On Sun, Nov 29, 2015 at 10:46:03AM +0200, Marcel Apfelbaum wrote: > On 11/27/2015 07:28 PM, Eduardo Habkost wrote: > >On Thu, Nov 26, 2015 at 06:00:28PM +0200, Marcel Apfelbaum wrote: > >>Add bus property to PC machines and use it when looking > >>for primary PCI root bus (bus 0). > >> > >>Signed-off-by: Marcel Apfelbaum <mar...@redhat.com> > > > >I can't pretend I have reviewed the q35 part, but the changes are > >an improvement to the existing code that depended on > >find_i440fx(). > > > >Acked-by: Eduardo Habkost <ehabk...@redhat.com> > > Thanks! > > > > >BTW, what's missing to allow us to change acpi_set_pci_info() to > >use PCMachine::bus instead of find_i440fx(), too? How much of the > >PCI hotplug stuff is different in q35? > > It is pretty different. > i440fx has acpi based hotplug while q35 has PCIe native hotplug. Since is > "native", no acpi info is necessary. > > Having said that, if we have an PCIe-PCI bridge, the pci devices behind it > cannot be hotplugged/unplugged right now. > > Once we decide to add hotplug support for this scenario, maybe we can get rid > of > find_i440fx().
Thanks for the explanation. I wonder if there's a better way to check if ACPI-based hotplug is needed by looking at PCMachineState or PCIBus, so we don't couple the ACPI code to piix.c. -- Eduardo
