Re: [libvirt] [PATCH 1/2] qemu: aarch64: Don't add PCIe controller by default

On 01/28/2016 04:14 PM, Cole Robinson wrote: >  > This was discussed here: >  > https://www.redhat.com/archives/libvir-list/2015-December/msg00217.html >  > The summary is that apps/users are in a tough spot WRT aarch64 -M virt > and PCIe support: qemu has all the plumbing, but most distros don't > support it yet. Presently libvirt adds a PCIe controller to the XML for > new enough qemu, but this patch drops that behavior. I read back through all of these messages and am more thoroughly  undecided than ever about the proper thing to do.

I guess the end of that thread was that the best thing to do was (as  you're doing in this patch) to temporarily (?) not add a pcie-root  controller to a domain's XML for aarch64 -M virt, and if there is no PCI  controller, then use virtio-mmio for the address of all devices; but if  a pcie-root is manually added, to instead use pci addresses.   My main issue with that is that the XML is then not reflecting the  hardware exactly in cases where the binary is creating a pcie-root  automatically (but we're not using it). The alternative would be to  force specifying the address type of each device though, and since that  is impractical for management apps to deal with, I guess keying off the  presence/absence of a manually-created pcie-root is the less evil of the  options :-P.