[SRU][N:gcp-6.14/P:gcp][PATCH 0/2] Fix attestation failure due to vTPM device error

[Tim Whisonant]

BugLink: https://bugs.launchpad.net/bugs/2116287

SRU Justification:

[Impact]

UBUNTU: SAUCE: Revert "x86/mtrr: Rename mtrr_overwrite_state() to guest_force_mtrr_state()"

This reverts commit 6a5abeea9c72e1d2c538622b4cf66c80cc816fd3.

Google requests that this commit be removed from 6.14 kernels,
namely plucky:linux-gcp and noble:linux-gcp-6.14. This commit
along with 8e690b817e38769dc2fa0e7473e5a5dc1fc25795
("x86/kvm: Override default caching mode for SEV-SNP and TDX")
are responsible for a TPM failure encountered on their TDX-enabled
deployments. When present, error message "TPM fail - No TPM chip
found" is observed during boot and the TPM is not available.

UBUNTU: SAUCE: Revert "x86/kvm: Override default caching mode for SEV-SNP and TDX"

This reverts commit 8e690b817e38769dc2fa0e7473e5a5dc1fc25795.

Google requests that this commit be removed from 6.14 kernels,
namely plucky:linux-gcp and noble:linux-gcp-6.14. This commit
along with 6a5abeea9c72e1d2c538622b4cf66c80cc816fd3
("x86/mtrr: Rename mtrr_overwrite_state() to guest_force_mtrr_state()")
are responsible for a TPM failure encountered on their TDX-enabled
deployments. When present, error message "TPM fail - No TPM chip
found" is observed during boot and the TPM is not available.

[Fix]

Plucky:gcp     revert upstream commits
Noble:gcp-6.14 revert upstream commits

[Test Plan]

Compile and boot tested.

[Where problems could occur]

This change is considered low risk as the commits were cleanly
reverted, and the resulting kernel has been verified to resolve
the issue both internally and by Google.

Tim Whisonant (2):
  UBUNTU: SAUCE: Revert "x86/mtrr: Rename mtrr_overwrite_state() to
    guest_force_mtrr_state()"
  UBUNTU: SAUCE: Revert "x86/kvm: Override default caching mode for
    SEV-SNP and TDX"

 arch/x86/hyperv/ivm.c              |  2 +-
 arch/x86/include/asm/mtrr.h        | 10 +++++-----
 arch/x86/kernel/cpu/mtrr/generic.c |  6 +++---
 arch/x86/kernel/cpu/mtrr/mtrr.c    |  2 +-
 arch/x86/kernel/kvm.c              |  4 ----
 arch/x86/xen/enlighten_pv.c        |  4 ++--
 6 files changed, 12 insertions(+), 16 deletions(-)

-- 
2.43.0