Re: [PATCH 13/19] drm/msm: Set the global virtual address range from the IOMMU domain

Bjorn Andersson
2020-09-01T05:27:24Z

On Thu 13 Aug 21:41 CDT 2020, Rob Clark wrote:

> From: Jordan Crouse <jcrouse@codeaurora.org>
>
> Use the aperture settings from the IOMMU domain to set up the virtual
> address range for the GPU. This allows us to transparently deal with
> IOMMU side features (like split pagetables).
>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

> Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
> drivers/gpu/drm/msm/adreno/adreno_gpu.c | 13 +++++++++++--
> drivers/gpu/drm/msm/msm_iommu.c | 7 +++++++
> 2 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index 533a34b4cce2..34e6242c1767 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -192,9 +192,18 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
> struct iommu_domain *iommu = iommu_domain_alloc(&platform_bus_type);
> struct msm_mmu *mmu = msm_iommu_new(&pdev->dev, iommu);
> struct msm_gem_address_space *aspace;
> + u64 start, size;
>
> - aspace = msm_gem_address_space_create(mmu, "gpu", SZ_16M,
> - 0xffffffff - SZ_16M);
> + /*
> + * Use the aperture start or SZ_16M, whichever is greater. This will
> + * ensure that we align with the allocated pagetable range while still
> + * allowing room in the lower 32 bits for GMEM and whatnot
> + */
> + start = max_t(u64, SZ_16M, iommu->geometry.aperture_start);
> + size = iommu->geometry.aperture_end - start + 1;
> +
> + aspace = msm_gem_address_space_create(mmu, "gpu",
> + start & GENMASK(48, 0), size);
>
> if (IS_ERR(aspace) && !IS_ERR(mmu))
> mmu->funcs->destroy(mmu);
> diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
> index 3a381a9674c9..1b6635504069 100644
> --- a/drivers/gpu/drm/msm/msm_iommu.c
> +++ b/drivers/gpu/drm/msm/msm_iommu.c
> @@ -36,6 +36,10 @@ static int msm_iommu_map(struct msm_mmu *mmu, uint64_t iova,
> struct msm_iommu *iommu = to_msm_iommu(mmu);
> size_t ret;
>
> + /* The arm-smmu driver expects the addresses to be sign extended */
> + if (iova & BIT_ULL(48))
> + iova |= GENMASK_ULL(63, 49);
> +
> ret = iommu_map_sg(iommu->domain, iova, sgt->sgl, sgt->nents, prot);
> WARN_ON(!ret);
>
> @@ -46,6 +50,9 @@ static int msm_iommu_unmap(struct msm_mmu *mmu, uint64_t iova, size_t len)
> {
> struct msm_iommu *iommu = to_msm_iommu(mmu);
>
> + if (iova & BIT_ULL(48))
> + iova |= GENMASK_ULL(63, 49);
> +
> iommu_unmap(iommu->domain, iova, len);
>
> return 0;
> --
> 2.26.2