From: Jason Gunthorpe <jgg@ziepe.ca>
To: Michael Kelley <mhklinux@outlook.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-coco@lists.linux.dev" <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" <linuxppc-dev@lists.ozlabs.org>,
"linux-s390@vger.kernel.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" <x86@kernel.org>, Jiri Pirko <jiri@nvidia.com>
Subject: Re: [PATCH v5 05/20] dma-pool: track decrypted atomic pools and select them via attrs
Date: Tue, 2 Jun 2026 21:54:54 -0300 [thread overview]
Message-ID: <20260603005454.GM2487554@ziepe.ca> (raw)
In-Reply-To: <SN6PR02MB4157D9955A93244014AB7978D4122@SN6PR02MB4157.namprd02.prod.outlook.com>
On Tue, Jun 02, 2026 at 02:24:40PM +0000, Michael Kelley wrote:
> Except that in a normal VM, the "unencrypted" pool attribute does *not*
> describe the state of the memory itself. In a normal VM, the memory is
> unencrypted, but the "unencrypted" pool attribute is false. That
> contradiction is the essence of my concern.
I would argue no..
When CC is enabled the default state of memory in a Linux environment
is "encrypted". You have to take a special action to "decrypt" it.
Thus the default state of memory in a non-CC environment is also
paradoxically "encrypted" too. "decryption" is impossible.
Therefore the "unencrypted" state is a special state that only memory
inside a CC VM can have. A normal VM can never have "unencrypted"
memory at all, so having it be false in the pool is accurate as far as
the APIs go.
un-encrypted = true means "the memory in this pool was transformed with
set_memory_decrypted()" - which is impossible on a normal VM.
Jason
next prev parent reply other threads:[~2026-06-03 0:55 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-22 4:27 [PATCH v5 00/20] dma-mapping: Use DMA_ATTR_CC_SHARED through direct, pool and swiotlb paths Aneesh Kumar K.V (Arm)
2026-05-22 4:27 ` [PATCH v5 01/20] [DO NOT MERGE] arm64/coco: Add pKVM as a CC platform Aneesh Kumar K.V (Arm)
2026-05-22 4:27 ` [PATCH v5 02/20] [DO NOT MERGE] s390: Expose protected virtualization through cc_platform_has() Aneesh Kumar K.V (Arm)
2026-05-22 15:35 ` JAEHOON KIM
2026-05-22 4:27 ` [PATCH v5 03/20] dma-direct: swiotlb: handle swiotlb alloc/free outside __dma_direct_alloc_pages Aneesh Kumar K.V (Arm)
2026-05-22 4:27 ` [PATCH v5 04/20] dma-direct: use DMA_ATTR_CC_SHARED in alloc/free paths Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 05/20] dma-pool: track decrypted atomic pools and select them via attrs Aneesh Kumar K.V (Arm)
2026-05-28 18:29 ` Michael Kelley
2026-06-02 6:05 ` Aneesh Kumar K.V
2026-06-02 14:24 ` Michael Kelley
2026-06-03 0:54 ` Jason Gunthorpe [this message]
2026-06-04 14:05 ` Michael Kelley
2026-06-04 14:30 ` Jason Gunthorpe
2026-06-04 14:57 ` Aneesh Kumar K.V
2026-06-04 16:18 ` Michael Kelley
2026-06-04 18:24 ` Jason Gunthorpe
2026-06-08 10:44 ` Marek Szyprowski
2026-05-22 4:28 ` [PATCH v5 06/20] dma: swiotlb: pass mapping attributes by reference Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 07/20] dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 08/20] dma-mapping: make dma_pgprot() " Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 09/20] dma-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 10/20] dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-05-26 2:56 ` Michael Kelley
2026-05-26 15:39 ` Jason Gunthorpe
2026-06-02 6:10 ` Aneesh Kumar K.V
2026-05-22 4:28 ` [PATCH v5 11/20] dma-direct: set decrypted flag for remapped DMA allocations Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 12/20] dma-direct: select DMA address encoding from DMA_ATTR_CC_SHARED Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 13/20] dma-pool: fix page leak in atomic_pool_expand() cleanup Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 14/20] dma-direct: rename ret to cpu_addr in alloc helpers Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 15/20] dma-direct: return struct page from dma_direct_alloc_from_pool() Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 16/20] iommu/dma: Check atomic pool allocation result directly Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 17/20] dma: swiotlb: free dynamic pools from process context Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 18/20] dma: swiotlb: handle set_memory_decrypted() failures Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 19/20] dma: free atomic pool pages by physical address Aneesh Kumar K.V (Arm)
2026-05-22 4:28 ` [PATCH v5 20/20] swiotlb: Preserve allocation virtual address for dynamic pools Aneesh Kumar K.V (Arm)
2026-05-26 4:30 ` [PATCH v5 00/20] dma-mapping: Use DMA_ATTR_CC_SHARED through direct, pool and swiotlb paths Michael Kelley
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260603005454.GM2487554@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=Suzuki.Poulose@arm.com \
--cc=agordeev@linux.ibm.com \
--cc=aik@amd.com \
--cc=aneesh.kumar@kernel.org \
--cc=borntraeger@linux.ibm.com \
--cc=catalin.marinas@arm.com \
--cc=chleroy@kernel.org \
--cc=dan.j.williams@intel.com \
--cc=gerald.schaefer@linux.ibm.com \
--cc=gor@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=iommu@lists.linux.dev \
--cc=jiri@nvidia.com \
--cc=jiri@resnulli.us \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-coco@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=m.szyprowski@samsung.com \
--cc=maddy@linux.ibm.com \
--cc=maz@kernel.org \
--cc=mhklinux@outlook.com \
--cc=mpe@ellerman.id.au \
--cc=npiggin@gmail.com \
--cc=ptesarik@suse.com \
--cc=robin.murphy@arm.com \
--cc=smostafa@google.com \
--cc=steven.price@arm.com \
--cc=svens@linux.ibm.com \
--cc=will@kernel.org \
--cc=x86@kernel.org \
--cc=yilun.xu@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox