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

[Bhushan Bharat-R65777]

> -----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>.

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