On Sun, Sep 11, 2011 at 09:51:06PM +0300, Michael S. Tsirkin wrote: > On Sun, Sep 11, 2011 at 12:01:49PM -0300, Marcelo Tosatti wrote: > > On Sun, Sep 11, 2011 at 12:23:57PM +0300, Michael S. Tsirkin wrote: > > > On Fri, Sep 09, 2011 at 03:34:26PM -0300, Marcelo Tosatti wrote: > > > > > > something I noted when readin our acpi code: > > > > > > we currently pass eject request for function 0 only: > > > > > > Name (_ADR, nr##0000) > > > > > > We either need a device per function there (acpi 1.0), > > > > > > send eject request for them all, or use ffff > > > > > > as function number (newer acpi, not sure which version). > > > > > > Need to see which guests (windows,linux) can handle which form. > > > > > > > > > > I'd guess we need to change that to ffff. > > > > > > > > No need, only make sure function 0 is there and all other functions > > > > should be removed automatically by the guest on eject notification. > > > > > > Hmm, the ACPI spec explicitly says: > > > > > > High word = Device #, Low word = Function #. > > > (e.g., device 3, function 2 is 0x00030002). To refer > > > to all the functions on a device #, use a function > > > number of FFFF). > > > > Right, but this is the _ADR of the device instance in ACPI. > > The communication between QEMU and the ACPI DSL code is all > > based in slots. > > It's easy to extend that if we like though. > > > > > ACPI PCI hotplug is based on slots, not on functions. It does not > > > > support addition/removal of individual functions. > > > > > > Interesting. Is this just based on general logic, > > > reading of the linux driver or the ACPI spec? > > > > Its based on Seabios ACPI DST implementation and its relationship with > > the QEMU implementation in acpi_piix4.c. > > > > > The ACPI spec itself seems pretty vague. All tables > > > list devices, where each device has an _ADR entry, > > > which is built up of PCI device # and function #. > > > > Yes, it is vague. Given the mandate from the PCI spec a device _must > > contain_ function 0, usage (including hotplug/unplug) of individual > > functions other than 0 as separate devices is a no-go. > > It doesn't seem to be a big issue. > We could, for example, keep a stub function 0 around. I suppose the guest will remove all functions of a device once you attempt to hot-unplug a function. What is the problem with adding more PCI buses, instead of multifunction ? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
