KVM: arm64: Choose hyp symbol based on context

Make CHOOSE_HYP_SYM select the symbol of the active hypervisor for the
host, the nVHE symbol for nVHE and the VHE symbol for VHE. The nVHE and
VHE hypervisors see their own symbols without prefixes and trigger a
link error when trying to use a symbol of the other hypervisor.
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: David Brazdil <dbrazdil@google.com>
Link: https://lore.kernel.org/r/20200915104643.2543892-5-ascull@google.com

arch/arm64/include/asm/kvm_asm.h

@@ -60,10 +60,24 @@
 	DECLARE_KVM_VHE_SYM(sym);		\
 	DECLARE_KVM_NVHE_SYM(sym)
 
+#if defined(__KVM_NVHE_HYPERVISOR__)
+
+#define CHOOSE_HYP_SYM(sym)	CHOOSE_NVHE_SYM(sym)
+#define CHOOSE_NVHE_SYM(sym)	sym
+/* The nVHE hypervisor shouldn't even try to access VHE symbols */
+extern void *__nvhe_undefined_symbol;
+#define CHOOSE_VHE_SYM(sym)	__nvhe_undefined_symbol
+
+#elif defined(__KVM_VHE_HYPERVISOR)
+
+#define CHOOSE_HYP_SYM(sym)	CHOOSE_VHE_SYM(sym)
 #define CHOOSE_VHE_SYM(sym)	sym
-#define CHOOSE_NVHE_SYM(sym)	kvm_nvhe_sym(sym)
+/* The VHE hypervisor shouldn't even try to access nVHE symbols */
+extern void *__vhe_undefined_symbol;
+#define CHOOSE_NVHE_SYM(sym)	__vhe_undefined_symbol
+
+#else
 
-#ifndef __KVM_NVHE_HYPERVISOR__
 /*
  * BIG FAT WARNINGS:
  *
@@ -77,10 +91,9 @@
  */
 #define CHOOSE_HYP_SYM(sym)	(is_kernel_in_hyp_mode() ? CHOOSE_VHE_SYM(sym) \
 					   : CHOOSE_NVHE_SYM(sym))
-#else
-/* The nVHE hypervisor shouldn't even try to access anything */
-extern void *__nvhe_undefined_symbol;
-#define CHOOSE_HYP_SYM(sym)	__nvhe_undefined_symbol
+#define CHOOSE_VHE_SYM(sym)	sym
+#define CHOOSE_NVHE_SYM(sym)	kvm_nvhe_sym(sym)
+
 #endif
 
 /* Translate a kernel address @ptr into its equivalent linear mapping */