On Thu, Sep 10, 2020 at 09:53:03AM +0800, Jason Wang wrote: > > Maybe it would be good too that vhost provides real 4k-aligned addresses (in > > vhost_iotlb_miss)? My understanding is that PCI_ATS_CAP_PAGE_ALIGNED will > > be > > more compatible than without the bit set. > > > Yes, I've considered this. But the problem is that: > > 1) vhost itself can generate unaligned request (since its IOTLB doesn't have > any alignment requirement) > 2) the IOTLB miss processing in qemu doesn't do anything with ATS, we > shortcut PCI by calling the address_space_get_iotlb_entry() > > So I'm not quite sure it's worth to do that consider we don't emulate ATS > via PCI actually :)
True. :) Though we still need to make sure e.g. each translate() iommu op will drop those bits properly, but I agree that should be trivial. -- Peter Xu
