Re: Problem booting guest with Linux 2.6.3x

[Michael Tokarev <mjt@tls.msk.ru>]

Daniel Bareiro wrote:
> Hi, Alex.
> 
> On Tuesday, 06 October 2009 22:40:11 -0600,
> Alex Williamson wrote:
> 
>>> root  (hd0,1)
>>>  Filesystem type is ext2fs, partition type 0x83
>>> kernel  /boot/vmlinuz-2.6.31.2-dgb root=/dev/hda2 ro quiet console=tty0 console
>>> =ttyS0,38400n8
>>>   [Linux-bzImage, setup=0x3600, size=0x203480]
>>> initrd  /boot/initrd.img-2.6.31.2-dgb
>>>   [Linux-initrd @ 0x1f983000, 0x65c455 bytes]
>>>
>>> Loading, please wait...
>>> WARNING bootdevice may be renamed. Try root=/dev/sda2
>  
>> I think if you boot without the "quiet" option you'll see that your
>> guest IDE disk did in fact get installed as /dev/sda and following the
>> advice of the error message above will allow you to boot the guest.
> 
> I'm using the option "quiet" with both stock kernel and the kernel
> compiled by myself.

It's irrelevant. By using quiet you're hiding the details, that's
what it is about -- what's what Alex is saying.

>> You could boot using the uuid of the partition or label the filesystem
>> to avoid device naming issues between your original lenny kernel and
>> the newer kernel.
> 
> I was trying changing the not swap devices to the uuid form. Although in
> this case the swap device was not detected, the guest boots without
> majors problems. I think that being used the QEMU_HARDDISK names
> provided by udevinfo would have been solved this problem.
> 
> But according to it seems, I could verify that the disks that are passed
> with -hdX in KVM-88 are mapped in 2.6.31.2 guests like SATA/SCSI
> devices. With Linux stock 2.6.26 these are mapped like IDE disks. Can it
> be due to some change in the kernel code related with KVM?

It has nothing to do with kvm.  It's different kernel options, all kernels
since very early 2.6.x are able to see ide disks as hdX or sdX, depending
on the kernel options and modules loaded.  There are 2 drivers for each
IDE controller - IDE/ATA one, which creates hdX, and PATA one which creates
sdX.

/mjt