installer: Remove Xen from the bootstrap.

Description

OpenXT installer, legacy or not, is currently not using any Xen feature.

The historical reason of booting Tboot+Xen in the Legacy installer was to ensure, before running the installer and risk loosing data, to make sure that OpenXT (XenClient) would be able to run at least Tboot+Xen.

This is a bit inaccurate, as other factors can come in the way of OpenXT running smoothly. More so with the UEFI support, the installer and OpenXT installation now follow quite different bootstrap path.

Nowdays, Xen would be used as a dependency of blktap{2,3} (OXT-1378) to install images that would need their VHDs to be created by the installer.
The UEFI case has revealed some platform quirks that can be worked around by the installer running without Xen (OXT-1377), not impacting compatible platforms either.

Having a small and simple installer could also make the current OTA upgrade scheme (installer part2) less of a hassle by having a "live" upgrade image on which to reboot, perform upgrade and forward sealing on a rootfs that is not the previous version (on which the "new" script have to be retro-compatible), avoiding some other caveats at the same time.

Validation Steps

  1. Installation with measurement works in the BIOS Legacy case

  2. Installation with measurement works in the UEFI case

  3. Installation can be ran with ISO (hybrid) and PXE configuration setups

  4. OTA upgrade is available from http(s) repository

  5. Forward sealing is performed during a valid OTA upgrade

Assignee

Rich Persaud

Reporter

Eric Chanudet

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Components

Fix versions

Priority

Critical
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