On Tue, Feb 24, 2009 at 10:35:37PM +0000, Mark McLoughlin wrote: > Hi, > The following two patches build on the previous series. > > The idea is simple - when starting a guest, we should > automatically dettach and reset any devices assigned to it. > > Rather than change the semantics of the existing > hostdev source, we only do this when the node device name is > used as the hostdev source. Directly specifying the device > address rather than its name can be seen as an option for > people who know what they're doing. I don't like this idea really. The reason we use the PCI address in the XML is because that is a guarenteed stable identifier. The names given to nodedevices are currently under such a guarentee. So if we used the nodedev naming and then a Fedora release switched from HAL to DeviceKit nodedev drivers, any guests with PCI devs attached wouuld be broken. NB, I *do* think we should define a standard stable naming for nodedevs, that is identical whether using HAL of DeviceKit, but even if we had that I don't particularly like idea of using the names here when we already have a workable addressing scheme in the XML. If we want to indicate whether the HV or caller should be responsible for attach/detach/reset operations, we should just add some boolean flag to the <hostdev> element. We'll also likely need to add something to the capabilities XML format to identify what PCI passthrough features are supported by a HV. eg, With your KVM patches we can mange the attach/detach/reset stuff internally, or leave it upto the mgmt app. The Xen impl though will have no such choice currently - XenD expects that you've done the attach/detach yourself, and merely does the reset stuff internally. Perhaps allow for autoattach="yes|no" or managed="yes|no" to indicate whether we should do a detach/attach internally or not. Regards, Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :| -- Libvir-list mailing list Libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list