On 23.11.2022 10:41, Jan Beulich wrote: > On 22.11.2022 21:25, Julien Grall wrote: >> On 21/11/2022 16:40, Jan Beulich wrote: >>> On 21.11.2022 17:23, Carlo Nonato wrote: >>>> This would be really good. The only problem I can see is the p2m allocation >>>> which is done during domain creation. With the current set of patches it >>>> results in a "Failed to allocate P2M pages" since we want to have p2m >>>> tables >>>> allocated with the same color of the domain and a null page is returned >>>> because we have no colors. >>> >>> Hmm, I see. It would seem to me that this p2m init really is happening >>> too early. Ideally domain_create would merely mean creating a largely >>> empty container, with stuff being populated subsequently as necessary. >> >> The vGIC is not optional. So to me it sounds wrong to defer the decision >> to after the domain is created. >> >> It is not clear to me how you would check that mandatory components have >> been properly initialized. > > There could be final checking right before unpausing a domain for the > first time. > >>> But I guess this is too much of a re-work to be done in the context >>> here, plus of course I may be overlooking something which actually >>> makes it necessary for domain creation to be structured the way it is >>> right now. (Imo the reason for the early minimal population of the p2m, >>> added only quite recently, wasn't a good one, and the vGIC init would >>> better be deferred. Yet once again I may lack details on why that's not >>> possible.) >> >> See above for the theoritical part. For the practice part, we need to >> know the vGIC version at domain creation because it impact the maximum >> of vCPU we can expose. > > Sure - I didn't suggest to leave that information out of domain_create. > >> It is also not very clear where this could be initialized. Are you >> suggesting to add an extra mandatory hypercall? FAOD, I don't think >> p2m_set_allocation() would be the right place. > > I agree with the latter - that would at best be a bodge. And yes, I was > thinking of having a separate domctl for that purpose.
The expand further: I think setvnumainfo would also better be issued before _any_ memory allocations for a domain. And I view vNUMA data as kind of comparable to the coloring data here. Jan
