hv: riscv: Add ACRN specific SBI extension skeleton

This is used to implement hypercall in the future.

Tracked-On: #8841
Signed-off-by: Yifan Liu <yifan1.liu@intel.com>
Acked-by: Wang Yu1 <yu1.wang@intel.com>

hypervisor/include/arch/riscv/asm/guest/vsbi.h

@@ -13,6 +13,13 @@
 
 #define MAX_VSBI_EXTENSION_NAME 16
 
+/* TODO: This ID is distributed by SBI.
+ * For now just hardcode a random value that isn't used.
+ * Change to official ID when ACRN gets an ID.
+ */
+#define SBI_ACRN_IMPL_ID	0x900
+#define SBI_EID_ACRN	(SBI_EID_FIRMWARE_START + SBI_ACRN_IMPL_ID)
+
 struct vsbi_ret {
 	uint64_t value;
 	bool vcpu_retain_pc;

hypervisor/include/arch/riscv/asm/sbi.h

@@ -29,6 +29,9 @@ enum sbi_eid  {
 	/* Vendor extensions must lie within this range */
 	SBI_EID_VENDOR_START = 0x09000000,
 	SBI_EID_VENDOR_END = 0x09FFFFFF,
+
+	SBI_EID_FIRMWARE_START = 0x0A000000,
+	SBI_EID_FIRMWARE_END = 0x0AFFFFFF,
 };
 
 #define SBI_BASE_FID_GET_SPEC_VERSION		0x0