Public bug reported:

SRU Justification

[Impact]

* Microsoft requested patches to work around intermittent deployment
failures on AMDv4 VM sizes due to issues with large values of Hyper-V
timer

[Fix]

* Questing and Noble: 
- cherry-picks of the following SAUCE patches from Microsoft 
(https://github.com/dcui/linux/tree/decui/Ubuntu-azure-6.8-6.8.0-1043.49_22.04.1-V2):
  - 28b18cb: "UBUNTU: SAUCE: clocksource: hyper-v: do not use an insanely big 
TSC in hv_read_tsc_page_tsc()"
  - f796530: "UBUNTU: SAUCE: clocksource: hyper-v: use the APIC timer if the 
Hyper-V timer is unreliable on some CPUs"
* Jammy:
- cherry-pick of the following SAUCE patch from Microsoft 
(https://github.com/dcui/linux/tree/decui/Ubuntu-azure-6.8-6.8.0-1043.49_22.04.1-V2):
  - 28b18cb: "UBUNTU: SAUCE: clocksource: hyper-v: do not use an insanely big 
TSC in hv_read_tsc_page_tsc()"
- backport of the following SAUCE patch from Microsoft 
(https://github.com/dcui/linux/tree/decui/Ubuntu-azure-6.8-6.8.0-1043.49_22.04.1-V2):
  - f796530: "UBUNTU: SAUCE: clocksource: hyper-v: use the APIC timer if the 
Hyper-V timer is unreliable on some CPUs"
- cherry-pick of the following upstream patches
  - fd0c6b0: "x86/vdso: Fix gettimeofday masking"
  - 4b52223: "clocksource: hyper-v: Provide noinstr sched_clock()"
- backports of the following upstream patches
  - 9dfb6bf: "clocksource: hyper-v: Adjust hv_read_tsc_page_tsc() to avoid 
special casing U64_MAX"
  - 47a2a14: "clocksource: hyper-v: Introduce a pointer to TSC page"

[Test Plan]

* Compile tested
* Microsoft tested

[Regression potential]

* Upstream changes are largely localized to time and clock source functions, 
and have been upstream for some time. Regression likliehood is slim.
* Possible regressions could result in unexpected behavior of Hyper-V driver.

[Other info]

* SF#00422328

** Affects: linux-azure (Ubuntu)
     Importance: Undecided
         Status: New

** Affects: linux-azure (Ubuntu Jammy)
     Importance: Undecided
         Status: New

** Affects: linux-azure (Ubuntu Noble)
     Importance: Undecided
         Status: New

** Affects: linux-azure (Ubuntu Questing)
     Importance: Undecided
         Status: New

** Affects: linux-azure (Ubuntu Resolute)
     Importance: Undecided
         Status: New


** Tags: kernel-daily-bug

** Also affects: linux-azure (Ubuntu Noble)
   Importance: Undecided
       Status: New

** Also affects: linux-azure (Ubuntu Jammy)
   Importance: Undecided
       Status: New

** Also affects: linux-azure (Ubuntu Questing)
   Importance: Undecided
       Status: New

** Also affects: linux-azure (Ubuntu Resolute)
   Importance: Undecided
       Status: New

-- 
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Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2137674

Title:
  [Azure] AMDv4 VMs may get no timer interrupts or suffer from timer
  interrupt storms

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