On Thu, Mar 27, 2014 at 08:06:15PM +0100, Kay Sievers wrote: > On Thu, Mar 27, 2014 at 7:59 PM, Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > > On Thu, Mar 27, 2014 at 07:43:34PM +0100, Kay Sievers wrote: > >> On Thu, Mar 27, 2014 at 6:30 PM, Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > >> > >> > If the virtio device is a PCI device, it is really best to > >> > treat it like you treat any other PCI function (I guess you mean > >> > function and not device, right? We support multifunction > >> > devices and some people do pack multiple NICs in a single device).. > >> > > >> > At the moment many devices in a single pci function can not happen on a > >> > PCI system (no multiport) but if we add multiport, we'll follow some > >> > existing standard to expose this information to the guest. > >> > >> This means, that there can currently never multiple devices below one > >> and the same virtio parent device? > > > There's a single virtio device per pci function (you keep saying > > device but I hope the distinction is clear and this is > > just slip of the tongue). > > Right, we talks about sysfs directories and they are called "device", > we don't really care about the actual bus that is implemented, > userspace does not really know much about them. :) > > > For net devices under a pci function that is also currently the case, > > but I can't yet tell you for sure ahead of the time how we'll present > > multiport devices if we ever implement them. > > > > I'm guessing there will be multiple net devices under > > a single pci device and we'll present a sysfs attribute with the port > > number in this case. > > > > Hmm maybe we should go ahead and add a place-holder > > attribute so that it's future-proof? > > > > I'll write a patch like that and we'll see how it's accepted. > > Netdevs with multiple ports are represented with the standard "dev_id" > attribute identifying the instance of the driver per parent "device"; > should all work already from the userspace side, if the virtio side > would use that too. > > Kay Aha. In that case it's easy - pls assume that if and when we implement multiple we'll just follow standards and use dev_id. For virtio pci devices specifically virtio<->pci 1:1 mapping is set in stone in the spec. Non pci ones need to be examined separately. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
