HV: init and sanitize acrn multiboot info

Initialize and sanitize a acrn specific multiboot info struct with current
supported multiboot1 in very early boot stage, which would bring below
benifits:

- don't need to do hpa2hva convention every time when refering boot_regs;

- panic early if failed to sanitize multiboot info, so that don't need to
  check multiboot info pointer/flags and panic in later boot process;

- keep most code unchanged when introduce multiboot2 support in future;

Tracked-On: #4419

Signed-off-by: Victor Sun <victor.sun@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/boot/include/boot.h

@@ -8,10 +8,37 @@
 #define BOOT_H_
 
 #include <multiboot.h>
+#include <e820.h>
 
 #define MAX_BOOTARGS_SIZE		2048U
+#define MAX_MODULE_COUNT		4U
+
+struct acrn_multiboot_info {
+	uint32_t		mi_flags;	/* the flags is back-compatible with multiboot1 */
+
+	char			*mi_cmdline;
+	char			*mi_loader_name;
+
+	uint32_t		mi_mods_count;
+	struct multiboot_module	mi_mods[MAX_MODULE_COUNT];
+
+	uint32_t 		mi_drives_length;
+	uint32_t		mi_drives_addr;
+
+	uint32_t		mi_mmap_entries;
+	struct multiboot_mmap	mi_mmap_entry[E820_MAX_ENTRIES];
+};
 
 /* boot_regs store the multiboot info magic and address */
 extern uint32_t boot_regs[2];
 
+static inline bool boot_from_multiboot1(void)
+{
+	return ((boot_regs[0] == MULTIBOOT_INFO_MAGIC) && (boot_regs[1] != 0U));
+}
+
+struct acrn_multiboot_info *get_multiboot_info(void);
+int32_t sanitize_multiboot_info(void);
+void parse_hv_cmdline(void);
+
 #endif /* BOOT_H_ */