2018-05-24 1:33 GMT+08:00 Marcel Apfelbaum <marcel.apfelb...@gmail.com>: > >> * IOMMUs cannot span domains either, so bringing new domains introduces >> the need >> to add a VT-d DHRD or vIOMMU per PCIe domain > > > Not really, you may have PCI domains not associated to an vIOMMU. As a first > step, > you should not deal with it. The IOMMU can't span over multiple domains, > yes. >
OK, I'll leave IOMMU part at present. >> * 64-bit space is crowded and there are no standards within QEMU for >> placing per >> domain 64-bit MMIO and MMCFG ranges > > > Yes, but we do have some layout for the "over 4G" area and we can continue > building on it. That sounds good. >> * NUMA modeling seems to be a stronger motivation than the limitation of >> 256 but >> nubmers, that each NUMA node holds its own PCI(e) sub-hierarchy > > > No, the 256 devices limitation is the biggest issue we are trying to solve. Great, the initial purpose still holds. > You are on the right path, this discussion is meant to help you understand > wider concerns > and make you aware of different constrains we didn't think about. > > Good luck with the next version! It is indeed very helpful. I'll try to deal with (at least most of) the issues int v2. Thanks for your valuable reviews! Zihan
