Bug 753480

Do you have any xen kernels installed? Which files do you have in /boot ?

Here's a bit more information about the system:

[root@vmhost ~]# uname -a
Linux vmhost 3.1.1-1.fc16.i686 #1 SMP Fri Nov 11 22:23:53 UTC 2011 i686 i686 i386 GNU/Linux

[root@vmhost ~]# rpm -qa|grep ^kernel
kernel-3.1.0-7.fc16.i686
kernel-3.1.1-1.fc16.i686

[root@vmhost ~]# rpm -qa|grep ^xen
xen-libs-4.1.2-1.fc16.i686
xen-4.1.2-1.fc16.i686
xen-licenses-4.1.2-1.fc16.i686
xen-runtime-4.1.2-1.fc16.i686
xen-hypervisor-4.1.2-1.fc16.i686

[root@vmhost ~]# ls /boot/
config-3.1.0-7.fc16.i686         memtest86+-4.20
config-3.1.1-1.fc16.i686         System.map-3.1.0-7.fc16.i686
efi                              System.map-3.1.1-1.fc16.i686
elf-memtest86+-4.20              vmlinuz-3.1.0-7.fc16.i686
grub                             vmlinuz-3.1.1-1.fc16.i686
grub2                            xen-4.1.2.gz
initramfs-3.1.0-7.fc16.i686.img  xen-4.1.gz
initramfs-3.1.1-1.fc16.i686.img  xen.gz
lost+found                       xen-syms-4.1.2
-----

Thanks much.

Please try to edit /etc/grub.d/20_linux_xen and insert a 'set -x' line near the top and run 'grub2-mkconfig 2> log' and attach the log.

