Re: [Qemu-devel] Running KVM guest on X86

[Gleb Natapov]

On Tue, Aug 07, 2012 at 06:30:05AM +0000, Bhushan Bharat-R65777 wrote:
> 
> 
> > -----Original Message-----
> > From: Alex Williamson [mailto:address@hidden
> > Sent: Monday, August 06, 2012 9:27 PM
> > To: Bhushan Bharat-R65777
> > Cc: address@hidden; Avi Kivity
> > Subject: Re: Running KVM guest on X86
> > 
> > On Mon, 2012-08-06 at 15:40 +0000, Bhushan Bharat-R65777 wrote:
> > > Hi Avi/All,
> > >
> > > I am facing issue to boot KVM guest on x86 (I used to work on PowerPC 
> > > platform
> > and do not have enough knowledge of x86). I am working on making VFIO 
> > working on
> > PowerPC Booke, So I have cloned Alex Williamsons git repository, compiled 
> > kernel
> > for x86 on fedora with virtualization configuration (selected all kernel 
> > config
> > options for same). Run below command to boot Guest (I have not provided vfio
> > device yet):
> > >
> > > "qemu-system-x86_64 -enable-kvm -m 1024 -nographic -kernel
> > arch/x86_64/boot/bzImage -initrd /boot/initramfs-3.5.0-rc4+.img -serial
> > tcp::4444,server,telnet"
> > >
> > > After the I can see qemu command line (able to run various commands like 
> > > "info
> > registers" etc), while guest does not boot (not even the first print comes).
> > >
> > > Can anyone help in what I am missing or doing wrong?
> > 
> > x86 doesn't use the serial port for console by default, so you're making 
> > things
> > quite a bit more difficult that way.  Typically you'll want to provide a 
> > disk
> > image (the -hda option is the easiest way to do this), a display (-vga std 
> > -vnc
> > :0 is again easiest), and probably something to install from (-cdrom
> > <image.iso>).  You can also add a -boot d to get it to choose the cdrom the
> > first time for install.  Thanks,
> 
> Thanks Avi and Alex, I can see the KVM guest boot prints by adding -append 
> "console=ttyS0"
> 
> Now my exact command is like: 
> "qemu-system-x86_64 -enable-kvm -nographic -nodefconfig -kernel 
> /boot/vmlinuz-3.5.0+  -initrd /boot/initramfs-3.5.0+.img -append 
> "console=ttyS0" -hda fedora.qcow  -m 1024"
> 
>   Where fedora.qcow is created by "qemu-img create fedora.qcow 5G"
> 
> With this it is falling to Dracut, below are the error prints:
> 
> --------------------
> [    2.288931] dracut: FATAL: No or empty root= argument
> [    2.291808] dracut: Refusing to continue
> 
> 
> [    2.294721] dracut Warning: Signal caught!
> dracut Warning: Signal caught!
> [    2.298894] dracut Warning: dracut: FATAL: No or empty root= argument
> dracut Warning: dracut: FATAL: No or empty root= argument
> [    2.304713] dracut Warning: dracut: Refusing to continue
> dracut Warning: dracut: Refusing to continue
> 
> [    2.320311] init (1) used greatest stack depth: 2664 bytes left
> [    2.323851] Kernel panic - not syncing: Attempted to kill init! 
> exitcode=0x00000100
> [    2.323851] 
> [    2.324551] Pid: 1, comm: init Not tainted 3.5.0+ #7
> [    2.324551] Call Trace:
> [    2.324551]  [<ffffffff8171c34e>] panic+0xc6/0x1e1
> [    2.324551]  [<ffffffff81729be0>] ? _raw_write_unlock_irq+0x30/0x50
> [    2.324551]  [<ffffffff810c0020>] do_exit+0xa20/0xb70
> [    2.324551]  [<ffffffff8172a215>] ? retint_swapgs+0x13/0x1b
> [    2.324551]  [<ffffffff810c04bf>] do_group_exit+0x4f/0xc0
> [    2.324551]  [<ffffffff810c0547>] sys_exit_group+0x17/0x20
> [    2.324551]  [<ffffffff81732d69>] system_call_fastpath+0x16/0x1b
> -----------------
> 
> Should I mount the root-file-system in disk and pass -append 
> "root=<mount-path>.
> 
Yes, you should. Not <mount-path>, but root device. Something like
"root=/dev/sda1"

> I had no luck when I tried "qemu-system-x86_64 -device 
> virtio-scsi-pci,id=scsi  -enable-kvm  -nographic -nodefconfig -nodefaults  
> -chardev stdio,id=charserial0  -device 
> isa-serial,chardev=charserial0,id=serial0  -drive 
> file=fedora.qcow,if=none,id=sda  -device scsi-disk,bus=scsi.0,drive=sda  
> -device sga  -kernel /boot/vmlinuz-3.5.0+  -initrd /boot/initramfs-3.5.0+.img 
>  -append "console=ttyS0" -m 1024"
>  
> 
> Thanks in Advance
> -Bharat
> 

--
                        Gleb.