On Mon, Aug 22, 2011 at 05:03:53PM -0400, Benjamin Herrenschmidt wrote: > > > I am in favour of /dev/vfio/$GROUP. If multiple devices should be > > assigned to a guest, there can also be an ioctl to bind a group to an > > address-space of another group (certainly needs some care to not allow > > that both groups belong to different processes). > > > > Btw, a problem we havn't talked about yet entirely is > > driver-deassignment. User space can decide to de-assign the device from > > vfio while a fd is open on it. With PCI there is no way to let this fail > > (the .release function returns void last time i checked). Is this a > > problem, and yes, how we handle that? > > We can treat it as a hard unplug (like a cardbus gone away). > > IE. Dispose of the direct mappings (switch to MMIO emulation) and return > all ff's from reads (& ignore writes). > > Then send an unplug event via whatever mechanism the platform provides > (ACPI hotplug controller on x86 for example, we haven't quite sorted out > what to do on power for hotplug yet). Hmm, good idea. But as far as I know the hotplug-event needs to be in the guest _before_ the device is actually unplugged (so that the guest can unbind its driver first). That somehow brings back the sleep-idea and the timeout in the .release function. Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
