bootdevice: check boot order argument validation before vm running

Either 'once' option or 'order' option can take effect for -boot at
the same time, that is say initial startup processing can check only
one. And pc.c's set_boot_dev() fails when its boot order argument
is invalid. This patch provide a solution fix this problem:

 1. If "once" is given, register reset handler to restore boot order.

 2. Pass the normal boot order to machine creation.  Should fail when
   the normal boot order is invalid.

 3. If "once" is given, set it with qemu_boot_set().  Fails when the
   once boot order is invalid.

 4. Start the machine.

 5. On reset, the reset handler calls qemu_boot_set() to restore boot
   order.  Should never fail.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

diff --git a/vl.c b/vl.c
index 86bdce07e30622ed4c7c6c7aca1b0f7bdb4f0c1a..e9d5a363adacb9ffdc895143fedbd2a45175ced1 100644 (file)
--- a/vl.c
+++ b/vl.c
@@ -2729,7 +2729,8 @@ int main(int argc, char **argv, char **envp)
     int snapshot, linux_boot;
     const char *initrd_filename;
     const char *kernel_filename, *kernel_cmdline;
-    const char *boot_order;
+    const char *boot_order = NULL;
+    const char *boot_once = NULL;
     DisplayState *ds;
     int cyls, heads, secs, translation;
     QemuOpts *hda_opts = NULL, *opts, *machine_opts, *icount_opts = NULL;
@@ -4029,39 +4030,36 @@ int main(int argc, char **argv, char **envp)
     kernel_cmdline = qemu_opt_get(machine_opts, "append");
     bios_name = qemu_opt_get(machine_opts, "firmware");
 
-    boot_order = machine_class->default_boot_order;
     opts = qemu_opts_find(qemu_find_opts("boot-opts"), NULL);
     if (opts) {
-        char *normal_boot_order;
-        const char *order, *once;
         Error *local_err = NULL;
 
-        order = qemu_opt_get(opts, "order");
-        if (order) {
-            validate_bootdevices(order, &local_err);
+        boot_order = qemu_opt_get(opts, "order");
+        if (boot_order) {
+            validate_bootdevices(boot_order, &local_err);
             if (local_err) {
                 error_report_err(local_err);
                 exit(1);
             }
-            boot_order = order;
         }
 
-        once = qemu_opt_get(opts, "once");
-        if (once) {
-            validate_bootdevices(once, &local_err);
+        boot_once = qemu_opt_get(opts, "once");
+        if (boot_once) {
+            validate_bootdevices(boot_once, &local_err);
             if (local_err) {
                 error_report_err(local_err);
                 exit(1);
             }
-            normal_boot_order = g_strdup(boot_order);
-            boot_order = once;
-            qemu_register_reset(restore_boot_order, normal_boot_order);
         }
 
         boot_menu = qemu_opt_get_bool(opts, "menu", boot_menu);
         boot_strict = qemu_opt_get_bool(opts, "strict", false);
     }
 
+    if (!boot_order) {
+        boot_order = machine_class->default_boot_order;
+    }
+
     if (!kernel_cmdline) {
         kernel_cmdline = "";
         current_machine->kernel_cmdline = (char *)kernel_cmdline;
@@ -4228,6 +4226,16 @@ int main(int argc, char **argv, char **envp)
 
     net_check_clients();
 
+    if (boot_once) {
+        Error *local_err = NULL;
+        qemu_boot_set(boot_once, &local_err);
+        if (local_err) {
+            error_report("%s", error_get_pretty(local_err));
+            exit(1);
+        }
+        qemu_register_reset(restore_boot_order, g_strdup(boot_order));
+    }
+
     ds = init_displaystate();
 
     /* init local displays */