a new default one.

This adds def_domain_type() callback in the iommu_ops, so that
any special requirement of default domain for a device could be
aware by the iommu generic layer.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
[ jroedel@suse.de: Added iommu_get_def_domain_type() function and use
it to allocate the default domain ]
Co-developed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/iommu.c | 20 +++++++++++++++++---
include/linux/iommu.h | 6 ++++++
2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index bfe011760ed1..5877abd9b693 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1361,21 +1361,35 @@ struct iommu_group *fsl_mc_device_group(struct device *dev)
}
EXPORT_SYMBOL_GPL(fsl_mc_device_group);

+static int iommu_get_def_domain_type(struct device *dev)
+{
+ const struct iommu_ops *ops = dev->bus->iommu_ops;
+ unsigned int type = 0;
+
+ if (ops->def_domain_type)
+ type = ops->def_domain_type(dev);
+
+ return (type == 0) ? iommu_def_domain_type : type;
+}
+
static int iommu_alloc_default_domain(struct device *dev,
struct iommu_group *group)
{
struct iommu_domain *dom;
+ unsigned int type;

if (group->default_domain)
return 0;

- dom = __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
- if (!dom && iommu_def_domain_type != IOMMU_DOMAIN_DMA) {
+ type = iommu_get_def_domain_type(dev);
+
+ dom = __iommu_domain_alloc(dev->bus, type);
+ if (!dom && type != IOMMU_DOMAIN_DMA) {
dom = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_DMA);
if (dom) {
dev_warn(dev,
"failed to allocate default IOMMU domain of type %u; falling back to IOMMU_DOMAIN_DMA",
- iommu_def_domain_type);
+ type);
}
}

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 7ef8b0bda695..1f027b07e499 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -248,6 +248,10 @@ struct iommu_iotlb_gather {
* @cache_invalidate: invalidate translation caches
* @sva_bind_gpasid: bind guest pasid and mm
* @sva_unbind_gpasid: unbind guest pasid and mm
+ * @def_domain_type: device default domain type, return value:
+ * - IOMMU_DOMAIN_IDENTITY: must use an identity domain
+ * - IOMMU_DOMAIN_DMA: must use a dma domain
+ * - 0: use the default setting
* @pgsize_bitmap: bitmap of all possible supported page sizes
* @owner: Driver module providing these ops
*/
@@ -318,6 +322,8 @@ struct iommu_ops {

int (*sva_unbind_gpasid)(struct device *dev, int pasid);

+ int (*def_domain_type)(struct device *dev);
+
unsigned long pgsize_bitmap;
struct module *owner;
};
--
2.17.1
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