Re: [PATCH v9 3/4] SUPPORT.md: Document PSCI SYSTEM_SUSPEND support for guests

[Mykola Kvach <xakep.amatop@xxxxxxxxx>]

Hi Julien,

On Sun, Aug 24, 2025 at 12:31 AM Julien Grall <julien@xxxxxxx> wrote:
>
> Hi Mykola,
>
> On 18/08/2025 09:49, Mykola Kvach wrote:
> > From: Mykola Kvach <mykola_kvach@xxxxxxxx>
> >
> > Add a new entry under the "Virtual Hardware, QEMU" section documenting
> > support for the optional PSCI SYSTEM_SUSPEND function exposed to guests.
> >
> > This function is available via the virtual PSCI (vPSCI) interface and
> > allows guest domains (domUs) to initiate system suspend operations.
> >
> > The feature is currently marked as Experimental.
> >
> > Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
> > ---
> > Changes in v6:
> > - Dropped the generic guest PSCI support entry (merged in a separate patch)
> > - This patch now documents only the SYSTEM_SUSPEND optional function
> > - Reworded commit message to match the final form after rebase
> >
> > Changes in v5:
> > - Dropped ARM/PSCI entry: this refers to internal use of PSCI SMC calls,
> >    which is not relevant for SUPPORT.md
> > - Added a dedicated entry for PSCI SYSTEM_SUSPEND instead of generic guest
> >    PSCI info; guest PSCI support was documented in a separate patch
> > ---
> >   SUPPORT.md | 5 +++--
> >   1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/SUPPORT.md b/SUPPORT.md
> > index 6a82a92189..b5ab049b52 100644
> > --- a/SUPPORT.md
> > +++ b/SUPPORT.md
> > @@ -962,8 +962,9 @@ Emulated PSCI interface exposed to guests. We support 
> > all mandatory
> >   functions of PSCI 1.1. See below for the list of optional PSCI call
> >   implemented and their status.
> >
> > -   Status, Mandatory: Supported
> > -   Status, MIGRATE_INFO_TYPE: Supported
> > +    Status, Mandatory: Supported
> > +    Status, MIGRATE_INFO_TYPE: Supported
> > +    Status, SYSTEM_SUSPEND: Experimental
>
> Experimental implies the feature is not complete. But it is unclear to
> me what is missing (or I probably forgotten). Can this be clarified in
> the commit message?
>
> If there is nothing, then I think it can be a tech preview.

I initially thought that we would need to add a "xl suspend" command
in order to allow suspending another domain via the control/hardware
domain. However, after your question I reconsidered it and realized
that this functionality is not directly related to vPSCI, but rather
to Xen system suspend support.

So, I will change it to "Tech Preview" as you proposed. Thank you!

>
> Cheers,
>
> --
> Julien Grall
>

Best regards,
Mykola