[SRU][N:linux-gcp/O:linux-gcp][PATCH 0/2] Fix HLT logic execution for TDX VMs

[Ian Whitfield]

BugLink: https://bugs.launchpad.net/bugs/2112602

[Impact]
Google has requested a backport of the following commits:
22cc5ca5de52 ("x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT")
9f98a4f4e721 ("x86/tdx: Fix arch_safe_halt() execution for TDX VMs")
Targets include 6.8 onwards.

[Fix]
Noble required both patches, Oracular required just the first patch. Kernels
after Oracular have already received these patches via stable updates.

Upstream stable backports were used for both patches, and these applied cleanly.

[Test plan]
Compile and boot test. Verification on Google's side is optional as this is a
fairly isolated backport.

[Where problems could occur]
This fix affects TDX guest VMs which call the HLT instruction. An issue with
this fix would be visible to the user as unexpected #VEs (virtualization
exceptions) or unexpected interrupt behavior in their TDX guest VM.

[Other]
SF #00412211

Kirill A. Shutemov (1):
  x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT

Vishal Annapurve (1):
  x86/tdx: Fix arch_safe_halt() execution for TDX VMs

 arch/x86/Kconfig                      |  1 +
 arch/x86/coco/tdx/tdx.c               | 26 ++++++++++++++++-
 arch/x86/include/asm/irqflags.h       | 40 +++++++++++++++------------
 arch/x86/include/asm/paravirt.h       | 20 +++++++-------
 arch/x86/include/asm/paravirt_types.h |  3 +-
 arch/x86/include/asm/tdx.h            |  4 +--
 arch/x86/kernel/paravirt.c            | 14 ++++++----
 arch/x86/kernel/process.c             |  2 +-
 8 files changed, 70 insertions(+), 40 deletions(-)

-- 
2.43.0