On 15.10.2021 11:39, Jan Beulich wrote:
> On 22.09.2021 10:21, Roger Pau Monne wrote:
>> --- a/xen/include/public/domctl.h
>> +++ b/xen/include/public/domctl.h
>> @@ -87,14 +87,22 @@ struct xen_domctl_createdomain {
>> /*
>> * Various domain limits, which impact the quantity of resources
>> * (global mapping space, xenheap, etc) a guest may consume. For
>> - * max_grant_frames and max_maptrack_frames, < 0 means "use the
>> - * default maximum value in the hypervisor".
>> + * max_grant_frames, max_maptrack_frames and max_gnttab_version < 0
>> + * means "use the default maximum value in the hypervisor".
>> */
>> uint32_t max_vcpus;
>> uint32_t max_evtchn_port;
>> int32_t max_grant_frames;
>> int32_t max_maptrack_frames;
>>
>> +/* Grant version, use low 4 bits. */
>> +#define XEN_DOMCTL_GRANT_version_mask 0xf
>> +#define XEN_DOMCTL_GRANT_version_default 0xf
>> +
>> +#define XEN_DOMCTLGRANT_MAX XEN_DOMCTL_GRANT_version_mask
>> +
>> + uint32_t grant_opts;
>
> As it now seems unlikely that this will make 4.16, please don't forget
> to bump the interface version for 4.17. With that and preferably with
> the nit above addressed, hypervisor parts:
> Reviewed-by: Jan Beulich <jbeul...@suse.com>
Actually no, I'm afraid there is an issue with migration: If the tool
stack remembers the "use default" setting and hands this to the new
host, that host's default may be different from the source host's. It
is the effective max-version that needs passing on in this case, which
in turn requires a means to obtain the value.
Jan
