Re: [PATCH V5 1/3] xen/arm: Introduce gpaddr_bits field to struct xen_arch_domainconfig

[Oleksandr <olekstysh@xxxxxxxxx>]

On 09.10.21 01:14, Stefano Stabellini wrote:

Hi Stefano

> On Fri, 8 Oct 2021, Oleksandr wrote:
> > On 08.10.21 15:36, Jan Beulich wrote:
> > > On 08.10.2021 12:25, Oleksandr wrote:
> > > > Just a quick question. What do you think can XEN_DOMCTL_getdomaininfo be
> > > > reused to retrieve gpaddr_bits? I don't see why not at the moment, but
> > > > maybe there are some implications/concerns which are invisible to me.
> > > >
> > > > I see that arch_get_domain_info() is present, so the field will be
> > > > common, and each arch will write a value it considers
> > > > appropriate. This could be a good compromise to not add an extra domctl
> > > > and to not alter domain_create.
> > > Technically I think it could be reused. What I'm less certain of is
> > > whether the specific piece of information is a good fit there.
> > ok, thank you for your answer.
> >
> > I am also not 100% sure whether it is a *good* fit there, but I cannot say it
> > is not fit at all for being there. I might mistake, but it is almost the same
> > piece of information describing the whole domain as other existing fields in
> > that structure.
>  From a domctl point of view, it looks like XEN_DOMCTL_getdomaininfo
> could be a decent fit. Looking at the data structure, the arch specific
> member of struct xen_domctl_getdomaininfo is:
>
>    struct xen_arch_domainconfig arch_config;
>
> which is actually the very same struct used in struct
> xen_domctl_createdomain for XEN_DOMCTL_createdomain, but somehow it
> doesn't get populated by neither the x86 nor the ARM version of
> arch_get_domain_info?
>
>
> In any case, I think we could make use of XEN_DOMCTL_getdomaininfo for
> this. In that case, I would add a new common field to struct
> xen_domctl_getdomaininfo after cpupool and above arch_config.
>
> Then we can set the field from arch_get_domain_info.
Yes, this is what I had in mind, thank you.


--
Regards,

Oleksandr Tyshchenko