On Tue, Jul 04, 2017 at 07:25:41PM +0100, Mark Cave-Ayland wrote: > Hi all, > > I've been working on a patchset that brings the sun4u machine on > qemu-system-sparc64 much closer to a real Ultra 5, however due to > various design restrictions I need to be able to restrict how devices > are added to the machine with -device. > > On a real Ultra 5, the root PCI bus (sabre) has 2 PCI bridges (simba A > and simba B) with the onboard devices attached to simba A with 2 free > slots, and an initially empty simba B. > > Firstly, is it possible to restrict the machine so that devices cannot > be directly plugged into the root PCI bus, but only behind one of the > PCI bridges? There is also an additional restriction in that slot 0 > behind simba A must be left empty to ensure that the ebus (containing > the onboard devices) is the first device allocated. > > Secondly, how does libvirt handle these type of restrictions? Is it able > to get the information from QEMU or is there some kind of libvirt > profile that needs to be updated? And do newer versions of libvirt have > the ability to attach devices behind PCI bridges using a GUI such as > virt-manager, or is that only something that can only be done by > directly editing the domain XML?
Libvirt has a bunch of code that provides different logic for various machine types when doing addressing & setting up default PCI controllers. Libvirt support for sparc machine types almost certainly broken since I'm not aware of anyone having looked at it forever. Probably best to re-ask your Q's on the libvir-list to get info from the people familiar with this, since I'm fuzzy on precise details of what you'd need todo. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
