From: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel•org>
To: iommu@lists•linux.dev, linux-arm-kernel@lists•infradead.org,
linux-kernel@vger•kernel.org, linux-coco@lists•linux.dev
Cc: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel•org>,
Robin Murphy <robin.murphy@arm•com>,
Marek Szyprowski <m.szyprowski@samsung•com>,
Will Deacon <will@kernel•org>, Marc Zyngier <maz@kernel•org>,
Steven Price <steven.price@arm•com>,
Suzuki K Poulose <Suzuki.Poulose@arm•com>,
Catalin Marinas <catalin.marinas@arm•com>,
Jiri Pirko <jiri@resnulli•us>, Jason Gunthorpe <jgg@ziepe•ca>,
Mostafa Saleh <smostafa@google•com>,
Petr Tesarik <ptesarik@suse•com>,
Alexey Kardashevskiy <aik@amd•com>,
Dan Williams <dan.j.williams@intel•com>,
Xu Yilun <yilun.xu@linux•intel.com>,
linuxppc-dev@lists•ozlabs.org, linux-s390@vger•kernel.org,
Madhavan Srinivasan <maddy@linux•ibm.com>,
Michael Ellerman <mpe@ellerman•id.au>,
Nicholas Piggin <npiggin@gmail•com>,
"Christophe Leroy (CS GROUP)" <chleroy@kernel•org>,
Alexander Gordeev <agordeev@linux•ibm.com>,
Gerald Schaefer <gerald.schaefer@linux•ibm.com>,
Heiko Carstens <hca@linux•ibm.com>,
Vasily Gorbik <gor@linux•ibm.com>,
Christian Borntraeger <borntraeger@linux•ibm.com>,
Sven Schnelle <svens@linux•ibm.com>,
x86@kernel•org, Jiri Pirko <jiri@nvidia•com>,
Michael Kelley <mhklinux@outlook•com>
Subject: [PATCH v6 11/20] dma-direct: select DMA address encoding from DMA_ATTR_CC_SHARED
Date: Thu, 4 Jun 2026 14:09:50 +0530 [thread overview]
Message-ID: <20260604083959.1265923-12-aneesh.kumar@kernel.org> (raw)
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Make the dma-direct helpers derive the DMA address encoding from
DMA_ATTR_CC_SHARED instead of implicitly relying on
force_dma_unencrypted() inside phys_to_dma_direct()
Pass an explicit unencrypted/decrypted state into phys_to_dma_direct(),
make the alloc paths return DMA addresses that match the requested buffer
encryption state. Also only call dma_set_decrypted() when
DMA_ATTR_CC_SHARED is actually set.
Tested-by: Jiri Pirko <jiri@nvidia•com>
Tested-by: Michael Kelley <mhklinux@outlook•com>
Tested-by: Mostafa Saleh <smostafa@google•com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel•org>
---
kernel/dma/direct.c | 42 +++++++++++++++++++++++++-----------------
1 file changed, 25 insertions(+), 17 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 9ce4fff6c112..aa3489aa10a0 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -24,11 +24,11 @@
u64 zone_dma_limit __ro_after_init = DMA_BIT_MASK(24);
static inline dma_addr_t phys_to_dma_direct(struct device *dev,
- phys_addr_t phys)
+ phys_addr_t phys, bool unencrypted)
{
- if (force_dma_unencrypted(dev))
+ if (unencrypted)
return phys_to_dma_unencrypted(dev, phys);
- return phys_to_dma(dev, phys);
+ return phys_to_dma_encrypted(dev, phys);
}
static inline struct page *dma_direct_to_page(struct device *dev,
@@ -39,8 +39,9 @@ static inline struct page *dma_direct_to_page(struct device *dev,
u64 dma_direct_get_required_mask(struct device *dev)
{
+ bool require_decrypted = force_dma_unencrypted(dev);
phys_addr_t phys = ((phys_addr_t)max_pfn << PAGE_SHIFT) - 1;
- u64 max_dma = phys_to_dma_direct(dev, phys);
+ u64 max_dma = phys_to_dma_direct(dev, phys, require_decrypted);
return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
}
@@ -69,7 +70,8 @@ static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 *phys_limit)
bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
{
- dma_addr_t dma_addr = phys_to_dma_direct(dev, phys);
+ bool require_decrypted = force_dma_unencrypted(dev);
+ dma_addr_t dma_addr = phys_to_dma_direct(dev, phys, require_decrypted);
if (dma_addr == DMA_MAPPING_ERROR)
return false;
@@ -79,17 +81,18 @@ bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
static int dma_set_decrypted(struct device *dev, void *vaddr, size_t size)
{
- if (!force_dma_unencrypted(dev))
- return 0;
- return set_memory_decrypted((unsigned long)vaddr, PFN_UP(size));
+ int ret;
+
+ ret = set_memory_decrypted((unsigned long)vaddr, PFN_UP(size));
+ if (ret)
+ pr_warn_ratelimited("leaking DMA memory that can't be decrypted\n");
+ return ret;
}
