On Sun, Aug 30, 2020 at 10:52 PM Gerd Hoffmann <kra...@redhat.com> wrote: > > Hi, > > > > > that newer hardware for a more modernized IOAPIC? Or would something > > > > like hacking the 82093AA emulation code to support more than 24 IRQs > > > > be within the realm of possibility? Is it even meaningful for guest > > > > VMs to "think" they're talking to an ancient IOAPIC from 1996? > > > > > > I think that extending an existing real device is potentially > > > problematic. We don't know what dependencies closed source OSes might > > > have or what they'd infer from the device. If you can't find a > > > specific device with widespread support to emulate, maybe it would be > > > possible to implement a generic device. Does this really solve the > > > problem though, or is it just a stopgap? How would we size the ioapic > > > to match the VM hardware configuration? > > > > Do you mean what if we update it to support N IRQs and someone comes > > around and wants >N IRQs? If this is liable to happen in the future > > that seems to suggest not emulating any real piece of IOAPIC HW. > > > > I guess giving the 82093AA more lines is the kind of thing that could > > be behind a Kconfig flag for kvm. Not sure if that makes it ok though. > > It would probably be easier to just have multiple ioapics. NUMA > machines sometimes have one ioapic per node, and guests should be able > to handle that just fine without kvm-specific hacks.
Interesting, I hadn't thought of that. Thanks for the suggestion! I'll mention it in the email I'm about to send to the KVM list. > > take care, > Gerd > _______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users
