Laine Stump <laine@xxxxxxxxxx> writes: > On 12/15/2016 05:12 AM, Marcel Apfelbaum wrote: >> On 12/14/2016 10:10 PM, Laine Stump wrote: >>> On 12/14/2016 12:17 PM, Marcel Apfelbaum wrote: >>>> Be aware that 1 slot doesn't necessarily refer to only one device, >>>> we can have a multi-function device. >>> >>> Is that a fixed thing? I mean, is it always possible to use all 8 >>> functions of a slot (assuming no hotplug of course)? >>> >> >> Yes, you simply add to the function 0 on command line: with -device >> ...,multifunction=on. > > Yes, I know how the commandline works. my question is whether *all* > PCI controllers in existence have 8 usable functions per slot, or if > that might be another thing that is different from one controller to > the next (and thus would have to be reported in these query > responses). Quote from PCI Express Base Specification Revision 3.0: "Each non-ARI Device may contain up to eight Functions. Each ARI Device may contain up to 256 Functions." The address format is defined by the PCI spec: bus number is 8 bits, device number is 5, function number is 3. However, a device may be an ARI device (ARI = Alternative Routing-ID Interpretation), and then the device number bits are instead used for a wider function number. As far as I know, this is PCIe-only. See PCI Express Base Specification Revision 3.0, 6.13. Alternative Routing-ID Interpretation (ARI). -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
