@@ -1655,14 +1655,18 @@ iommu_group_alloc_default_domain(struct iommu_group *group, int req_type)
return __iommu_group_alloc_default_domain(bus, group, req_type);
/*
- * ARM32 drivers supporting CONFIG_ARM_DMA_USE_IOMMU can declare an
- * identity_domain and it becomes their default domain. Later on
- * ARM_DMA_USE_IOMMU will install its UNMANAGED domain.
+ * If ARM32 CONFIG_ARM_DMA_USE_IOMMU is enabled and the driver doesn't
+ * use the ops->default_domain override, install an IDENTITY domain as
+ * the default domain. Later on ARM_DMA_USE_IOMMU will install its
+ * UNMANAGED domain.
*/
- if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) &&
- bus->iommu_ops->identity_domain)
+ if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
+ static_assert(!(IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) &&
+ IS_ENABLED(CONFIG_IOMMU_DMA)));
+
return __iommu_group_alloc_default_domain(
bus, group, IOMMU_DOMAIN_IDENTITY);
+ }
/* The driver gave no guidance on what type to use, try the default */
dom = __iommu_group_alloc_default_domain(bus, group, iommu_def_domain_type);
@@ -2848,18 +2852,9 @@ static int iommu_setup_default_domain(struct iommu_group *group,
if (req_type < 0)
return -EINVAL;
- /*
- * There are still some drivers which don't support default domains, so
- * we ignore the failure and leave group->default_domain NULL.
- */
dom = iommu_group_alloc_default_domain(group, req_type);
- if (!dom) {
- /* Once in default_domain mode we never leave */
- if (group->default_domain)
- return -ENODEV;
- group->default_domain = NULL;
- return 0;
- }
+ if (!dom)
+ return -ENODEV;
if (group->default_domain == dom)
return 0;
At this point every iommu driver will cause a default_domain to be selected, so we can finally remove this gap from the core code. The following table explains what each driver supports and what the resulting default_domain will be: ops->defaut_domain IDENTITY DMA PLATFORM v ARM32 dma-iommu ARCH amd/iommu.c Y Y N/A either apple-dart.c Y Y N/A either arm-smmu.c Y Y IDENTITY either qcom_iommu.c G Y IDENTITY either arm-smmu-v3.c Y Y N/A either exynos-iommu.c G Y IDENTITY either fsl_pamu_domain.c Y Y N/A N/A PLATFORM intel/iommu.c Y Y N/A either ipmmu-vmsa.c G Y IDENTITY either msm_iommu.c G IDENTITY N/A mtk_iommu.c G Y IDENTITY either mtk_iommu_v1.c G IDENTITY N/A omap-iommu.c G IDENTITY N/A rockchip-iommu.c G Y IDENTITY either s390-iommu.c Y Y N/A N/A PLATFORM sprd-iommu.c Y N/A DMA sun50i-iommu.c G Y IDENTITY either tegra-gart.c Y Y PLATFORM PLATFORM tegra-smmu.c G Y Y IDENTITY IDENTITY virtio-iommu.c Y Y N/A either * G means ops->identity_domain is used * N/A means the driver will not compile in this configuration ARM32 drivers, except for tegra-gart, select an IDENTITY default domain through either the ops->identity_domain or directly requesting an IDENTIY domain through alloc_domain(). tegra-gart will use its weird PLATFORM domain. In ARM64 mode tegra-smmu will still block the use of dma-iommu.c and forces an IDENTITY domain. S390 uses a PLATFORM domain to represent when the dma_ops are set to the s390 iommu code. fsl_pamu uses a PLATFORM domain. The x86 drivers continue unchanged. After this patch group->default_domain is only NULL for a short period during bus iommu probing while all the groups are constituted. Otherwise it is always !NULL. This completes changing the iommu subsystem driver contract to a system where the current iommu_domain always represents some form of translation and the driver is continuously asserting a definable translation mode. It resolves the confusion that the original ops->detach_dev() caused around what translation, exactly, is the IOMMU performing after detach. There were at least three different answers to that question in the tree, they are all now clearly named with domain types. Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> --- drivers/iommu/iommu.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-)