multiboot: set up multiboot information structure

loader.c

@@ -153,6 +153,10 @@ loader_main(struct loader_callbacks *cb, void *arg, int version, int ndisks)
         if (mb->header.mb.header->flags & MULTIBOOT_FLAG_GRAPHICS) {
             ERROR(ENOTSUP, "VBE info requested by kernel, but not supported.");
         }
+
+        if (multiboot_info_finalize(mb)) {
+            ERROR(ECANCELED, "Could not set up multiboot information structure");
+        }
     }
 
     /* Cleanup. */

multiboot.c

@@ -132,6 +132,29 @@ multiboot_info_set_cmdline(struct multiboot_info* info, const char* cmdline)
     return error;
 }
 
+uint32_t
+multiboot_info_finalize(struct multiboot *mb)
+{
+    uint32_t error = 0;
+
+    void* p_addr = allocate(sizeof(struct multiboot_info));
+    if (!p_addr)
+        return ENOMEM;
+
+    error = CALLBACK(copyin, &mb->info, p_addr, sizeof(struct multiboot_info));
+    if (error)
+        return error;
+
+    /*
+     * Multiboot specification, section 3.2:
+     * EBX Must contain the 32-bit physical address of the Multiboot information
+     * structure provided by the boot loader (see spec, section 3.3).
+     */
+    error = CALLBACK(vm_set_register, 0, VM_REG_GUEST_RBX, p_addr);
+
+    return error;
+}
+
 struct multiboot*
 mb_scan(void *kernel, size_t kernsz)
 {

multiboot.h

@@ -278,4 +278,13 @@ multiboot_info_set_loader_name(struct multiboot_info* info, const char* name);
  */
 uint32_t
 multiboot_info_set_cmdline(struct multiboot_info* info, const char* cmdline);
+
+/**
+ * @brief Copy the multiboot structure into the hypervisor and set up registers
+ *
+ * @param mb pointer to the multiboot context
+ * @return uint32_t 0 on success, error code on failure
+ */
+uint32_t multiboot_info_finalize(struct multiboot *mb);
+
 /* vim: set noexpandtab ts=4 : */