Re: [PATCH v3 07/13] libs/guest: obtain a compatible cpu policy from two input ones

[Jan Beulich <jbeulich@xxxxxxxx>]

On 04.05.2021 13:56, Roger Pau Monné wrote:
> On Mon, May 03, 2021 at 12:43:08PM +0200, Jan Beulich wrote:
>> On 30.04.2021 17:52, Roger Pau Monne wrote:
>>> +/* Only level featuresets so far. */
>>
>> I have to admit that I don't think I see all the implications from
>> this implementation restriction. All other leaves get dropped by
>> the caller, but it's not clear to me what this means wrt what the
>> guest is ultimately going to get to see.
> 
> This aims to be based on what XenServer does, which I was told is to
> level the featuresets. I think the caller of the function will have to
> fill the part of the policy that cannot be leveled. It's likely new
> helpers will be added to do that as required.
> 
> One option would be to get the default policy for the guest and then
> use xc_cpu_policy_update_cpuid to apply the leveled one.

Could such further plans perhaps be outlined (to a degree at least)
in the description?

Jan