Re: A bit off topic.. converting Linux HVM to PV

[Brad Spencer <brad%anduin.eldar.org@localhost>]

   On 07.10.2010 22:39, Brad Spencer wrote:
   >>> I think I managed to build a Linux kernel with Xen guest support.  It
   >>> claims the following upon trying to 'xm create -c ...':
   >>
   >> How did you create it?
   > 
   > Probably badly...  basically...
   > 
   > cd /usr/src/linux
   > make menuconfig
   > Select all of the Xen guest packages and bits and exit
   > make clean
   > make vmlinux
   > 
   > After the build, copy vmlinux to the place I hold PV kernels and try to
   > use it.
   > 
   >> Was it configured to use a ramdisk? What fs are compiled in/modularized?
   > 
   > I have to admit I don't know how to tell if it is using a ramdisk??  For
   > fs support, at first it just had romfs, but I did edit .config and added
   > all of the ext-foo filesystems and rebuilt.  Didn't help.

   There's a wiki page on XenSource if you want to build from the git repo.

   http://wiki.xensource.com/xenwiki/XenParavirtOps

   For ramdisk (initrd), see the dom0 build commands at the end of the
   page. You pass the rd as an option in the domU configuration file:

   kernel = "/boot/vmlinux-2.6.31-domU"
   ramdisk = "/boot/initrd.gz"

   -- 
   Jean-Yves Migeon
   jeanyves.migeon%free.fr@localhost


Thanks.  That was all quite helpful, but I was still unable to get a fully
PV Linux working.  I did get a ramdisk built with that I thought was
needed, but I end up with this:

.
.
NET: Registered protocol family 17
registered taskstats version 1
XENBUS: Device with no driver: device/console/0
Freeing unused kernel memory: 672k freed
Write protecting the kernel read-only data: 8192k
Freeing unused kernel memory: 996k freed
Freeing unused kernel memory: 388k freed
mount: mounting /dev/xvda1 on /mnt failed: Invalid argument
ERROR:  No /sbin/init found on rootdev (or not mounted).  Trouble ahead.
        You can try to fix it. Type 'exit' when things are done.
#

Something is obviously not included in the RD image and/or kernel I am
booting.  Although, I have tried building kernels with the supported
filesystems and have tried making RD images with the supported modules.
Although it is pretty hard to tell if you have succeeded in ever doing
that.  The odd thing is that 'od -c /dev/xvda1' does return pages and
pages of stuff at the above prompt, so it would seem like the device is
attached.  However, 'mount -t ext4 /dev/xvda1 /mnt' returns an error
simular to the one above, although ext4 should be available as a usable
FS, either built in or as a module [depending on which kernel I used].

This will have to be put on the back burner for now.  Simply no more time
to work on this.  NetBSD is soo much simpler about all of this.....


Thanks for your all of your help.



-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS
http://anduin.eldar.org  - & -  http://anduin.ipv6.eldar.org [IPv6 only]