Re: [Xen-users] usage questions for GRUB2 chainloader workaround when booting Xen 4.5 on UEFI

[Carlos Gustavo Ramirez Rodriguez <carlosgrr@xxxxxxxxx>]

Hello, lyndat3

> I'm setting up Xen 4.5 on linux/64.

I'm trying this too, :)

From my perspective, unfortunately the citrix guys are monday-friday answering only and it can be quite frustrating to wait a whole weekend to work on these projects, unless offcourse if that's your time frame.

> The system's booted GRUB2+EFI.
>
> Reading
>
> Â Â Â Â https://wiki.gentoo.org/wiki/GRUB2/Chainloading
>
> booting Xen from GRUB2 needs, for now - until Xen 4.5 , a chainloader workaround; example:
>
> Â Â Â Â menuentry 'Xen EFI' {
> Â Â Â Â Â Â Â Â insmod part_gpt
> Â Â Â Â Â Â Â Â insmod search_fs_uuid
> Â Â Â Â Â Â Â Â insmod chain
> Â Â Â Â Â Â Â Â chainloader (hd0,gpt1)/EFI/XEN/xen.efi
> Â Â Â Â }
>
> On my system, Xen pacakges install
>
> Â Â Â Â find / | egrep "xen.*\.efiquot;
> Â Â Â Â Â Â Â Â /usr/lib64/efi/xen.efi
> Â Â Â Â Â Â Â Â /usr/lib64/efi/xen-4.efi
> Â Â Â Â Â Â Â Â /usr/lib64/efi/xen-4.5.0_03-359.efi
> Â Â Â Â Â Â Â Â /usr/lib64/efi/xen-4.5.efi
>
> (1) Is
>
> Â Â Â Â cp /usr/lib64/efi/xen.efi /<path>/<to>/EFI/XEN/xen.efi
>
> correct for use in the chainloader stanza?
>

I have md5sum'ed all of those files and even vimdiff'ed them, I am pretty sure they are exactly the same file with just a different name, so YES, that's the way to do it, just CP any of those files as stated.

> (2) IIUC, since the Xen pkgs are not installing xen.efi on the EFI partion, at every Xen upgrade the xen.efi has to be re-copied. Correct? Shouldn't pkgs install the .efi on the UEFI system partition?
>

Reading throught the INSTALL file from the root folder of the xen source, you can read this excerpt:

"
Examples
========
* To build a private copy of tools and xen:
configure --prefix=/odd/path --sysconfdir=/odd/path/etc --enable-rpath
make
sudo make install BOOT_DIR=/ood/path/boot EFI_DIR=/odd/path/efi
"

Which will build you an EFI file at the exact spot you want It to be. I am not sure why they have trailed this path, but probably because of different folder schemes and conflicting use cases.

> (3) on a multi-disk system, "(hd0,gpt1)" can be vague.
>
> Can the chainloader stanza use a definite UUID device spec instead?
>
> On my system, with
>
> Â Â Â Â mount | grep efi | grep ^/dev
> Â Â Â Â Â Â Â Â /dev/sdg2 on /boot/efi type vfat (rw,relatime,fmask=0002,dmask=0002,allow_utime=0020,codepage=437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro)
>
> Â Â Â Â blkid /dev/sdg2 -s UUID
> Â Â Â Â Â Â Â Â /dev/sdg2: UUID="94C3-29F3"
>
> Would this GRUB2 menuentry work?
>
> Â Â Â Â menuentry 'Xen EFI' {
> Â Â Â Â Â Â Â Â insmod part_gpt
> Â Â Â Â Â Â Â Â insmod search_fs_uuid
> Â Â Â Â Â Â Â Â insmod chain
> Â Â Â Â Â Â Â Â search --no-floppy --fs-uuid 94C3-29F3
> Â Â Â Â Â Â Â Â chainloader /EFI/XEN/xen.efi
> Â Â Â Â }
>
> LT
>

My chainloading/linux skills are probably way behind yours, but you should try that, it appear to be well referenced from great websites and the worst thing that would happen is that you restarted a production server that shouldn't be stopped, but on the bright side, from the grub2 entry you can try to F2 and test these commands to see if they work, and change them until you have found a working command set, just restarting the computer in-between trials.

I am not an employee from citrix or in anyway related to the dev team or companies that support this awesome hypervisor, I written this e-mail with a big smile in my face for being able to try and help you, also any jokes I have made aren't supposed to decrease your level of responsabilities during those procedures.

If anyone else can correct me, please do it, also, Lyndat3, reply if I have been of assistance or not...

--
Gustavo

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