From: Jason Gunthorpe <jgg@ziepe.ca>
To: Leon Romanovsky <leon@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev,
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>,
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, stable@vger.kernel.org,
Michael Kelley <mhklinux@outlook.com>
Subject: Re: [PATCH v8 01/23] dma-direct: return struct page from dma_direct_alloc_from_pool()
Date: Mon, 27 Jul 2026 01:23:57 -0300 [thread overview]
Message-ID: <ambdXXcfgK+cxqxa@ziepe.ca> (raw)
In-Reply-To: <20260726081753.GD12003@unreal>
On Sun, Jul 26, 2026 at 11:17:53AM +0300, Leon Romanovsky wrote:
> Currently, the phys type universally describes memory and can be
> reliably translated into any required representation. It is the most
> fundamental type we have.
You cannot go from phys to page reliably unless you make assumptions
about the phys, that's the whole issue here. If the callchain expects
and intends to use a page it should really stay in a page and not take
a side trip to phys.
I agree it would help to have some helpers that were more phys based
for the callchains that want that since we are mixing two fairly
different activities in these functions..
But making phys the only output out of the pool isn't going to be an
improvement.
BTW how does a struct page even work for decrypted memory? You can't
actually use it that way right? If you try to access it then you'll
get the wrong IPA and it should explode?
Maybe we should be blocking the struct page path entirely for CC
shared?
Jason
next prev parent reply other threads:[~2026-07-27 4:24 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-17 18:04 [PATCH v8 00/23] dma-mapping: Track shared DMA state through direct, pool and swiotlb paths Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 01/23] dma-direct: return struct page from dma_direct_alloc_from_pool() Aneesh Kumar K.V (Arm)
2026-07-21 11:54 ` Leon Romanovsky
2026-07-21 14:20 ` Aneesh Kumar K.V
2026-07-21 14:29 ` Leon Romanovsky
2026-07-21 15:10 ` Aneesh Kumar K.V
2026-07-21 15:33 ` Leon Romanovsky
2026-07-22 19:59 ` Jason Gunthorpe
2026-07-23 7:57 ` Leon Romanovsky
2026-07-25 14:34 ` Jason Gunthorpe
2026-07-26 8:17 ` Leon Romanovsky
2026-07-27 4:23 ` Jason Gunthorpe [this message]
2026-07-17 18:04 ` [PATCH v8 02/23] dma-pool: fix page leak in atomic_pool_expand() cleanup Aneesh Kumar K.V (Arm)
2026-07-21 12:31 ` Leon Romanovsky
2026-07-21 14:41 ` Aneesh Kumar K.V
2026-07-21 15:34 ` Leon Romanovsky
2026-07-17 18:04 ` [PATCH v8 03/23] iommu/dma: Check atomic pool allocation result directly Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 04/23] dma: free atomic pool pages by physical address Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 05/23] swiotlb: Preserve allocation virtual address for dynamic pools Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 06/23] s390: Expose protected virtualization through cc_platform_has() Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 07/23] dma-direct: swiotlb: handle swiotlb alloc/free outside __dma_direct_alloc_pages Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 08/23] coco: arm64: s390: powerpc: Mark secure guests with CC_ATTR_GUEST_MEM_ENCRYPT Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 09/23] dma-mapping: Add internal shared allocation attribute Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 10/23] dma-direct: use __DMA_ATTR_ALLOC_CC_SHARED in alloc/free paths Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 11/23] dma-pool: track decrypted atomic pools and select them via attrs Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 12/23] dma: swiotlb: pass mapping attributes by reference Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 13/23] dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 14/23] dma-mapping: make dma_pgprot() honor __DMA_ATTR_ALLOC_CC_SHARED Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 15/23] dma-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 16/23] dma-direct: Move dma_direct_map_phys() to dma/direct.c Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 17/23] dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 18/23] dma-direct: set decrypted flag for remapped DMA allocations Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 19/23] dma-direct: select DMA address encoding from __DMA_ATTR_ALLOC_CC_SHARED Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 20/23] dma-direct: rename ret to cpu_addr in alloc helpers Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 21/23] dma: swiotlb: free dynamic pools from process context Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 22/23] dma: swiotlb: handle set_memory_decrypted() failures Aneesh Kumar K.V (Arm)
2026-07-17 18:04 ` [PATCH v8 23/23] swiotlb: remove unused SWIOTLB_FORCE flag Aneesh Kumar K.V (Arm)
2026-07-21 12:40 ` [PATCH v8 00/23] dma-mapping: Track shared DMA state through direct, pool and swiotlb paths Leon Romanovsky
2026-07-22 19:57 ` Jason Gunthorpe
2026-07-23 7:51 ` Leon Romanovsky
2026-07-25 14:32 ` Jason Gunthorpe
2026-07-25 7:09 ` Aneesh Kumar K.V
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