[fedora-arm] Updated Fedora ARM qemu images?

[Alex Villací­s Lasso]

El 23/03/12 01:19, Richard W.M. Jones escribió:
> I cannot get qemu-system-arm to boot any of our F17 kernels, but
> here's what I did anyway.
>
> # Make a disk image:
>
> $ wget 'http://fedora.roving-it.com/rootfs-f17-hfp-alpha1.tar.bz2'
> $ bunzip2 rootfs-f17-hfp-alpha1.tar.bz2
> $ virt-make-fs -s 2G -t ext3 -F raw --partition=mbr rootfs-f17-hfp-alpha1.tar disk.img
> Formatting 'disk.img', fmt=raw size=2147483648
> $ ll disk.img
> -rw-r--r--. 1 rjones rjones 2147483648 Mar 23 05:47 disk.img
> $ virt-filesystems -a disk.img --all --long -h
> Name       Type        VFS   Label  MBR  Size  Parent
> /dev/sda1  filesystem  ext3  -      -    2.0G  -
> /dev/sda1  partition   -     -      83   2.0G  /dev/sda
> /dev/sda   device      -     -      -    2.0G  -
>
> # Extract the kernels from the tarball:
>
> $ tar tf rootfs-f17-hfp-alpha1.tar | less
> $ tar xf rootfs-f17-hfp-alpha1.tar ./boot/
>
> # Try to boot it one of the kernels in the boot/ directory:
>
> $ qemu-system-arm -m 256 -M versatilepb -kernel boot/vmlinuz-3.3.0-0.rc4.git3.1.fc17.armv7hl -initrd boot/initramfs-3.3.0-0.rc4.git3.1.fc17.armv7hl.img -hda disk.img -serial stdio -vga std
> Uncompressing Linux... done, booting the kernel.
>
> It just hangs at this point using 100% CPU with no output.  The other
> kernels don't even seem to get that far.
>
> Rich.
>
I have not tried fc17 yet, but I had the same problem with the fc15 rootfs at first. I eventually succeeded with this command line:

qemu-system-arm -nographic  -M versatilepb -kernel boot/vmlinuz-2.6.42.2-1.fc15.armv5tel -initrd boot/initramfs-2.6.42.2-1.fc15.armv5tel.img -append "root=LABEL=rootfs console=ttyAMA0" -hda fedora-15-arm.vmdk -net nic,vlan=0 -net 
tap,vlan=0,ifname=tap0,script=../qemu-ifup

The explanation:

The Fedora ARM kernel for fc15 (and possibly for fc17 too) does *not* make use of the emulated graphic device provided by qemu-system-arm. The device driver is not compiled as part of the kernel, but as a separate module, so there is no framebuffer device 
for the kernel to display anything. If you get root access to the machine through some other means, you can eventually modprobe the driver, and you will see some output. I think the parameter -vga std will do nothing to help, as this is probably x86-only.

To see the boot process, you need at least console=ttyAMA0 as a kernel commandline. If you do not use -nographic , then you can switch to the serial console output with Ctrl-Alt-[1,2,3]. I use -nographic to send the serial output to stdout and save on 
useless graphic windows. You will also need a login console in ttyAMA0. You can do this (at least on fc15) by mounting the final filesystem, and adding a symlink that represents the need to maintain a login console on ttyAMA0:

[palosanto at rpmbuild-arm getty.target.wants]$ ls -l /etc/systemd/system/getty.target.wants/serial-getty\@ttyAMA0.service
lrwxrwxrwx. 1 root root 41 mar  1 17:15 /etc/systemd/system/getty.target.wants/serial-getty at ttyAMA0.service -> /lib/systemd/system/serial-getty at .service

You also need the root=XXX parameter. If you label the root filesystem and use the standard initrd, then you can use the same label in the kernel parameter (root=LABEL=rootfs) . I used "rootfs" because that is the label in the default /etc/fstab in the 
fc15 filesystem.

If the kernel runs correctly, you should see the message "Uncompressing Linux... OK, booting the kernel" in the serial output of qemu-system-arm, followed by the boot process messages. If you see no "Uncompressing Linux", maybe armv7hl is the wrong kernel 
to use, and you should stick to armv5tel.