Comment 0 for bug 1913294

[Impact]

To include the missing upstream patches to the 4.15 and 5.4 kernel.

* x86/entry/64: Do not use RDPID in paranoid entry to accommodate KVM:
- occasional random failure when running KVM
* x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task
- Google folks found this when running their fuzzy test cases. Don't know how realistic this can hit.
* x86/fsgsbase: Fix Xen PV support
* x86/process/64: Make save_fsgs_for_kvm() ready for FSGSBASE
- these two are for VMMs.

(Some of those are already included in our azure kernels)

[Test Case]

Since we are syncing with mainline a boot test and a regression test in ACC instances should be enough to confirm the changes are working.

Since these instances are not publicly available yet, Msft is helping us to test this changes.

[Where problems could occur]

This affects the SGX driver that is only available on ACC instances (which is not widely used yet).