Fix QEMU/KVM support for EPT paging level 4/5

[Thibf]

This is a public version of:
- https://bugs.launchpad.net/bugs/2055747
- https://bugs.launchpad.net/bugs/2058092

[ Impact ]

 * Fix EPT paging level 4 using incorrectly memory range in specific configuration.
 * Expose support of EPT paging level 5 for compatible hardware (e.g. Sierra Forest).

[ Fix ]

Clean cherry pick for the fix and associated self-tests.

[ Test Plan ]

On compatible hardware
 * Verify level 5 flag
 * Execute self-tests

[ Where problems could occur ]

 * Regression in KVM features.

[ Other info ]

Context:
https://lore<email address hidden>/
https://lore<email address hidden>/

[Thibf (thibf)]

Patch submitted: https://lists.ubuntu.com/archives/kernel-team/2024-July/151971.html

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-intel/6.8.0-1009.16 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-intel' to 'verification-done-noble-linux-intel'. If the problem still exists, change the tag 'verification-needed-noble-linux-intel' to 'verification-failed-noble-linux-intel'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-ibm-gt-tdx/6.8.0-1009.10+tdx1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-ibm-gt-tdx' to 'verification-done-noble-linux-ibm-gt-tdx'. If the problem still exists, change the tag 'verification-needed-noble-linux-ibm-gt-tdx' to 'verification-failed-noble-linux-ibm-gt-tdx'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!