From: Jason Gunthorpe <jgg@ziepe.ca>
To: Brian Starkey <brian.starkey@arm.com>
Cc: Jiri Pirko <jiri@resnulli.us>,
dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
iommu@lists.linux.dev, linux-media@vger.kernel.org,
sumit.semwal@linaro.org, benjamin.gaignard@collabora.com,
jstultz@google.com, tjmercier@google.com,
christian.koenig@amd.com, m.szyprowski@samsung.com,
robin.murphy@arm.com, leon@kernel.org, sean.anderson@linux.dev,
ptesarik@suse.com, catalin.marinas@arm.com,
aneesh.kumar@kernel.org, suzuki.poulose@arm.com,
steven.price@arm.com, thomas.lendacky@amd.com,
john.allen@amd.com, ashish.kalra@amd.com,
suravee.suthikulpanit@amd.com, linux-coco@lists.linux.dev,
nd@arm.com
Subject: Re: [PATCH v5 0/2] dma-buf: heaps: system: add an option to allocate explicitly shared/decrypted memory
Date: Thu, 2 Apr 2026 09:02:54 -0300 [thread overview]
Message-ID: <20260402120254.GB2551565@ziepe.ca> (raw)
In-Reply-To: <4s75rtsmdfrze4rscbqzyrjyrko7n6sehe7agrngqag2cna5bz@eflmf4kwjocj>
On Thu, Apr 02, 2026 at 10:52:34AM +0100, Brian Starkey wrote:
> I'm not clear why the heap depends on !CONFIG_HIGHMEM, but I also
> don't know anything about SEV/TDX.
It is because the CC apis, set_memory_decrypted()/etc are slightly
mis-designed. They take in a vaddr to represent the address instead of
a phys_addr_t or a page *
This means the user has to use page_address() and then the whole thing
is incompatible with highmem.
Which is fine, highmem and CC are never turned on together.
Jason
next prev parent reply other threads:[~2026-04-02 12:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20260325192400eucas1p2ae38ff4c2b3ab35a7047cfd680d9fda3@eucas1p2.samsung.com>
2026-03-25 19:23 ` [PATCH v5 0/2] dma-buf: heaps: system: add an option to allocate explicitly shared/decrypted memory Jiri Pirko
2026-03-25 19:23 ` [PATCH v5 1/2] dma-mapping: introduce DMA_ATTR_CC_SHARED for shared memory Jiri Pirko
2026-03-31 15:08 ` Jason Gunthorpe
2026-03-25 19:23 ` [PATCH v5 2/2] dma-buf: heaps: system: add system_cc_shared heap for explicitly " Jiri Pirko
2026-03-27 19:43 ` T.J. Mercier
2026-03-31 15:08 ` Jason Gunthorpe
2026-04-02 12:23 ` Maxime Ripard
2026-04-02 12:56 ` Jiri Pirko
2026-03-27 9:38 ` [PATCH v5 0/2] dma-buf: heaps: system: add an option to allocate explicitly shared/decrypted memory Marek Szyprowski
2026-03-27 12:10 ` Jason Gunthorpe
2026-03-27 19:43 ` T.J. Mercier
2026-04-02 4:41 ` Sumit Semwal
2026-04-02 5:35 ` Marek Szyprowski
2026-04-02 9:52 ` Brian Starkey
2026-04-02 12:02 ` Jason Gunthorpe [this message]
2026-04-02 12:58 ` Jiri Pirko
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