Re: [XEN PATCH v8 22/22] docs: add Arm FF-A mediator

[Julien Grall <julien@xxxxxxx>]

Hi Jens,

On 13/04/2023 08:14, Jens Wiklander wrote:
> Describes a FF-A version 1.1 [1] mediator to communicate with a Secure
> Partition in secure world.
>
> [1] https://developer.arm.com/documentation/den0077/latest
> Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> ---
>   SUPPORT.md               |  8 ++++++++
>   docs/man/xl.cfg.5.pod.in | 15 +++++++++++++++
>   2 files changed, 23 insertions(+)
>
> diff --git a/SUPPORT.md b/SUPPORT.md
> index aa1940e55f09..1fd746f7f7f2 100644
> --- a/SUPPORT.md
> +++ b/SUPPORT.md
> @@ -818,6 +818,14 @@ that covers the DMA of the device to be passed through.
>   
>   No support for QEMU backends in a 16K or 64K domain.
>   
> +### ARM: Firmware Framework for Arm A-profile (FF-A) Mediator
> +
> +    Status, Arm64: Tech Preview
> +
> +There are still some code paths where a vCPU may hog a pCPU longer than
> +necessary. The FF-A mediator is not yet implemented for Arm32. Part of the
> +FF-A specification is not supported.
NIT: You would suggest to add: "(See the top comment in ...)". So one 
can easily find the limitation.
> +
>   ### ARM: Guest Device Tree support
>   
>       Status: Supported
> diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
> index 10f37990be57..bba99c576b48 100644
> --- a/docs/man/xl.cfg.5.pod.in
> +++ b/docs/man/xl.cfg.5.pod.in
> @@ -1645,6 +1645,21 @@ in OP-TEE.
>   
>   This feature is a B<technology preview>.
>   
> +=item B<ffa>
> +
> +B<Arm only.> Allow a guest to communicate via FF-A with Secure Partitions
> +(SP), default false.
> +
> +Currently is only a small subset of the FF-A specification supported. Just
> +enough to communicate with OP-TEE. In general only direct messaging and
> +sharing memory with one SP. More advanced use cases where memory might be
> +shared or donated to multple SPs are not supported.
Typo: s/multple/multiple/

> +
> +See L<https://developer.arm.com/documentation/den0077/latest> for more
> +informantion about FF-A.
Typo: s/informantion/information/

> +
> +This feature is a B<technology preview>.
> +
>   =back
>   
>   =back
--
Julien Grall