Re: [PATCH v5 3/4] SUPPORT.md: Add entry for guest PSCI SYSTEM_SUSPEND support

[Julien Grall <julien@xxxxxxx>]

Hi Mykola,

On 27/06/2025 11:51, Mykola Kvach wrote:
> From: Mykola Kvach <mykola_kvach@xxxxxxxx>
>
> Document support for the optional PSCI SYSTEM_SUSPEND function, exposed
> via the virtual PSCI (vPSCI) interface to guests.
>
> This allows non-hardware domain guests (domUs) to initiate system suspend
> operations via PSCI calls. The feature is currently marked as Experimental.
>
> Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
> ---
> 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 | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/SUPPORT.md b/SUPPORT.md
> index f0b5718e84..659b9c3052 100644
> --- a/SUPPORT.md
> +++ b/SUPPORT.md
> @@ -956,6 +956,13 @@ by hwdom. Some platforms use SCMI for access to 
> system-level resources.
>   
>       Status: Supported
>   
> +### ARM: Guest PSCI SYSTEM_SUSPEND support
You are already adding a Guest PSCI section in [1]. I would rather not 
another section just for SYSTEM_SUSPEND. This would make more difficult 
to know what part of PSCI is supported.
Instead, I would tweak the merge the two patches and tweak the wording 
to have something like:
  Status, Mandatory: Supported
  Status, MIGRATE_INFO_TYPE: Supported
  Status, SYSTEM_SUSPEND: Experimental

Also, I will comment directly here:

> Emulated PSCI interface exposed to guests. Supports all mandatory 
functions from PSCI versions 0.2 and 1.0, as well as the optional 
MIGRATE_INFO_TYPE
Xen is supporting PSCI 1.1 which is backwards compatible up to 0.2. But 
effectively, we don't expose 0.2 nor 1.0.
So I would reword to:

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.
Cheers,

[1] 
https://lore.kernel.org/all/20250627053313.2233826-1-xakep.amatop@xxxxxxxxx/
--
Julien Grall