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

[Jan Beulich <jbeulich@suse.com>]

On 06.10.2021 13:22, Oleksandr Tyshchenko wrote:
> Changes V4 -> V5:
>    - update patch subject and description
>    - drop Michal's R-b
>    - pass gpaddr_bits via createdomain domctl
>      (struct xen_arch_domainconfig)

I'm afraid I can't bring this in line with ...

> --- a/xen/include/public/arch-arm.h
> +++ b/xen/include/public/arch-arm.h
> @@ -333,6 +333,11 @@ struct xen_arch_domainconfig {
>       *
>       */
>      uint32_t clock_frequency;
> +    /*
> +     * OUT
> +     * Guest physical address space size
> +     */
> +    uint8_t gpaddr_bits;

... this being an OUT field. Is this really what Andrew had asked for?
I would have expected the entire struct to be IN (and the comment at
the top of the containing struct in public/domctl.h also suggests so,
i.e. your new field renders that comment stale). gic_version being
IN/OUT is already somewhat in conflict ... One of the problems with
_any_ of the fields being OUT is that then it is unclear how the output
is intended to be propagated to consumers other than the entity
creating the domain.

Jan