On Tue, 2011-05-17 at 23:27 +0300, Sasha Levin wrote: > On Tue, 2011-05-17 at 22:08 +0300, Sasha Levin wrote: > > 'kvm_9p' isn't created as a device under /dev, it's just a name used > > internally by 9pnet_virtio (and located under sysfs). > > > > I couldn't figure out which params the kernel would expect to boot using > > 9p over virtio (theres no device name to begin with). > > > > I've also couldn't find anything that suggested it's possible to boot > > using virtio-9p as rootfs. > > Ignore that. > > Naming the virtio transport "/dev/root" and passing proper params to the > kernel makes it work: > > [ 1.844983] VFS: Mounted root (9p filesystem) on device 0:11. > > I'll make some changes to the virtio-9p patch to make it easier for the > user to do that. > Just to sum the '9p bootability' discussion, It is possible to boot from virtio-9p devices. The sample disk image provided by qemu (the one we link in our README) boots just fine. I've had to use a 2.6.39 kernel when booting, using the 2.6.37 kernel which we have in kvm tools tree doesn't work. I haven't investigated why yet. Transport name must be called "/dev/root". Both when defining it for the virtio transport and in the kernel root= parameter. Changing either of them leads to: '9p: no channels available'. Here is the command line I've used (rootfs/ is a mount of 'linux-0.2.img'): ./kvm run -m 256 --virtio-9p rootfs/ --params "root=/dev/root rootflags=rw,trans=virtio,version=9p2000,debug=0x00 rootfstype=9p rw" -k /boot/bzImage When trying to boot a distribution rootfs we get a lot of symbolic link and file locking errors, since neither of those is supported by legacy 9p2000 - thats understandable. It just prevents from almost anything more complicated than simple command line from working properly. -- Sasha. -- 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
