This is another iteration for the split pagetable support based on the suggestions from Robin and Will [1].
Background: In order to support per-context pagetables the GPU needs to enable split tables so that we can store global buffers in the TTBR1 space leaving the GPU free to program the TTBR0 register with the address of a context specific pagetable.
If the DOMAIN_ATTR_SPLIT_TABLES attribute is set on the domain before attaching, the context bank assigned to the domain will be programmed to allow translations in the TTBR1 space. Translations in the TTBR0 region will be disallowed because, as Robin pointe out, having a un-programmed TTBR0 register is dangerous.
The driver can determine if TTBR1 was successfully programmed by querying DOMAIN_ATTR_SPLIT_TABLES after attaching. The domain geometry will also be updated to reflect the virtual address space for the TTBR1 range.
Upcoming changes will allow auxiliary domains to be attached to the device which will enable and program TTBR0.
This patchset is based on top of linux-next-20200409
Change log:
v6: Cleanups for the arm-smmu TTBR1 patch from Will Deacon v4: Only program TTBR1 when split pagetables are requested. TTBR0 will be enabled later when an auxiliary domain is attached v3: Remove the implementation specific and make split pagetable support part of the generic configuration
[1] https://lists.linuxfoundation.org/pipermail/iommu/2020-January/041373.html
Jordan Crouse (5): iommu: Add DOMAIN_ATTR_SPLIT_TABLES iommu/arm-smmu: Add support for TTBR1 drm/msm: Attach the IOMMU device during initialization drm/msm: Refactor address space initialization drm/msm/a6xx: Support split pagetables
drivers/gpu/drm/msm/adreno/a2xx_gpu.c | 16 ++++++++ drivers/gpu/drm/msm/adreno/a3xx_gpu.c | 1 + drivers/gpu/drm/msm/adreno/a4xx_gpu.c | 1 + drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 1 + drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 51 ++++++++++++++++++++++++ drivers/gpu/drm/msm/adreno/adreno_gpu.c | 23 ++++++++--- drivers/gpu/drm/msm/adreno/adreno_gpu.h | 8 ++++ drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 18 +++------ drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c | 18 ++++----- drivers/gpu/drm/msm/disp/mdp5/mdp5_cfg.c | 4 -- drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 18 ++++----- drivers/gpu/drm/msm/msm_drv.h | 8 +--- drivers/gpu/drm/msm/msm_gem_vma.c | 36 +++-------------- drivers/gpu/drm/msm/msm_gpu.c | 49 +---------------------- drivers/gpu/drm/msm/msm_gpu.h | 4 +- drivers/gpu/drm/msm/msm_gpummu.c | 6 --- drivers/gpu/drm/msm/msm_iommu.c | 18 +++++---- drivers/gpu/drm/msm/msm_mmu.h | 1 - drivers/iommu/arm-smmu.c | 48 ++++++++++++++++++---- drivers/iommu/arm-smmu.h | 24 ++++++++--- include/linux/iommu.h | 2 + 21 files changed, 200 insertions(+), 155 deletions(-)