Re: [RFC PATCH v2 2/4] KVM: arm64: Add PSCI SYSTEM_OFF2 function for hibernation

[David Woodhouse]

On Mon, 2024-03-18 at 17:29 +0000, Marc Zyngier wrote:
> 
> Again, I really oppose this way of doing things. We already have an
> infrastructure for selecting PSCI levels. You may not like it, but it
> exists, and I'm not going entertain supporting yet another bike-shed
> model. Adding an orthogonal cap for a feature that is specific to a
> new PSCI version is just awful.

Huh? This isn't a "new bike-shed model". This is a straight copy of
what we *already* have for SYSTEM_RESET2.

If I were bike-shedding, I wouldn't do separate caps for them; I'd have
done it as a *bitmask* of the optional PSCI calls that should be
enabled.

The *mandatory* ones should obviously come from the PSCI version alone,
but I can't see how that makes sense for the optional ones...

> Please make PSCI 1.3 the only version of PSCI supporting suspend in a
> non-optional way, and be done with it.

SYSTEM_OFF2 is an *optional* feature in PSCI v1.3. As are
CLEAR_INV_MEMREGION and CLEAR_INV_MEMREGION_ATTRIBUTES.

Are you suggesting that enabling v1.3 should automatically enable *all*
of the optional features that were defined in that version (and
previous versions) of the spec?

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