Xen Virtualization on Linux and Solaris

Straight forward attempt to load 2.6.34.7 kernel xenified aka Suse under Fedora’s 14 Xen 4.0.1 generates following output to console :-

Starting udev: udevd-work[591]: kernel-provided name 'pci_iomul' and NAME= 'xen/pci_iomul' disagree, please use SYMLINK+= or change the kernel to provide the proper name

udevd-work[539]: kernel-provided name 'evtchn' and NAME= 'xen/evtchn' disagree, please use SYMLINK+= or change the kernel to provide the proper name

Situation described in [1] for pvops kernel on May 26 2010 now occurs for XenLinux kernel. In case [1],[2] all pvops xen backend devices have been renamed like xen_*. To get rid of messages above it’s also possible via patch xen-backend.rules keeping kernel’s names for xen backend devices the same

--- a/tools/hotplug/Linux/xen-backend.rules	2010-10-25 00:50:07.812223772 +0400
+++ b/tools/hotplug/Linux/xen-backend.rules	2010-10-24 23:58:22.000000000 +0400
@@ -6,6 +6,8 @@
 SUBSYSTEM=="xen-backend", KERNEL=="vif-*", ACTION=="offline", RUN+="$env{script} offline"
 SUBSYSTEM=="xen-backend", KERNEL=="vscsi*", RUN+="/etc/xen/scripts/vscsi $env{ACTION}"
 SUBSYSTEM=="xen-backend", ACTION=="remove", RUN+="/etc/xen/scripts/xen-hotplug-cleanup"
-KERNEL=="evtchn", NAME="xen/%k"
+KERNEL=="evtchn", SYMLINK+="xen/%k"
 KERNEL=="blktap[0-9]*", NAME="xen/%k"
-KERNEL=="pci_iomul", NAME="xen/%k"
+KERNEL=="pci_iomul", SYMLINK+="xen/%k"
+KERNEL=="gntdev", SYMLINK+="xen/%k"
+KERNELS=="xen", KERNEL=="xvd*", SUBSYSTEM=="block", OPTIONS+="last_rule"

Download from the Net xen-4.0.1-6.fc14.src.rpm and install it. Add patch above as udev-rules.patch to /root/rpmbuild/SOURCES
folder and update /root/rpmbuild/SPECS/xen.spec correspondently to process this patch. Install ( or update) Xen 4.0.1 on F14 via

yum install xen-4.0.1-7.fc14.x86_64.rpm \
xen-debuginfo-4.0.1-7.fc14.x86_64.rpm \
xen-devel-4.0.1-7.fc14.x86_64.rpm \
xen-doc-4.0.1-7.fc14.x86_64.rpm \
xen-hypervisor-4.0.1-7.fc14.x86_64.rpm \
xen-libs-4.0.1-7.fc14.x86_64.rpm \
xen-licenses-4.0.1-7.fc14.x86_64.rpm \
xen-runtime-4.0.1-7.fc14.x86_64.rpm

Build 2.6.34.7 xenified aka Suse kernel. Download Andrew Lyon’s rebased patches set V.5 (2.6.34)

# cd /usr/src/xenLinux/
# wget http://gentoo-xen-kernel.googlecode.com/files/xen-patches-2.6.34-5.tar.bz2

Untar linux-2.6.34.7.tar.bz2 and apply patches.

# cd /usr/src/xenLinux/
# bzcat linux-2.6.34.7.tar.bz2 | tar xf -
# mkdir -p xen-patches-2.6.34-5
# cd xen-patches-2.6.34-5
# bzcat ../xen-patches-2.6.34-5.tar.bz2 | tar xf -
# cd ../linux-2.6.34.7

Run script

#!/bin/bash
for P in `ls ../xen-patches-2.6.34-5/6*.patch1 | sort `
do
patch -p1 -s -i $P
if [ $? = 0 ]; then
echo $P applied
else
echo "Error processing "$P
exit 1
fi
done

Build kernel :-

# make menuconfig
# make -j(x)(number_of_cores)
# make modules_install install
# dracut -f /boot/initramfs-2.6.34.7-0.5-xen.img 2.6.34.7-0.5-xen







Get .config file for x86_64

Modify /etc/rc.local as follows

#!/bin/sh
#
# This script will be executed *after* all the other init scripts.
# You can put your own initialization stuff in here if you don't
# want to do the full Sys V style init stuff.

if (uname -r |grep 2.6.34.7-0.5-xen) ; then
modprobe evtchn
modprobe blktap
modprobe blkbk
modprobe xenblk
modprobe netbk
modprobe gntdev
modprobe usbbk
fi
touch /var/lock/subsys/local

Setup Libvirt 0.8.3 :-

# yum install virtinst python-virtinst libvirt \
libvirt-python virt-viewer virt-manager

Reboot into Xen Environment :-

title Xen 4.0.1 Fedora (2.6.34.7-0.5-xen) (/dev/sda9)
root (hd0,8)
kernel /xen.gz dom0_mem=1024M
module /vmlinuz-2.6.34.7-0.5-xen ro root=/dev/mapper/vg_fedora14-lv_root LANG=US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us
module /initramfs-2.6.34.7-0.5-xen.img

Verify environment :-

[root@fedora14 ~]# ls -l /dev/xen
total 0
lrwxrwxrwx 1 root root 9 Oct 25 17:48 evtchn -> ../evtchn
lrwxrwxrwx 1 root root 9 Oct 25 17:48 gntdev -> ../gntdev
lrwxrwxrwx 1 root root 12 Oct 25 17:48 pci_iomul -> ../pci_iomul

[root@fedora14 ~]# xm info
host : fedora14
release : 2.6.34.7-0.5-xen
version : #3 SMP Mon Oct 25 13:29:54 MSD 2010
machine : x86_64
nr_cpus : 4
nr_nodes : 1
cores_per_socket : 4
threads_per_core : 1
cpu_mhz : 2833
hw_caps : bfebfbff:20100800:00000000:00000940:0008e3fd:00000000:00000001:00000000
virt_caps : hvm
total_memory : 8190
free_memory : 7083
node_to_cpu : node0:0-3
node_to_memory : node0:7083
node_to_dma32_mem : node0:3259
max_node_id : 0
xen_major : 4
xen_minor : 0
xen_extra : .1
xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xffff800000000000
xen_changeset : unavailable
xen_commandline : dom0_mem=1024M
cc_compiler : gcc version 4.5.1 20100924 (Red Hat 4.5.1-4) (GCC)
cc_compile_by : root
cc_compile_domain :
cc_compile_date : Mon Oct 25 12:12:09 MSD 2010
xend_config_format : 4

[root@fedora14 ~]# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.90e6ba2d11eb no eth0
virbr0 8000.000000000000 yes




References
1.http://lists.xensource.com/archives/html/xen-devel/2010-05/msg01310.html
2.http://lists.xensource.com/archives/html/xen-devel/2010-05/msg01379.html

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