diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index d5b313978888..92930cef4bff 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -340,6 +340,8 @@ struct kvm_arch {
 #define KVM_ARCH_FLAG_ID_REGS_INITIALIZED		7
 	/* Fine-Grained UNDEF initialised */
 #define KVM_ARCH_FLAG_FGU_INITIALIZED			8
+	/* Guest has bought into the MMIO guard extension */
+#define KVM_ARCH_FLAG_MMIO_GUARD			9
 	unsigned long flags;
 
 	/* VM-wide vCPU feature set */