[PATCH v3 1/8] iommu: Add ops entry for supported default domain type

Lu Baolu
2019-04-29T02:09:18Z

This adds an optional ops entry to query the default domain
types supported by the iommu driver for a specific device.
This is necessary in cases where the iommu driver can only
support a specific type of default domain for a device. In
normal cases, this ops will return IOMMU_DOMAIN_ANY which
indicates that the iommu driver supports both IOMMU_DOMAIN_DMA
and IOMMU_DOMAIN_IDENTITY, hence the static default domain
type will be used.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/iommu.c | 13 ++++++++++---
include/linux/iommu.h | 11 +++++++++++
2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index acd6830e6e9b..1ad9a1f2e078 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1097,15 +1097,22 @@ struct iommu_group *iommu_group_get_for_dev(struct device *dev)
* IOMMU driver.
*/
if (!group->default_domain) {
+ unsigned int domain_type = IOMMU_DOMAIN_ANY;
struct iommu_domain *dom;

- dom = __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
- if (!dom && iommu_def_domain_type != IOMMU_DOMAIN_DMA) {
+ if (ops->def_domain_type)
+ domain_type = ops->def_domain_type(dev);
+
+ if (domain_type == IOMMU_DOMAIN_ANY)
+ domain_type = iommu_def_domain_type;
+
+ dom = __iommu_domain_alloc(dev->bus, domain_type);
+ if (!dom && domain_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);
+ domain_type);
}
}

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 8239ece9fdfc..ba9a5b996a63 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -79,12 +79,16 @@ struct iommu_domain_geometry {
* IOMMU_DOMAIN_DMA - Internally used for DMA-API implementations.
* This flag allows IOMMU drivers to implement
* certain optimizations for these domains
+ * IOMMU_DOMAIN_ANY - All domain types defined here
*/
#define IOMMU_DOMAIN_BLOCKED (0U)
#define IOMMU_DOMAIN_IDENTITY (__IOMMU_DOMAIN_PT)
#define IOMMU_DOMAIN_UNMANAGED (__IOMMU_DOMAIN_PAGING)
#define IOMMU_DOMAIN_DMA (__IOMMU_DOMAIN_PAGING | \
__IOMMU_DOMAIN_DMA_API)
+#define IOMMU_DOMAIN_ANY (IOMMU_DOMAIN_IDENTITY | \
+ IOMMU_DOMAIN_UNMANAGED | \
+ IOMMU_DOMAIN_DMA)

struct iommu_domain {
unsigned type;
@@ -196,6 +200,11 @@ enum iommu_dev_features {
* @dev_feat_enabled: check enabled feature
* @aux_attach/detach_dev: aux-domain specific attach/detach entries.
* @aux_get_pasid: get the pasid given an aux-domain
+ * @def_domain_type: get per-device default domain type that the IOMMU
+ * driver is able to support. Valid returns values:
+ * - IOMMU_DOMAIN_DMA: only suports non-identity domain
+ * - IOMMU_DOMAIN_IDENTITY: only supports identity domain
+ * - IOMMU_DOMAIN_ANY: supports all
* @pgsize_bitmap: bitmap of all possible supported page sizes
*/
struct iommu_ops {
@@ -251,6 +260,8 @@ struct iommu_ops {
void (*aux_detach_dev)(struct iommu_domain *domain, struct device *dev);
int (*aux_get_pasid)(struct iommu_domain *domain, struct device *dev);

+ int (*def_domain_type)(struct device *dev);
+
unsigned long pgsize_bitmap;
};

--
2.17.1