Re: [PATCH v3 2/4] xen/arm: Alloc XenStore page for Dom0less DomUs from hypervisor

[Jürgen Groß <jgross@xxxxxxxx>]

On 25.05.24 01:19, Stefano Stabellini wrote:
> On Fri, 24 May 2024, Jürgen Groß wrote:
> > On 24.05.24 15:58, Julien Grall wrote:
> > > Hi Henry,
> > >
> > > + Juergen as the Xenstore maintainers. I'd like his opinion on the approach.
> > > The documentation of the new logic is in:
> > >
> > > https://lore.kernel.org/xen-devel/20240517032156.1490515-5-xin.wang2@xxxxxxx/
> > >
> > > FWIW I am happy in principle with the logic (this is what we discussed on
> > > the call last week). Some comments below.
> > I'm not against this logic, but I'm wondering why it needs to be so
> > complicated.
> Actually the reason I like it is that in my view, this is the simplest
> approach. You allocate a domain, you also allocate the xenstore page
> together with it. Initially the xenstore connection has an
> "uninitialized" state, as it should be. That's it. At some point, when
> xenstored is ready, the state changes to CONNECTED.
>
>
> > Can't the domU itself allocate the Xenstore page from its RAM pages,
> > write the PFN into the Xenstore grant tab entry, and then make it
> > public via setting HVM_PARAM_STORE_PFN?
> This is not simpler in my view
Okay, fine with me. I had the impression that violating the 1:1 mapping
of the domain would add complexity, but if you are fine with that I don't
mind your approach.


Juergen