[PATCH v1 3/3] x86/tdx: Provide stub tdx_accept_memory() for non-TDX configs

When CONFIG_INTEL_TDX_GUEST is not defined but CONFIG_UNACCEPTED_MEMORY=y is,
the kernel fails to link with an undefined reference to tdx_accept_memory from
arch_accept_memory. Provide a stub for tdx_accept_memory to fix the build for
that configuration.

CONFIG_UNACCEPTED_MEMORY is also selected by CONFIG_AMD_MEM_ENCRYPT, and there
are stubs for snp_accept_memory for when it is not defined. Previously this did
not result in an error when CONFIG_INTEL_TDX_GUEST was not defined because the
branch that references tdx_accept_memory() was being discarded due to
DISABLE_TDX_GUEST being set.

Cc: <redacted> # v6.5+
Fixes: 75d090fd167a ("x86/tdx: Add unaccepted memory support")
Signed-off-by: Jeremi Piotrowski <redacted>
---
 arch/x86/include/asm/shared/tdx.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h
index 7513b3bb69b7..58cdbaac3d5b 100644
--- a/arch/x86/include/asm/shared/tdx.h
+++ b/arch/x86/include/asm/shared/tdx.h

@@ -91,7 +91,11 @@ struct tdx_module_output {
 u64 __tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
 		      struct tdx_module_output *out);
 
+#ifdef CONFIG_INTEL_TDX_GUEST
 bool tdx_accept_memory(phys_addr_t start, phys_addr_t end);
+#else
+static inline bool tdx_accept_memory(phys_addr_t start, phys_addr_t end) { return false; }
+#endif
 
 /*
  * The TDG.VP.VMCALL-Instruction-execution sub-functions are defined

-- 
2.39.2