On Thu, Jun 17, 2010 at 02:17:20PM +0300, Michael S. Tsirkin wrote:
On Thu, Jun 17, 2010 at 08:03:08PM +0900, Isaku Yamahata wrote:
This patch set allows seabios to initialize multi pci bus and 64bit BAR.
Currently seabios is able to initialize only pci root bus. However multi pci bus support is wanted because
- more pci bus is wanted in qemu for many slots
- pci express support is commin in qemu which requires multi pci bus.
those patches on Qemu part are under way, though.
Not that I object, but - does it really require multi bus? Why?
I should have explained about pci express a bit more. Express defines root/upstream/upstream port. They are shown to software as pci-to-pci bride. Express slot to which express device is inserted is under a root or downstream port. That means multi bus. Native hot plug is implemented in root or downstream port. Again that means multi bus.
I heard that some windows device driver checks pci-to-pci bridge existence. Perhaps others may know this better.