Re: [PATCH] optee: enable OPTEE_SMC_SEC_CAP_MEMREF_NULL capability

[Julien Grall <julien@xxxxxxx>]

Hi Volodymyr,

On 07/05/2021 02:39, Volodymyr Babchuk wrote:
> OP-TEE mediator already have support for NULL memory references. It
> was added in patch 0dbed3ad336 ("optee: allow plain TMEM buffers with
> NULL address"). But it does not propagate
> OPTEE_SMC_SEC_CAP_MEMREF_NULL capability flag to a guest, so well
> behaving guest can't use this feature.
>
> Note: linux optee driver honors this capability flag when handling
> buffers from userspace clients, but ignores it when working with
> internal calls. For instance, __optee_enumerate_devices() function
> uses NULL argument to get buffer size hint from OP-TEE. This was the
> reason, why "optee: allow plain TMEM buffers with NULL address" was
> introduced in the first place.
>
> This patch adds the mentioned capability to list of known
> capabilities. From Linux point of view it means that userspace clients
> can use this feature, which is confirmed by OP-TEE test suite:
>
> * regression_1025 Test memref NULL and/or 0 bytes size
> o regression_1025.1 Invalid NULL buffer memref registration
>    regression_1025.1 OK
> o regression_1025.2 Input/Output MEMREF Buffer NULL - Size 0 bytes
>    regression_1025.2 OK
> o regression_1025.3 Input MEMREF Buffer NULL - Size non 0 bytes
>    regression_1025.3 OK
> o regression_1025.4 Input MEMREF Buffer NULL over PTA invocation
>    regression_1025.4 OK
>    regression_1025 OK
>
> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

And committed.

Cheers,

--
Julien Grall