iommu: Add IOMMU_DOMAIN_PLATFORM

This is used when the iommu driver is taking control of the dma_ops,
currently only on S390 and power spapr. It is designed to preserve the
original ops->detach_dev() semantic that these S390 was built around.

Provide an opaque domain type and a 'default_domain' ops value that allows
the driver to trivially force any single domain as the default domain.

Update iommufd selftest to use this instead of set_platform_dma_ops

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/2-v8-81230027b2fa+9d-iommu_all_defdom_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 33bd110709072082282aa4b28b7487da120f9fb4..0e13e566581c2142dbf87d1766749091fd04eaef 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -184,6 +184,8 @@ static const char *iommu_domain_type_str(unsigned int t)
        case IOMMU_DOMAIN_DMA:
        case IOMMU_DOMAIN_DMA_FQ:
                return "Translated";
+       case IOMMU_DOMAIN_PLATFORM:
+               return "Platform";
        default:
                return "Unknown";
        }
@@ -1752,6 +1754,17 @@ iommu_group_alloc_default_domain(struct iommu_group *group, int req_type)
 
        lockdep_assert_held(&group->mutex);
 
+       /*
+        * Allow legacy drivers to specify the domain that will be the default
+        * domain. This should always be either an IDENTITY/BLOCKED/PLATFORM
+        * domain. Do not use in new drivers.
+        */
+       if (bus->iommu_ops->default_domain) {
+               if (req_type)
+                       return ERR_PTR(-EINVAL);
+               return bus->iommu_ops->default_domain;
+       }
+
        if (req_type)
                return __iommu_group_alloc_default_domain(bus, group, req_type);
 

diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index d48a202a7c3b81b29083fa4718a9f2b731fe95cd..fb981ba97c4e872aaccbaad8357bdbe248737944 100644 (file)
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -281,14 +281,6 @@ static bool mock_domain_capable(struct device *dev, enum iommu_cap cap)
        return cap == IOMMU_CAP_CACHE_COHERENCY;
 }
 
-static void mock_domain_set_plaform_dma_ops(struct device *dev)
-{
-       /*
-        * mock doesn't setup default domains because we can't hook into the
-        * normal probe path
-        */
-}
-
 static struct iommu_device mock_iommu_device = {
 };
 
@@ -298,12 +290,16 @@ static struct iommu_device *mock_probe_device(struct device *dev)
 }
 
 static const struct iommu_ops mock_ops = {
+       /*
+        * IOMMU_DOMAIN_BLOCKED cannot be returned from def_domain_type()
+        * because it is zero.
+        */
+       .default_domain = &mock_blocking_domain,
        .owner = THIS_MODULE,
        .pgsize_bitmap = MOCK_IO_PAGE_SIZE,
        .hw_info = mock_domain_hw_info,
        .domain_alloc = mock_domain_alloc,
        .capable = mock_domain_capable,
-       .set_platform_dma_ops = mock_domain_set_plaform_dma_ops,
        .device_group = generic_device_group,
        .probe_device = mock_probe_device,
        .default_domain_ops =

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index d0920b2a9f1c0ec988fda20fb29a567c6cfca3bf..a05480be05fd08fb184f2454eb0db69405cc6f4e 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -64,6 +64,7 @@ struct iommu_domain_geometry {
 #define __IOMMU_DOMAIN_DMA_FQ  (1U << 3)  /* DMA-API uses flush queue    */
 
 #define __IOMMU_DOMAIN_SVA     (1U << 4)  /* Shared process address space */
+#define __IOMMU_DOMAIN_PLATFORM        (1U << 5)
 
 #define IOMMU_DOMAIN_ALLOC_FLAGS ~__IOMMU_DOMAIN_DMA_FQ
 /*
@@ -81,6 +82,8 @@ struct iommu_domain_geometry {
  *                               invalidation.
  *     IOMMU_DOMAIN_SVA        - DMA addresses are shared process addresses
  *                               represented by mm_struct's.
+ *     IOMMU_DOMAIN_PLATFORM   - Legacy domain for drivers that do their own
+ *                               dma_api stuff. Do not use in new drivers.
  */
 #define IOMMU_DOMAIN_BLOCKED   (0U)
 #define IOMMU_DOMAIN_IDENTITY  (__IOMMU_DOMAIN_PT)
@@ -91,6 +94,7 @@ struct iommu_domain_geometry {
                                 __IOMMU_DOMAIN_DMA_API |       \
                                 __IOMMU_DOMAIN_DMA_FQ)
 #define IOMMU_DOMAIN_SVA       (__IOMMU_DOMAIN_SVA)
+#define IOMMU_DOMAIN_PLATFORM  (__IOMMU_DOMAIN_PLATFORM)
 
 struct iommu_domain {
        unsigned type;
@@ -262,6 +266,9 @@ struct iommu_iotlb_gather {
  * @owner: Driver module providing these ops
  * @identity_domain: An always available, always attachable identity
  *                   translation.
+ * @default_domain: If not NULL this will always be set as the default domain.
+ *                  This should be an IDENTITY/BLOCKED/PLATFORM domain.
+ *                  Do not use in new drivers.
  */
 struct iommu_ops {
        bool (*capable)(struct device *dev, enum iommu_cap);
@@ -297,6 +304,7 @@ struct iommu_ops {
        unsigned long pgsize_bitmap;
        struct module *owner;
        struct iommu_domain *identity_domain;
+       struct iommu_domain *default_domain;
 };
 
 /**