[TDX] Support Kexec/Kdump

[Thibf]

[ Impact ]

Kexec is currently disabled on linux-intel as it was incompatible with tdx.
These patch make it possible to use it at the same time than TDX

[ Fix ]

A backport of the kexec enablement for tdx on 6.8 has been done by intel.

[ Test Plan ]

Use kexec to do a kdump on hardware support tdx.
It was tested by Intel and me on dedicated hardware.

[ Where problems could occur ]

Regression on TDX/Kexec related features.

[Thibf (thibf)]

Submitted to the mailing list : https://lists.ubuntu.com/archives/kernel-team/2024-June/151814.html

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

This bug is awaiting verification that the linux-ibm-gt-tdx/6.8.0-1002.4 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!

[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!