Build arch/x86/kvm as an external module: the include path and the shared
virt/kvm makefile must come from the module tree, not from the headers.
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -1,9 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0
 
-ccflags-y += -I $(srctree)/arch/x86/kvm
+ccflags-y += -I $(src)
 ccflags-$(CONFIG_KVM_WERROR) += -Werror
 
-include $(srctree)/virt/kvm/Makefile.kvm
+include $(src)/../../../virt/kvm/Makefile.kvm
 
 kvm-y			+= x86.o emulate.o irq.o lapic.o cpuid.o pmu.o mtrr.o \
 			   debugfs.o mmu/mmu.o mmu/page_track.o mmu/spte.o
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -1968,7 +1968,7 @@
 #endif /* _TRACE_KVM_H */
 
 #undef TRACE_INCLUDE_PATH
-#define TRACE_INCLUDE_PATH ../../arch/x86/kvm
+#define TRACE_INCLUDE_PATH .
 #undef TRACE_INCLUDE_FILE
 #define TRACE_INCLUDE_FILE trace