Re: Problems with xen and linux 2.26.32 kernels for dom0

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Jun 16, 2010 at 03:00:03PM -0400, Jia Rao wrote:
> Hi all,
> 
> I used to use xen 3.4.2 and linux 2.6.18-xen kernels for both dom0 and domU,
> without any problems.
> 
> Recently, I need to try io bandwidth control like dm-ioband in the new
> kernel 2.6.32 (dm-ioband has patches for this kernel). It gave me a lot of
> problems if I want to upgrade the dom0 to 2.6.32. The following is what I
> tried and the errors.
> 
> 
> Xen: 3.4.3 (I need to stick with 3.4.x. 3.4.3 is the one that can run pvops)
> 
> *First approach:*
> I tried to download pvops from the git repository xen/stable-2.6.32.x. The
> compilation was OK, but the initrd has a lot missing dependencies. I tried
> to use --builtin to claim those missing modules in kernel. However, with the
> generated initrd, dom0 can not boot. I got the error: *unable to locate
> IOAPIC for GSIx and mount: could not find filesystem: /dev/root*.
> I enabled : CONFIG_SYSFS_DEPRECATED=y,  CONFIG_SYSFS_DEPRECATED_V2=y and
> tried to use root=/dev/sdax or root=LABEL=/. No luck.

You did follow the the Wiki:
http://wiki.xensource.com/xenwiki/2.6.18-to-2.6.31-and-higher

and made sure you had the right SATA drivers compiled in? They changed
their names from .18 to .31-and-higher
> 
> *Second approach:*
> Then I switched to the forward ported 2.6.32.13 kernel generated from the
> gentoo xen kernel patches.
> 
> Still xen 3.4.3. After compilation, dom0 booted successfully. However I
> previous domU which has 2.6.18-xen kernels can not boot. It has the same
> error: *mount: could not find filesystem: /dev/root
> *Do I need to create a initrd for the domU? I didnt need one when dom0 is
> 2.6.18-xen kernel.

That is perplexing. If you did not change anything in your DomU it
should work as before.
> *
> *BTW. I dont see a PARAVIRT_GUEST config option in the forward ported 2.6.32
> kernel*.

Right. You won't. They are a different type of patches.