On 10.06.21 15:02, Jan Beulich wrote: > On 10.06.2021 13:45, Oleksandr Andrushchenko wrote: >> Hi, Jan! >> >> On 10.06.21 13:48, Jan Beulich wrote: >>> On 10.06.2021 12:01, Oleksandr Andrushchenko wrote: >>>> On 10.06.21 10:54, Roger Pau Monné wrote: >>>>> OTOH if we properly trap accesses to the SR-IOV capability (like it >>>>> was proposed in [1] from your references) we won't have to modify OSes >>>>> that want to run as hardware domains in order to handle SR-IOV devices. >>>> Out of curiosity, could you please name a few? I do understand that >>>> >>>> we do want to support unmodified OSes and this is indeed important. >>>> >>>> But, still what are the other OSes which do support Xen + PCI passthrough? >>> I think Roger saying "want" meant to cover ones which currently don't, >>> and which would have to undergo more extensive changes if they were to >>> be enabled. >> Fair enough. Do you think we would also need to re-work the existing code >> >> in Xen to support normal devices (not SR-IOV), e.g. we currently rely on >> >> PHYSDEVOP_XXX and other Linux specifics. > Yes, work in that area would also be needed. For example we'd need to > scan buses / segments as they become accessible. Right now we only scan > segment 0, and even that's only possible because on x86 mmconfig is not > the only way to access config space. > >> And even if SR-IOV is implemented >> >> in Xen this won't allow those OSes to stay unmodified, including FreeBSD. > Of course, it's the nature of PVH (as opposed to HVM) that OSes need > modification. The question is the scope thereof.
Ok, then it seems I need to get [1] back into the picture. I have modified vPCI code a lot for ARM support, so [1] will not apply as is anymore and needs to be re-worked. But, still it can mostly be re-used > Jan > Thank you, Oleksandr [1] https://lists.xenproject.org/archives/html/xen-devel/2018-07/msg01494.html
