From: Allen Pais <firstname.lastname@example.org>
To: Jens Wiklander <email@example.com>
Cc: "Sumit Garg" <firstname.lastname@example.org>,
"Tyler Hicks" <email@example.com>,
Rijo-john.Thomas@amd.com, "Peter Huewe" <firstname.lastname@example.org>,
"Jarkko Sakkinen" <email@example.com>,
"Jason Gunthorpe" <firstname.lastname@example.org>,
"Vikas Gupta" <email@example.com>,
"Thirupathaiah Annapureddy" <firstname.lastname@example.org>,
"Pavel Tatashin" <email@example.com>,
"Rafał Miłecki" <firstname.lastname@example.org>,
"OP-TEE TrustedFirmware" <email@example.com>,
"Linux Kernel Mailing List" <firstname.lastname@example.org>
Subject: Re: [PATCH v3 5/7] tee: Support shm registration without dma-buf backing
Date: Thu, 10 Jun 2021 13:10:35 +0530 [thread overview]
Message-ID: <F2A9E44A-137B-4081-AA82-B84FF4761957@linux.microsoft.com> (raw)
>> AFAIK, its due the the inherent nature of tee_shm_alloc() and
>> tee_shm_register() where tee_shm_alloc() doesn't need to know whether
>> its a kernel or user-space memory since it is the one that allocates
>> whereas tee_shm_register() need to know that since it has to register
>> pre-allocated client memory.
>>> - Why does tee_shm_register() unconditionally use non-contiguous
>>> allocations without ever taking into account whether or not
>>> OPTEE_SMC_SEC_CAP_DYNAMIC_SHM was set? It sounds like that's required
>>> from my reading of https://optee.readthedocs.io/en/latest/architecture/core.html#noncontiguous-shared-buffers.
>> Yeah, but do we have platforms in OP-TEE that don't support dynamic
>> shared memory? I guess it has become the sane default which is a
>> mandatory requirement when it comes to OP-TEE driver in u-boot.
>>> - Why is TEE_SHM_REGISTER implemented at the TEE driver level when it is
>>> specific to OP-TEE? How to better abstract that away?
>> I would like you to go through Section "3.2.4. Shared Memory" in TEE
>> Client API Specification. There are two standard ways for shared
>> memory approach with TEE:
>> 1. A Shared Memory block can either be existing Client Application
>> memory (kernel driver in our case) which is subsequently registered
>> with the TEE Client API (using tee_shm_register() in our case).
>> 2. Or memory which is allocated on behalf of the Client Application
>> using the TEE
>> Client API (using tee_shm_alloc() in our case).
>>> Let me know if you agree with the more minimal approach that I took for
>>> these bug fix series or still feel like tee_shm_register() should be
>>> fixed up so that it is usable. Thanks!
>> From drivers perspective I think the change should be:
> I've just posted "[PATCH 0/7] tee: shared memory updates",
> Where tee_shm_alloc() is replaced by among other functions
> tee_shm_alloc_kernel_buf(). tee_shm_alloc_kernel_buf() takes care of the
> problem with TEE_SHM_DMA_BUF.
Thanks Jens. The series looks fine. Tested too.
next prev parent reply other threads:[~2021-06-10 7:40 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 0:23 [PATCH v3 0/7] tee: Improve support for kexec and kdump Tyler Hicks
2021-06-09 0:23 ` [PATCH v3 1/7] optee: Fix memory leak when failing to register shm pages Tyler Hicks
2021-06-09 0:23 ` [PATCH v3 2/7] optee: Refuse to load the driver under the kdump kernel Tyler Hicks
2021-06-09 0:23 ` [PATCH v3 3/7] optee: fix tee out of memory failure seen during kexec reboot Tyler Hicks
2021-06-09 0:23 ` [PATCH v3 4/7] optee: Clear stale cache entries during initialization Tyler Hicks
2021-06-09 0:23 ` [PATCH v3 5/7] tee: Support shm registration without dma-buf backing Tyler Hicks
2021-06-09 4:29 ` Sumit Garg
2021-06-09 5:46 ` Tyler Hicks
2021-06-09 10:52 ` Sumit Garg
2021-06-09 12:15 ` Jens Wiklander
2021-06-09 13:42 ` Tyler Hicks
2021-06-09 13:51 ` Tyler Hicks
2021-06-10 7:34 ` Jens Wiklander
2021-06-10 21:00 ` Tyler Hicks
2021-06-10 7:49 ` Jens Wiklander
2021-06-10 21:05 ` Tyler Hicks
2021-06-10 7:40 ` Allen Pais [this message]
2021-06-10 7:18 ` Jens Wiklander
2021-06-10 12:14 ` Sumit Garg
2021-06-09 0:23 ` [PATCH v3 6/7] tpm_ftpm_tee: Free and unregister dynamic shared memory during kexec Tyler Hicks
2021-06-09 0:23 ` [PATCH v3 7/7] firmware: tee_bnxt: Release shm, session, and context " Tyler Hicks
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