Re: [PATCH] riscv: Add initial Xen guest support for RISC-V

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Hi Stefano,

On 1/15/25 1:01 AM, Stefano Stabellini wrote:

> +Oleksii
>
> On Tue, 14 Jan 2025, Milan Djokic wrote:
> > From: Slavisa Petrovic <Slavisa.Petrovic@xxxxxxxxx>
> >
> > This patch introduces initial support for running RISC-V as a Xen guest.
> > It provides the necessary infrastructure and stubs for Xen-specific
> > operations. Key changes include:
> >
> > - Modifications to the RISC-V kernel to integrate Xen-specific hypercalls
> >   and interfaces, with function implementations stubbed for future work.
> > - Introduction of Xen-specific headers for RISC-V, including event
> >   handling, hypervisor interaction, and page management. Functions are
> >   defined but not yet implemented.
> > - Stub implementations for memory management, grant tables, and context
> >   switching in the Xen environment, allowing further development and
> >   integration.
> >
> > Signed-off-by: Milan Djokic <Milan.Djokic@xxxxxxxxx>
> > Signed-off-by: Slavisa Petrovic <Slavisa.Petrovic@xxxxxxxxx>
> >       
> Hi Milan, Slavisa,
>
> Thank you very much for your contribution! Which Xen tree are you using
> for development?
>     
They are using [1] and have separate branches on top of latest. So we are in
sync. Also, if you are interested we have created a task/epics for this feature in
[1] so you could also check there some details:
1. https://gitlab.com/groups/xen-project/people/olkur/-/epics/5
2. https://gitlab.com/xen-project/people/olkur/xen/-/issues/12

>  I am asking because RISC-V support in Xen is still in
> the process of being upstreamed, and [1] is the tree that consolidates
> all patches currently on the to-be-upstreamed list.  
>
> While the specific Xen tree you are using is not particularly important
> at this stage, and using [1] is not a requirement, I am asking because
> it is essential to align on the hypervisor ABI, especially regarding any
> details that have not yet been upstreamed. Specifically, is there
> anything in this patch series that relies on features not yet upstream
> in Xen?
>     
There are few features but some things which are Rt-Tk's branch in [1] could go
without waiting for these features to be upstreamed.

Thanks.

~ Oleksii
> [1] https://gitlab.com/xen-project/people/olkur/xen/-/tree/latest?ref_type=heads
>