diff --git a/arch/x86/include/asm/acrn.h b/arch/x86/include/asm/acrn.h
index 127f20672c5d36e5e411c1cf700c690aa15ec527..e003a01b7c6721f6dfcddd148e4be6847b3d67ce 100644
--- a/arch/x86/include/asm/acrn.h
+++ b/arch/x86/include/asm/acrn.h
@@ -21,4 +21,58 @@ static inline u32 acrn_cpuid_base(void)
 	return 0;
 }
 
+/*
+ * Hypercalls for ACRN
+ *
+ * - VMCALL instruction is used to implement ACRN hypercalls.
+ * - ACRN hypercall ABI:
+ *   - Hypercall number is passed in R8 register.
+ *   - Up to 2 arguments are passed in RDI, RSI.
+ *   - Return value will be placed in RAX.
+ *
+ * Because GCC doesn't support R8 register as direct register constraints, use
+ * supported constraint as input with a explicit MOV to R8 in beginning of asm.
+ */
+static inline long acrn_hypercall0(unsigned long hcall_id)
+{
+	long result;
+
+	asm volatile("movl %1, %%r8d\n\t"
+		     "vmcall\n\t"
+		     : "=a" (result)
+		     : "g" (hcall_id)
+		     : "r8", "memory");
+
+	return result;
+}
+
+static inline long acrn_hypercall1(unsigned long hcall_id,
+				   unsigned long param1)
+{
+	long result;
+
+	asm volatile("movl %1, %%r8d\n\t"
+		     "vmcall\n\t"
+		     : "=a" (result)
+		     : "g" (hcall_id), "D" (param1)
+		     : "r8", "memory");
+
+	return result;
+}
+
+static inline long acrn_hypercall2(unsigned long hcall_id,
+				   unsigned long param1,
+				   unsigned long param2)
+{
+	long result;
+
+	asm volatile("movl %1, %%r8d\n\t"
+		     "vmcall\n\t"
+		     : "=a" (result)
+		     : "g" (hcall_id), "D" (param1), "S" (param2)
+		     : "r8", "memory");
+
+	return result;
+}
+
 #endif /* _ASM_X86_ACRN_H */