Hi Marcin, Hope you have compiled the qemu with virtfs enabled.i.e --enable-virtfs
And the cli looks like this. But I am working on x86 not ARM. -fsdev local,id=root,path=${ROOTFS},security_model=none,writeout=immediate -device virtio-9p-pci,fsdev=root,mount_tag=/dev/root -Regards, Pradeep On 27 September 2016 at 21:33, mar.krzeminski <mar.krzemin...@gmail.com> wrote: > So for some reason kernel expect that 9pfs channel will be named /dev/root > (root= seem to be ignored). > Working command line: > > Kernel: /root=/dev/root rootfstype=9p rootflags=trans=virtio rw/ > Qemu: /-device virtio-9p-device,fsdev=host_fs,mount_tag=/dev/root -fsdev > local,id=host_fs,security_model=none,path=////work/rootfs/ > / > Thanks, > Marcin/ > / > W dniu 23.09.2016 o 21:41, mar.krzeminski pisze: > > And most important, while mounting as roots, error is: >> >> [ 1.086235] device: '9p-1': device_add >> [ 1.087859] 9pnet_virtio: no channels available >> [ 1.091619] device: '9p-1': device_unregister >> [ 1.092783] device: '9p-1': device_create_release >> [ 1.093534] VFS: Cannot open root device "host" or unknown-block(0,0): >> error -2 >> >> Thanks, >> Marcin >> >> W dniu 23.09.2016 o 21:38, mar.krzeminski pisze: >> >>> Hello, >>> >>> I have a problem in my custom arm machine to use 9p fs as a rootfs. >>> >>> 9p command line i qemu: >>> >>> /-device virtio-9p-device,fsdev=host_fs,mount_tag=hostfs -fsdev >>> local,id=host_fs,security_model=none,path=/work/rootfs/ >>> >>> Kernel cmd line: >>> >>> /--append "root=hostfs rootfstype=9p rootflags=trans=virtio noinitrd >>> console=ttyS3,115200" >>> >>> /Device tree entry: >>> >>> / virtio: virtio_mmio@ff0a4000 {// >>> // compatible = "virtio,mmio";// >>> // reg = <0xff0a4000 0x200>;// >>> // interrupts = <0 72 1>;// >>> // status = "okay";// >>> // }; >>> >>> >>> / I can mount this fs from kernel using fstab entry: >>> /hostfs /mnt/host 9p trans=virtio 0 0 >>> >>> /Do you have any idea what am I doing wrong? >>> >>> Thanks, >>> Marcin/ >>> / >>> >> >> >