[Fedora-xen] Xen-kernel with no PAE support

[Chris Lalancette]

Filipe Miranda wrote:
> Hello,
> 
> Since I have a thinkpad T41 with a non PAE CPU, unfortunately the
> xen-kernel that comes with the FC6 does not work.
> I know that the upstreams of the xen-kernel for FC6 will only work on
> CPUs with PAE support, but what would be the best way to have a
> xen-kernel what would have no-PAE support?
> 
> I downloaded the src xen-kernel file from the FC6 repositories and tried
> to disable the PAE support. No success, it seems that the xen itself is
> PAE aware.
> 
> Is there any *smart* suggestion on how to  compile or get a xen-kernel
> that would work on a non-PAE CPU?
> 
> Regards,
> 
> -- 
> ---
> Filipe T Miranda
> 
> 
> ------------------------------------------------------------------------
> 
> --
> Fedora-xen mailing list
> Fedora-xen at redhat.com
> https://www.redhat.com/mailman/listinfo/fedora-xen

Filipe,
     You have two options:

1)  Use an FC5 -xen0 kernel; those didn't have PAE enabled.  However, that also means that your guests have to use the FC5 -xenU kernels, which also don't have PAE enabled.

2)  Recompile both the hypervisor and the -xen kernel on FC6 to remove PAE support.  The problem with this approach is that all of the FC6 guest kernels have PAE enabled, so you won't be able to use any of the normal tools (virt-install, virt-manager, etc) to install the guests without some effort.

If you want to do 2), you basically have to:
a) install FC6 kernel src RPM.
b) rpmbuild -bp kernel-2.6.spec
c) cd BUILD/kernel-2.6.18/xen
d) make verbose=y crash_debug=y
e) cp xen.gz /boot
f) cd BUILD/kernel-2.6.18/linux-2.6.18
g) make menuconfig -> set to NOHIGHMEM
h) make
i) make modules_install
j) make install

And then setup your grub.conf to point to the right hypervisor/kernel.  Note that all of the above is from memory and not tested; it's just approximately what you have to do.

No, it's not pretty.

Chris Lalancette