Hi, On Mon, Mar 22, 2010 at 03:14:48PM +0000, Paul Brook wrote: > > > John attempted this and it was reverted because the implementation > > > exhausted the PCI config space. > > > > I don't understand that. Existig hardware devices dump much more of > > their data such as vendor and model type information into the config > > space, how can using a field that real hardware uses exhaust the > > config space? > > I think you (collectively) are confusing three different things:
Perfectly accepted. I don't know zilch about today's hardware, I am not a developer but only a systems administrator wishing for some more flexibility in a software that I use every day. > - PCI config space: Not used in any significant way other than the standard > fields (i.e. basic device ID and configuring BARs). Slow/hard to access. > > - PCI IO BAR: Used by virtio-pci devices to expose the virtio config space. > Extremely limited resource (max. 64k for the whole system). On real hardware > only really used for legacy interfaces because it's slow, cumbersome, and x86 > specific. Unfortunately it currently seems to lower overhead than MMIO on > KVM > :-( > > - PCI MEM BAR (usually MMIO): How real devices expose themselves. Relatively > large address space (megabytes) available. Looks like PCI MEM BAR may be the way to go. Greetings Marc -- ----------------------------------------------------------------------------- Marc Haber | "I don't trust Computers. They | Mailadresse im Header Mannheim, Germany | lose things." Winona Ryder | Fon: *49 621 72739834 Nordisch by Nature | How to make an American Quilt | Fax: *49 3221 2323190
