From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jiri Pirko <jiri@resnulli.us>
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 v2 2/2] dma-buf: heaps: system: add system_cc_decrypted heap for explicitly decrypted memory
Date: Tue, 24 Feb 2026 15:04:45 -0400 [thread overview]
Message-ID: <aZ32TUEy9CB6rs2d@ziepe.ca> (raw)
In-Reply-To: <5z6d2etfr24oscoxhk3samf2bbhtcz6hymf65cow76omagsplf@6gdaev2perkk>
On Tue, Feb 24, 2026 at 09:32:01AM +0100, Jiri Pirko wrote:
> >Should there be some global list of leaked decrypted pages such that
> >the mm subsystem could try again later to recover these?
>
> swiotlb does the same non-recovery leakage. I belive is it not worth
> implementing this at this time,
Yeah, I agree
Looking at the callers the purpose of the return code is to trigger
the memory leak because there is no way to recover from this. We have
no idea when in future the hypervisor might permit the operation and
we have no way to keep track of the memory until it does.
It is not a great API design at all, it only makes sense from the
hypervisor perspective where it can run out of memory trying to do
these changes..
Jason
prev parent reply other threads:[~2026-02-24 19:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-23 9:51 [PATCH v2 0/2] dma-buf: heaps: system: add an option to allocate explicitly decrypted memory Jiri Pirko
2026-02-23 9:51 ` [PATCH v2 1/2] dma-mapping: introduce DMA_ATTR_CC_DECRYPTED for pre-decrypted memory Jiri Pirko
2026-02-23 9:51 ` [PATCH v2 2/2] dma-buf: heaps: system: add system_cc_decrypted heap for explicitly decrypted memory Jiri Pirko
2026-02-23 18:33 ` John Stultz
2026-02-24 8:32 ` Jiri Pirko
2026-02-24 19:04 ` Jason Gunthorpe [this message]
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