On Thu, 3 Aug 2023, Stefano Stabellini wrote: > On Thu, 3 Aug 2023, Daniel P. Smith wrote: > > > Also, what is the plan for the existing dom0less dt properties? > > > Will they need to be moved to new /hypervisor node or we will have to > > > parse > > > both /chosen and /hypervisor nodes? > > > > In the proposal I sent to xen-devel in response to Luca's RFC for rebranding > > dom0less features under hyperlaunch, that is the purpose of this commit. Get > > this document up to date with what was done in v1 along with what we are > > planning/working on for hyperlaunch. One could think of this as effectively > > the API to the capabilities hyperlaunch will provide. Not just how to > > construct a domain, but what kinds of domains can be constructed by > > hyperlaunch. Step one of the proposal is to publish a patch upon which we > > all > > can iterate over and get to an agreement on a suitable interface for all. > > The > > next step would be the introduction of hyperlaunch dom0less compatibility > > mode, that would see the moving of the parsing logic for the existing > > dom0less > > nodes under /xen/common/domain-builder. It would continue to exist there > > even > > after hyperlaunch proper is merged and can remain there for backward > > compatibility until there is a decision to retire the compatibility > > interface. > > I like this plan. The two interfaces are so similar that it is basically > one interface with a couple of tiny differences. > > So I expect we would move the existing dom0less parsing code to common/, > add a couple of extensions (such as parsing /hypervisor in addition to > /chosen) and use it as it. > > Later on, after a few years of using /hypervisor instead of /chosen, if > nobody is using /chosen anymore, we could retire /chosen completely. But > this is just one DT node/property that gets retired (there are a couple > of others). I don't imagine we'll have a full new implementation of the > DT parsing logic that supersedes the existing implementation of it > (especially considering the difficulty of maintaining 2 different parsing > logics in the hypervisor for similar interfaces). > > Same thing for the DT interface documentation. I don't think we need two > DT interface docs? We could start with the existing dom0less interface > (docs/misc/arm/device-tree/booting.txt), and move it somewhere common > like docs/misc/device-tree. > > Then add any changes or extensions required by other architecture, such > as x86 and RISC-V. > > For sure for x86 we need "module-index". I don't know if anything else > is must-have to get it to work on x86 but if there is, we should add > those too.
For clarity, I think we should definitely have docs/design/launch/hyperlaunch.rst, and maybe we should also have hyperlaunch-devicetree.rst as an overview description and user guide. That's useful. But in terms of official device tree bindings interface description (basically what in Linux would go under Documentation/devicetree/bindings/), I think it would be best to only have a single document. The current one is docs/misc/arm/device-tree/booting.txt.
