From: Jiri Pirko <jiri@resnulli.us>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Stultz <jstultz@google.com>,
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,
Brian.Starkey@arm.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
Subject: Re: [PATCH 4/5] dma-buf: heaps: allow heap to specify valid heap flags
Date: Tue, 10 Feb 2026 15:49:02 +0100 [thread overview]
Message-ID: <y7gvezflidmma7odnut2rmlecsbxahrcwpmoevfnhzjveusuwj@6qxqogin45j3> (raw)
In-Reply-To: <20260210124357.GD943673@ziepe.ca>
Tue, Feb 10, 2026 at 01:43:57PM +0100, jgg@ziepe.ca wrote:
>On Tue, Feb 10, 2026 at 10:14:08AM +0100, Jiri Pirko wrote:
>
>> >I'd advocate that the right design is for userspace to positively
>> >signal via this flag that it wants/accepts shared memory and without
>> >the flag shared memory should never be returned.
>>
>> We can have the same behaviour with the separate heap, can't we?
>> Userpace positively signals it wants/accepts the shared memory by
>> choosing "system_cc_decrypted" heap name.
>
>So what do the other heap names do? Always private? Do you ever get
>heaps that are unknowably private or shared (eg MMIO backed?)
If I understand the code correctly, you may get something like this:
$ ls /dev/dma_heap/
default_cma_region
protected,secure-video
protected,secure-video-record
protected,trusted-ui
system
The "protected*" ones are created by tee. I believe they handle
memory that is inaccesible to CPU.
next prev parent reply other threads:[~2026-02-10 14:49 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-09 15:38 [PATCH 0/5] dma-buf: heaps: system: add an option to allocate explicitly decrypted memory Jiri Pirko
2026-02-09 15:38 ` [PATCH 1/5] dma-mapping: avoid random addr value print out on error path Jiri Pirko
2026-02-11 6:59 ` Claude review: " Claude Code Review Bot
2026-02-12 11:03 ` [PATCH 1/5] " Marek Szyprowski
2026-02-12 12:52 ` Jiri Pirko
2026-02-09 15:38 ` [PATCH 2/5] dma-mapping: introduce DMA_ATTR_CC_DECRYPTED for pre-decrypted memory Jiri Pirko
2026-02-11 6:59 ` Claude review: " Claude Code Review Bot
2026-02-09 15:38 ` [PATCH 3/5] dma-buf: heaps: use designated initializer for exp_info Jiri Pirko
2026-02-11 6:59 ` Claude review: " Claude Code Review Bot
2026-02-09 15:38 ` [PATCH 4/5] dma-buf: heaps: allow heap to specify valid heap flags Jiri Pirko
2026-02-09 20:08 ` John Stultz
2026-02-10 0:29 ` Jason Gunthorpe
2026-02-10 9:14 ` Jiri Pirko
2026-02-10 12:43 ` Jason Gunthorpe
2026-02-10 14:49 ` Jiri Pirko [this message]
2026-02-10 14:54 ` Jason Gunthorpe
2026-02-10 9:05 ` Jiri Pirko
2026-02-10 12:48 ` Leon Romanovsky
2026-02-10 20:05 ` John Stultz
2026-02-11 6:59 ` Claude review: " Claude Code Review Bot
2026-02-09 15:38 ` [PATCH 5/5] dma-buf: heaps: system: add an option to allocate explicitly decrypted memory Jiri Pirko
2026-02-10 12:02 ` kernel test robot
2026-02-10 18:03 ` kernel test robot
2026-02-11 6:59 ` Claude review: " Claude Code Review Bot
2026-02-11 6:59 ` Claude Code Review Bot
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