[PATCH v6 07/20] dma-mapping: make dma_pgprot() honor DMA_ATTR_CC_SHARED
From: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>
Date: 2026-06-04 08:41:25
Also in:
linux-arm-kernel, linux-coco, linux-iommu, linux-s390, lkml
Subsystem:
dma mapping helpers, the rest · Maintainers:
Marek Szyprowski, Linus Torvalds
Fold encrypted/decrypted pgprot selection into dma_pgprot() so callers do not need to adjust the page protection separately. Update dma_pgprot() to apply pgprot_decrypted() when DMA_ATTR_CC_SHARED is set and pgprot_encrypted() otherwise Convert the dma-direct allocation and mmap paths to pass DMA_ATTR_CC_SHARED instead of open-coding force_dma_unencrypted() handling around dma_pgprot(). Tested-by: Jiri Pirko <redacted> Tested-by: Michael Kelley <redacted> Tested-by: Mostafa Saleh <smostafa@google.com> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org> --- kernel/dma/direct.c | 8 +++----- kernel/dma/mapping.c | 16 ++++++++++++---- 2 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 0b4a26c6b6fd..e4cba322386d 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c@@ -290,9 +290,6 @@ void *dma_direct_alloc(struct device *dev, size_t size, if (remap) { pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs); - if (force_dma_unencrypted(dev)) - prot = pgprot_decrypted(prot); - /* remove any dirty cache lines on the kernel alias */ arch_dma_prep_coherent(page, size);
@@ -614,9 +611,10 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma, unsigned long pfn = PHYS_PFN(dma_to_phys(dev, dma_addr)); int ret = -ENXIO; - vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); if (force_dma_unencrypted(dev)) - vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot); + attrs |= DMA_ATTR_CC_SHARED; + + vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) return ret;
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index e6b07f160d20..3f4ae283c466 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c@@ -539,13 +539,21 @@ EXPORT_SYMBOL(dma_get_sgtable_attrs); */ pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs) { + pgprot_t dma_prot; + if (dev_is_dma_coherent(dev)) - return prot; + dma_prot = prot; #ifdef CONFIG_ARCH_HAS_DMA_WRITE_COMBINE - if (attrs & DMA_ATTR_WRITE_COMBINE) - return pgprot_writecombine(prot); + else if (attrs & DMA_ATTR_WRITE_COMBINE) + dma_prot = pgprot_writecombine(prot); #endif - return pgprot_dmacoherent(prot); + else + dma_prot = pgprot_dmacoherent(prot); + + if (attrs & DMA_ATTR_CC_SHARED) + return pgprot_decrypted(dma_prot); + else + return pgprot_encrypted(dma_prot); } #endif /* CONFIG_MMU */
--
2.43.0