On Thu, May 09, 2013 at 10:31:04AM +1000, David Gibson wrote: > The current PCI subsystem has kind of half-hearted support for > multiple independent root buses - aka PCI domains - in the form of the > PCIHostBus structure and its domain field. However, it doesn't quite > work because pci_host_bus_register() is always called with a domain of > 0. > > Worse, though, the whole concept of numbered domains isn't general > enough. Many platforms can have independent root buses (usually on > wholly independent host bridges), but only x86 gives them a > hardware-significant domain number, essentially as a hack to allow all > the separate config spaces to be accessed via the same IO ports. > Linux guests on other platforms will show domain numbers in lspci, but > these are purely guest assigned, so qemu won't know about them. > > This patch series, therefore, removes the broken-as-is domain concept > from qemu, and replaces it with a different way of handling multiple > root buses, based on a host bridge class method to provide a > identifier for the root bus. This hook is designed in such a way as > to allow a single bridge object to support mutiple root buses with > future changes, which will allow future implementations of x86 north > bridges with multiple domains to be supported correctly, and in way > that matches the existing practice for all external interfaces.
I absolutely agree this area needs to be cleaned up. Going on vacation and haven't had a chance to look at the patches yet. Sorry. Will respond early next week, hopefully. Thanks for your patience, -- MST
