On Mon, 18 Mar 2024 17:54:06 +0000, David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote: > > [1 <text/plain; UTF-8 (quoted-printable)>] > 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. There is no KVM capability for SYSTEM_RESET2. It is directly advertised to the guest when PSCI 1.1 is supported. > 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... The guest is in a position to probe for what is supported or not with the PSCI_FEATURES call. Why would you add anything else? > > > 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? No. We have everything we need to incrementally *add* features. So you can perfectly implement PSCI 1.3 with only SYSTEM_OFF2, and only later on add the rest, if ever. M. -- Without deviation from the norm, progress is not possible.