$ cat log 
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-3.1.1-1.fc16.i686
Found initrd image: /boot/initramfs-3.1.1-1.fc16.i686.img
Found linux image: /boot/vmlinuz-3.1.0-7.fc16.i686
Found initrd image: /boot/initramfs-3.1.0-7.fc16.i686.img
+ prefix=/usr
+ exec_prefix=/usr
+ bindir=/usr/bin
+ libdir=/usr/lib
+ . /usr/lib/grub/grub-mkconfig_lib
++ transform='s&^&&;s,grub,grub2,'
++ prefix=/usr
++ exec_prefix=/usr
++ datarootdir=/usr/share
++ datadir=/usr/share
++ bindir=/usr/bin
++ sbindir=/sbin
+++ echo grub
+++ sed 's&^&&;s,grub,grub2,'
++ pkgdatadir=/usr/share/grub2
++ test x = x
+++ echo grub-probe
+++ sed 's&^&&;s,grub,grub2,'
++ grub_probe=/sbin/grub2-probe
++ test x = x
+++ echo grub-mkrelpath
+++ sed 's&^&&;s,grub,grub2,'
++ grub_mkrelpath=/usr/bin/grub2-mkrelpath
+++ which gettext
++ gettext=gettext
+ export TEXTDOMAIN=grub
+ TEXTDOMAIN=grub
+ export TEXTDOMAINDIR=/usr/share/locale
+ TEXTDOMAINDIR=/usr/share/locale
+ CLASS='--class gnu-linux --class gnu --class os --class xen'
+ '[' xFedora = x ']'
+ OS='Fedora Linux'
++ echo Fedora
++ cut '-d ' -f1
++ tr A-Z a-z
+ CLASS='--class fedora --class gnu-linux --class gnu --class os --class xen'
+ case ${GRUB_DEVICE} in
+ '[' x46fe9463-2887-4175-8f41-0c93ae10c897 = x ']'
+ '[' x = xtrue ']'
+ test -e /dev/disk/by-uuid/46fe9463-2887-4175-8f41-0c93ae10c897
+ uses_abstraction /dev/mapper/vg_vmhost-lv_root lvm
+ device=/dev/mapper/vg_vmhost-lv_root
++ /sbin/grub2-probe --device /dev/mapper/vg_vmhost-lv_root --target=abstraction
+ abstraction='lvm '
+ for module in '${abstraction}'
+ test xlvm = xlvm
+ return 0
+ LINUX_ROOT_DEVICE=/dev/mapper/vg_vmhost-lv_root
++ /sbin/grub2-probe --device /dev/mapper/vg_vmhost-lv_root --target=fs
+ '[' xext2 = xbtrfs ']'
++ for i in '/boot/vmlinu[xz]-*' '/vmlinu[xz]-*' '/boot/kernel-*'
++ grub_file_is_not_garbage /boot/vmlinuz-3.1.0-7.fc16.i686
++ test -f /boot/vmlinuz-3.1.0-7.fc16.i686
++ case "$1" in
++ return 0
+++ basename /boot/vmlinuz-3.1.0-7.fc16.i686
++ basename=vmlinuz-3.1.0-7.fc16.i686
+++ echo vmlinuz-3.1.0-7.fc16.i686
+++ sed -e 's,^[^0-9]*-,,g'
++ version=3.1.0-7.fc16.i686
+++ dirname /boot/vmlinuz-3.1.0-7.fc16.i686
++ dirname=/boot
++ config=
++ for j in '"${dirname}/config-${version}"' '"${dirname}/config-${alt_version}"' '"/etc/kernels/kernel-config-${version}"'
++ test -e /boot/config-3.1.0-7.fc16.i686
++ config=/boot/config-3.1.0-7.fc16.i686
++ break
++ grep -qx CONFIG_XEN_DOM0=y /boot/config-3.1.0-7.fc16.i686
++ grep -qx CONFIG_XEN_PRIVILEGED_GUEST=y /boot/config-3.1.0-7.fc16.i686
++ for i in '/boot/vmlinu[xz]-*' '/vmlinu[xz]-*' '/boot/kernel-*'
++ grub_file_is_not_garbage /boot/vmlinuz-3.1.1-1.fc16.i686
++ test -f /boot/vmlinuz-3.1.1-1.fc16.i686
++ case "$1" in
++ return 0
+++ basename /boot/vmlinuz-3.1.1-1.fc16.i686
++ basename=vmlinuz-3.1.1-1.fc16.i686
+++ echo vmlinuz-3.1.1-1.fc16.i686
+++ sed -e 's,^[^0-9]*-,,g'
++ version=3.1.1-1.fc16.i686
+++ dirname /boot/vmlinuz-3.1.1-1.fc16.i686
++ dirname=/boot
++ config=
++ for j in '"${dirname}/config-${version}"' '"${dirname}/config-${alt_version}"' '"/etc/kernels/kernel-config-${version}"'
++ test -e /boot/config-3.1.1-1.fc16.i686
++ config=/boot/config-3.1.1-1.fc16.i686
++ break
++ grep -qx CONFIG_XEN_DOM0=y /boot/config-3.1.1-1.fc16.i686
++ grep -qx CONFIG_XEN_PRIVILEGED_GUEST=y /boot/config-3.1.1-1.fc16.i686
++ for i in '/boot/vmlinu[xz]-*' '/vmlinu[xz]-*' '/boot/kernel-*'
++ grub_file_is_not_garbage '/vmlinu[xz]-*'
++ test -f '/vmlinu[xz]-*'
++ return 1
++ for i in '/boot/vmlinu[xz]-*' '/vmlinu[xz]-*' '/boot/kernel-*'
++ grub_file_is_not_garbage '/boot/kernel-*'
++ test -f '/boot/kernel-*'
++ return 1
+ linux_list=
+ '[' x = x ']'
+ exit 0
done

There is no CONFIG_XEN_DOM0=y in /boot/config-3.1.0-7.fc16.i686.

Try to install kernel-PAE and you will find it set in config-3.1.0-7.fc16.i686.PAE and then grub2-mkconfig will create the entries.

I guess it is OK (and perhaps necessary) that XEN haven't been enabled in the non-PAE kernel. So I guess that if there is anything left here then it is a Xen documentation issue. Reassigning.

Installing kernel-PAE and re-running "grub2-mkconfig -o /boot/grub2/grub.cfg" creates the needed entries.  Thanks much!

Yes, you need to use kernel-PAE as the dom0 kernel for i686, as non-PAE support was dropped in xen some time ago.