[SRU][N:gcp-6.14][PATCH 2/2] UBUNTU: SAUCE: Revert "x86/kvm: Override default caching mode for SEV-SNP and TDX"

[Tim Whisonant]

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

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.

(revert commit 8e690b817e38769dc2fa0e7473e5a5dc1fc25795)
Signed-off-by: Tim Whisonant <tim.whisonant at canonical.com>
---
 arch/x86/kernel/kvm.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 21e9e4845354..263f8aed4e2c 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -37,7 +37,6 @@
 #include <asm/apic.h>
 #include <asm/apicdef.h>
 #include <asm/hypervisor.h>
-#include <asm/mtrr.h>
 #include <asm/tlb.h>
 #include <asm/cpuidle_haltpoll.h>
 #include <asm/ptrace.h>
@@ -981,9 +980,6 @@ static void __init kvm_init_platform(void)
 	}
 	kvmclock_init();
 	x86_platform.apic_post_init = kvm_apic_init;
-
-	/* Set WB as the default cache mode for SEV-SNP and TDX */
-	mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK);
 }
 
 #if defined(CONFIG_AMD_MEM_ENCRYPT)
-- 
2.43.0