On (Wed) Aug 05 2009 [13:00:57], Anthony Liguori wrote: > Jamie Lokier wrote: >> Anthony Liguori wrote: >> >>> Richard W.M. Jones wrote: >>> Have you considered using a usb serial device? Something attractive >>> about it is that a productid/vendorid can be specified which means >>> that you can use that as a method of enumerating devices. >>> >>> Hot add/remove is supported automagically. >>> >> >> The same applies to PCI: productid/vendorid (and subids); >> PCI hotplug is possible though not as native as USB. >> > > What's nice about USB is that HID specifies quite a few functional > generic devices that can be extended to increase functionality. This > means you can implement a more sophisticated usb device that satisfies > the serial interface, provide a special more featureful driver for > Linux, and just use normal serial for Windows. > > The downside is that USB emulation stinks. And the virtio code is pretty simple and self-contained. I don't see why we'd restrict us more to use something else. >> Here's another idea: Many devices these days have a serial number or >> id string. E.g. USB storage, ATA drives, media cards, etc. Linux >> these days creates alias device nodes which include the id string in >> the device name. E.g. /dev/disks/by-id/ata-FUJITSU_MHV2100BH_NWAQT662615H >> >> So in addition to (or instead of) /dev/vmch0, /dev/vmch1 etc., >> Linux guests could easily generate: >> >> /dev/vmchannel/by-role/clipboard-0 >> /dev/vmchannel/by-role/gueststats-0 >> /dev/vmchannel/by-role/vmmanager-0 >> >> It's not necessary to do this at the beginning. All that is needed is >> to provide enough id information that will appear in /sys/..., so that >> that a udev policy for naming devices can be created at some later date. > > Well my thinking is that the "clipboard" device actually becomes a USB > serial device. It's easy to enumerate and detect via the existing Linux > infrastructure. Plus usb drivers can be implemented in userspace which > is a nice plus (cross platform too via libusb). Sure; but there's been no resistance from anyone from including the virtio-serial device driver so maybe we don't need to discuss that. Amit -- 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
