Re: [PATCH for-4.16 v6] gnttab: allow setting max version per-domain

[Ian Jackson <iwj@xxxxxxxxxxxxxx>]

Roger Pau Monne writes ("[PATCH for-4.16 v6] gnttab: allow setting max version 
per-domain"):
> Introduce a new domain create field so that toolstack can specify the
> maximum grant table version usable by the domain. This is plumbed into
> xl and settable by the user as max_grant_version.
> 
> Previously this was only settable on a per host basis using the
> gnttab command line option.
> 
> Note the version is specified using 4 bits, which leaves room to
> specify up to grant table version 15. Given that we only have 2 grant
> table versions right now, and a new version is unlikely in the near
> future using 4 bits seems more than enough.
> 
> xenstored stubdomains are limited to grant table v1 because the
> current MiniOS code used to build them only has support for grants v1.
> There are existing limits set for xenstored stubdomains at creation
> time that already match the defaults in MiniOS.
...
> This needs to be applied on top of Andrew's:
> 
> xen: Report grant table v1/v2 capabilities to the toolstack
> https://lore.kernel.org/xen-devel/20211029173813.23002-1-andrew.cooper3@xxxxxxxxxx/

Thanks.

We have discussed this wrt 4.16.  I am minded to grant a release ack
for this.  If anyone has a contrary opinion please speak now.

(I think committing both of these would be subject to maintainer acks
for "Report grant table v1/v2 capabilities", which I didn't see but
perhaps I am missing.)

Thanks,
Ian.