xen, efi, mdraid, grub2

[hydrapolic]

We have an amd64 machine (Intel DH87MC, Core i7) that is able to boot EFI and we want to run Xen hypervisor (dom0) on it. We have 2 disks with 1TB space and we would like raid1 for redundancy. The hypervisor is placed on a partition without LVM. We want to boot XEN by default.

p1 - boot - 500MB (efi boot space)
p2 - root - 10GB
p3 - LVM for the rest (domU)

# we create the partitions, then the raid devices and we format them
parted /dev/sda
mklabel gpt
mkpart ESI fat32 0% 500m
mkpart primary ext4 500m 10500m
mkpart primary ext4 10500m 100%
set 1 boot on
set 3 lvm on
quit

[the same with /dev/sdb]

mdadm --create --verbose /dev/md1 --level=1 --raid-devices=2 --metadata=0.90 /dev/sda1 /dev/sdb1
mdadm --create --verbose /dev/md2 --level=1 --raid-devices=2 --metadata=0.90 /dev/sda2 /dev/sdb2
mdadm --create --verbose /dev/md3 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3

mkfs.vfat -F 32 /dev/md1
mkfs.ext4 /dev/md2
pvcreate /dev/md3

# mount in the livecd environment
mount /dev/md2 /mnt/gentoo
mkdir /mnt/gentoo/boot
mount /dev/md1 /mnt/gentoo/boot

# xen 4.2.2 in testing, grub 2 also in testing
echo 'app-emulation/xen' >> /etc/portage/package.keywords
echo 'sys-boot/grub' >> /etc/portage/package.keywords
echo 'sys-boot/efibootmgr' >> /etc/portage/package.keywords

# efi USE flag because without it, the installation failed because it was
# unable to create the symlinks.
echo 'app-emulation/xen efi' >> /etc/portage/package.use
echo 'sys-devel/binutils multitarget' >> /etc/portage/package.use

echo 'GRUB_PLATFORMS="efi-64 pc"' >> /etc/portage/make.conf
emerge -av sys-boot/grub:2 sys-fs/mdadm sys-fs/lvm2 app-emulation/xen ...

[compile kernel, install modules]

# grub2-mkconfig uses the kernel names to create boot entries, the configuration
# file is needed to create the Xen entries
cp arch/x86/boot/bzImage /boot/kernel-3.9.8-xen
cp .config /boot/config-3.9.8-xen

# we want to boot Xen by default, let the kernel to assemble md1 and md2 and we limit
# the dom0 memory limit
modify /etc/default/grub:
GRUB_DEFAULT="saved"
GRUB_CMDLINE_LINUX="md=1,/dev/sda1,/dev/sdb1 md=2,/dev/sda2,/dev/sdb2"
GRUB_CMDLINE_XEN="dom0_mem=4G"

# grub2-install creates a gentoo directory with grubx64.efi, however boot/bootx64.efi is the default
# for amd64 (http://en.wikipedia.org/wiki/Extensible_Firmware_Interface)
mkdir -p /boot/efi/boot
grub2-install --target=x86_64-efi --efi-directory=/boot
mv /boot/efi/gentoo/grubx64.efi /boot/efi/boot/bootx64.efi
rm -rf /boot/efi/gentoo

# this creates the configuration with Xen entries
grub2-mkconfig -o /boot/grub2/grub.cfg

# check the entries and pick Xen
grep ^menuentry /boot/grub/grub.cfg | cut -f2 -d"'"
grub2-set-default "Gentoo GNU/Linux, with Xen hypervisor"

# xen created /boot/efi/gentoo/xen-4.2.2.efi, we don't need it
rm -rf /boot/efi/gentoo

# under /boot we have:
config-3.9.8-xen (kernel config)
efi (contains /boot/efi/boot/bootx64.efi - starts grub2)
grub2 (contains grub.cfg, grubenv, x86_64-efi, etc.)
kernel-3.9.8-xen (kernel)
xen-4.2.2.gz (the following created by app-emulation/xen)
xen-4.2.gz
xen-4.gz
xen-syms-4.2.2
xen.gz

[Clad in Sky]

Thanks, I guess that will help with getting Gentoo installed on an UEFI laptop.

I've read "mkpart esi ..." before (Wiki.gentoo.org) and just assumed it was a typo.
What does ESI do? man parted and info parted don't show ESI as valid argument for mkpart.
_________________
Kali Ma
Now it's autumn of the aeons
Dance with your sword
Now it's time for the harvest

[hydrapolic]

I took that over from https://wiki.gentoo.org/wiki/UEFI_Gentoo_Quick_Install_Guide and to be honest, I didn't check the man pages before testing this out. You are right, I cannot find any reference to it either (nothing on duckduckgo or google).

I'll be doing a research soon because I need to setup a similar configuration so if I find out what that means (or what the absence of it breaks), I'll post a note here.

Thanks again for pointing that out.

[Razzle]

I use a similar setup, however the dom0 fails to detect ACPI properly. This causes the system to boot with only 1 CPU and other problems. I haven't found a solution yet but the Xen guide suggests using the xen efi bootloader instead of grub, which I haven't had time to test yet.
Does ACPI work for you?

[hydrapolic]

Hello Razzle, I haven't played with ACPI in any way, but all of the CPUs are detected correctly. By "ACPI working" you mean power saving?

Regarding ACPI in dmesg