On Thu, May 29, 2025 at 11:40 PM Teddy Astie <teddy.as...@vates.tech> wrote:
> Hello Christopher, > Hi Teddy, thanks for the review. > > Le 28/05/2025 à 23:13, Christopher Clark a écrit : > > Adds approachable documentation describing system components and > > introduces the support statement for feature status. > ... > > +# Overview > > + > > +Argo is a lightweight data transport for communication between virtual > > +machines, with a simple hypervisor interface that is accessible for > > +building embedded systems and designed to work with familiar primitives > > +within guest OS kernels. It supports policy control over communication > > +and isolation between VMs. > > + > > +# User details > > + > > +Argo is present in Xen, included since Xen 4.12. A Linux device driver > > +and userspace library are available and Argo is regularly tested in the > > +Xen Continuous Integration system. > > + > > Not really related to the documentation itself, but it would be > preferable to have the Linux driver upstreamed such as this sentence > sounds more as "it is supported" rather than "it's possible to make it > work". > I agree and I can work on a better description for the next posting. > > It would also make Argo easier to integrate in Xen-based projects. > Yes (for systems with Linux). > > > +To configure a Xen system to enable Argo: > > + > > +* ensure that Argo is enabled in the hypervisor with KConfig option > > + > > +* enable Argo on the Xen hypervisor command line > > + > > +* load the Argo guest kernel device driver > > + > > +* ensure that the Argo guest libraries are installed > > + > > +The guest userspace libraries support software designed for Argo > > +interfaces and also enables software designed for networks to > > +communicate between VMs by Argo. This allows platform software to be > > +plumbed easily between virtual machines, without requiring networking > > +and with system policy controls over this communication. > > + > > +# Technical details > > + > > +## Argo components > > + > > +* Xen: Argo in the hypervisor provides communication between virtual > > + machines. > > + > > +* Guest kernel: driver provides interfaces for data transport for use > > + within the kernel, and implements familiar abstractions for > > + networking software. > > + > > +* Guest libraries: provide application-level support for interdomain > > + communication. > > + > > That sounds a bit confusing to me, the guest kernel provides familiar > abstractions for networking software (I hear through that something like > sockets), yet we still have guest libraries for application-level support. > > I think the guest libraries provide a shim for some of the argo-specific > aspects (like ioctls and sockaddr_argo related bits); while the > interface is more unix-oriented with regular sockets operations > (sendmsg, ...). > OK, I wasn't sure what level of detail would be wanted for this so it's useful to know, thanks. > > > +## Argo implementation within Xen > > + > > +See the public Xen headers for the primary interface documentation. > > + > > There is the design document in docs/designs/argo.pandoc that explains > the inner design inside Xen. I think the public headers are more for > guest consumption. > OK, I'll add reference to the design document. > > As this document also targets guest developers, it would be great to > have some guidance (e.g a docs document) on how a guest should implement > argo support. > Thanks, I appreciate the enthusiasm for it to be written! best, Christopher