static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size)
{
int ret;
- if (!force_dma_unencrypted(dev))
- return 0;
ret = set_memory_encrypted((unsigned long)vaddr, PFN_UP(size));
if (ret)
pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n");
@@ -169,7 +172,8 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
dma_coherent_ok);
if (!page)
return NULL;
- *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ *dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
+ !!(attrs & DMA_ATTR_CC_SHARED));
return ret;
}
@@ -185,9 +189,11 @@ static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
/* remove any dirty cache lines on the kernel alias */
if (!PageHighMem(page))
arch_dma_prep_coherent(page, size);
-
- /* return the page pointer as the opaque cookie */
- *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ /*
+ * return the page pointer as the opaque cookie.
+ * Never used for unencrypted allocation
+ */
+ *dma_handle = phys_to_dma_encrypted(dev, page_to_phys(page));
return page;
}
@@ -332,7 +338,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
ret = uncached_cpu_addr;
}
- *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ *dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
+ !!(attrs & DMA_ATTR_CC_SHARED));
return ret;
@@ -455,11 +462,12 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
return NULL;
ret = page_address(page);
- if (dma_set_decrypted(dev, ret, size))
+ if ((attrs & DMA_ATTR_CC_SHARED) && dma_set_decrypted(dev, ret, size))
goto out_leak_pages;
setup_page:
memset(ret, 0, size);
- *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ *dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
+ !!(attrs & DMA_ATTR_CC_SHARED));
return page;
out_leak_pages:
return NULL;
--
2.43.0
next prev parent reply other threads:[~2026-06-04 8:42 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 8:39 [PATCH v6 00/20] dma-mapping: Use DMA_ATTR_CC_SHARED through direct, pool and swiotlb paths Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 01/20] s390: Expose protected virtualization through cc_platform_has() Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 02/20] dma-direct: swiotlb: handle swiotlb alloc/free outside __dma_direct_alloc_pages Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 03/20] dma-direct: use DMA_ATTR_CC_SHARED in alloc/free paths Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 04/20] dma-pool: track decrypted atomic pools and select them via attrs Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 05/20] dma: swiotlb: pass mapping attributes by reference Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 06/20] dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 07/20] dma-mapping: make dma_pgprot() " Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 08/20] dma-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 09/20] dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 10/20] dma-direct: set decrypted flag for remapped DMA allocations Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` Aneesh Kumar K.V (Arm) [this message]
2026-06-04 8:39 ` [PATCH v6 12/20] dma-pool: fix page leak in atomic_pool_expand() cleanup Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 13/20] dma-direct: rename ret to cpu_addr in alloc helpers Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 14/20] dma-direct: return struct page from dma_direct_alloc_from_pool() Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 15/20] iommu/dma: Check atomic pool allocation result directly Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 16/20] dma: swiotlb: free dynamic pools from process context Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 17/20] dma: swiotlb: handle set_memory_decrypted() failures Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 18/20] dma: free atomic pool pages by physical address Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 19/20] swiotlb: Preserve allocation virtual address for dynamic pools Aneesh Kumar K.V (Arm)
2026-06-04 8:39 ` [PATCH v6 20/20] swiotlb: remove unused SWIOTLB_FORCE flag Aneesh Kumar K.V (Arm)
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