WIP: jump into the kernel

loader.c

@@ -197,6 +197,10 @@ loader_main(struct loader_callbacks *cb, void *arg, int version, int ndisks)
         if (multiboot_info_finalize(mb)) {
             ERROR(ECANCELED, "Could not set up multiboot information structure");
         }
+
+        if (multiboot_enter(mb)) {
+            ERROR(ECANCELED, "Could not set up machine state");
+        }
     }
 
     /* Cleanup. */

loader.h

@@ -32,7 +32,7 @@
 
 #include <userboot.h>
 
-#define USERBOOT_VERSION 4
+#define USERBOOT_VERSION 5
 #define MALLOCSZ	(64*1024*1024)
 
 #define BOOTLOADER_NAME "bhyve-multiboot.so"

multiboot.c

@@ -143,12 +143,7 @@ multiboot_info_finalize(struct multiboot *mb)
     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);
+    mb->info_addr = p_addr;
 
     return error;
 }
@@ -605,4 +600,55 @@ multiboot_load(void* kernel, size_t kernsz, struct multiboot *mb)
     }
 }
 
+#define SET_REG(reg, value) do {\
+            error = CALLBACK(vm_set_register, 0, VM_REG_GUEST_ ## reg, value); \
+            if (error) \
+                return error; \
+    } while (0);
+
+#define SET_DESC(reg, base, limit, access) do { \
+            error = CALLBACK(vm_set_desc, 0, VM_REG_GUEST_ ## reg, base, limit, access); \
+            if (error) \
+                return error; \
+    } while (0);
+
+uint32_t
+multiboot_enter(struct multiboot* mb)
+{
+    uint32_t error = 0;
+
+    CALLBACK(vm_set_unrestricted_guest, 0, 1);
+    CALLBACK(vcpu_reset, 0);
+
+#define CR0_NE 0x20
+#define CR0_PE 0x01
+
+    SET_REG(CR0, CR0_NE | CR0_PE);
+
+    SET_DESC(CS, 0, 0xffffffff, 0xc09b);
+    SET_DESC(DS, 0, 0xffffffff, 0xc093);
+    SET_DESC(ES, 0, 0xffffffff, 0xc093);
+    SET_DESC(FS, 0, 0xffffffff, 0xc093);
+    SET_DESC(GS, 0, 0xffffffff, 0xc093);
+    SET_DESC(SS, 0, 0xffffffff, 0xc093);
+
+    SET_REG(CS, 0x10);
+    SET_REG(DS, 0x18);
+    SET_REG(ES, 0x18);
+    SET_REG(FS, 0x18);
+    SET_REG(GS, 0x18);
+    SET_REG(SS, 0x18);
+
+    /*
+     * 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).
+     */
+    SET_REG(RAX, MULTIBOOT1_BOOTLOADER_MAGIC);
+    SET_REG(RBX, mb->info_addr);
+    SET_REG(RIP, mb->entry);
+
+    return error;
+}
+
 /* vim: set noexpandtab ts=4 : */ 

multiboot.h

@@ -185,6 +185,7 @@ struct multiboot {
     void* entry;
     Elf *kernel_elf;
     struct multiboot_info info;
+    void* info_addr;
 };
 
 /**
@@ -302,4 +303,13 @@ uint32_t multiboot_info_finalize(struct multiboot *mb);
  * @return uint32_t 0 on success, error code on failure
  */
 uint32_t multiboot_load_modules(struct multiboot* mb, modules_list_t *modules);
+
+/**
+ * @brief set up machine state to pass execution to the guest kernel
+ *
+ * @param mb pointer to the multiboot context
+ * @return uint32_t 0 on success, error code on failure
+ */
+uint32_t multiboot_enter(struct multiboot* mb);
+
 /* vim: set noexpandtab ts=4 : */ 

tests/test-multiboot.c

@@ -561,11 +561,7 @@ ATF_TC_BODY(info_finalize, tc)
     error = multiboot_info_finalize(&mb);
     ATF_CHECK_EQ_MSG(0, error, "multiboot_info_finalize failed");
 
-    error = vm_get_register(&ctx, 0, VM_REG_GUEST_RBX, &rbx);
-    ATF_CHECK_EQ_MSG(0, error, "vm_get_register failed");
-    ATF_CHECK_MSG(rbx, "RBX should point to the multiboo header");
-
-    callbacks->copyout(callbacks_arg, (uint32_t) rbx & 0xFFFFFFFF, test_buffer,
+    callbacks->copyout(callbacks_arg, (uint32_t) mb.info_addr, test_buffer,
         sizeof(struct multiboot_info));
 
     ATF_CHECK_EQ(0, memcmp(&mb.info, test_buffer,

userboot.h

@@ -259,4 +259,18 @@ struct loader_callbacks {
     int    (*vm_set_register)(void *arg, int vcpu, int reg, uint64_t val);
     int    (*vm_set_desc)(void *arg, int vcpu, int reg, uint64_t base,
                           u_int limit, u_int access);
+
+    /*
+     * Version 5 additions.
+     *
+     * vm_get_unrestricted_guest checks support for the UNRESTRICTED_GUEST
+     * capability and if supported, sets 'retval'. If unsupported, an error
+     * code is returned.
+     *
+     * vm_set_unrestricted_guest sets the UNRESTRICTED_GUEST capability if
+     * supported, and returns an error code otherwise.
+     */
+    int (*vm_get_unrestricted_guest)(void* arg, int vcpu, int *retval);
+    int (*vm_set_unrestricted_guest)(void* arg, int vcpu, int val);
+    int (*vcpu_reset)(void* arg, int vcpu);
 };