On 2023/7/25 1:22, Jason Gunthorpe wrote:
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 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-smmu.c G Y IDENTITY IDENTITY virtio-iommu.c Y Y N/A either spapr Y Y N/A N/A PLATFORM * G means ops->identity_domain is used * N/A means the driver will not compile in this configuration ARM32 drivers select an IDENTITY default domain through either the ops->identity_domain or directly requesting an IDENTIY domain through alloc_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 an IDENTITY domain. POWER SPAPR uses PLATFORM and blocking to enable its weird VFIO mode. 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. Tested-by: Heiko Stuebner<he...@sntech.de> Tested-by: Niklas Schnelle<schne...@linux.ibm.com> Tested-by: Steven Price<steven.pr...@arm.com> Tested-by: Marek Szyprowski<m.szyprow...@samsung.com> Tested-by: Nicolin Chen<nicol...@nvidia.com> Signed-off-by: Jason Gunthorpe<j...@nvidia.com> --- drivers/iommu/iommu.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-)
Reviewed-by: Lu Baolu <baolu...@linux.intel.com>
