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

[Jens Wiklander <jens.wiklander@xxxxxxxxxx>]

Hi Julien,

On Thu, Apr 13, 2023 at 11:00 PM Julien Grall <julien@xxxxxxx> wrote:
>
> 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.

Good point, I'll fix that.

>
> > +
> >   ### 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/

I'll fix the typos.

Thanks,
Jens

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