[Qemu-devel] [PATCH v3] add a boot option to do strict boot

[Amos Kong <akong@redhat.com>]

Seabios already added a new device type to halt booting.
Qemu can add "HALT" at the end of bootindex string, then
seabios will halt booting after trying to boot from all
selected devices.

This patch added a new boot option to configure if boot
from un-selected devices.

This option only effects when boot priority is changed by
bootindex options, the old style(-boot order=..) will still
try to boot from un-selected devices.

v2: add HALT entry in get_boot_devices_list()
v3: rebase to latest qemu upstream

Signed-off-by: Amos Kong <akong@redhat.com>
---
As we discussed in the past, we need to introduce a general
query-config command to tell libvirt the supported options.
Anthony will do it?

http://lists.nongnu.org/archive/html/qemu-devel/2013-03/msg00349.html
---
 qemu-options.hx |    8 ++++++--
 vl.c            |   25 ++++++++++++++++++++++++-
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 30fb85d..06dd565 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -161,14 +161,14 @@ ETEXI
 
 DEF("boot", HAS_ARG, QEMU_OPTION_boot,
     "-boot [order=drives][,once=drives][,menu=on|off]\n"
-    "      [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time]\n"
+    "      [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
     "                'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
     "                'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
     "                'sp_time': the period that splash picture last if menu=on, unit is ms\n"
     "                'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
     QEMU_ARCH_ALL)
 STEXI
-@item -boot [order=@var{drives}][,once=@var{drives}][,menu=on|off][,splash=@var{sp_name}][,splash-time=@var{sp_time}][,reboot-timeout=@var{rb_timeout}]
+@item -boot [order=@var{drives}][,once=@var{drives}][,menu=on|off][,splash=@var{sp_name}][,splash-time=@var{sp_time}][,reboot-timeout=@var{rb_timeout}][,strict=on|off]
 @findex -boot
 Specify boot order @var{drives} as a string of drive letters. Valid
 drive letters depend on the target achitecture. The x86 PC uses: a, b
@@ -192,6 +192,10 @@ when boot failed, then reboot. If @var{rb_timeout} is '-1', guest will not
 reboot, qemu passes '-1' to bios by default. Currently Seabios for X86
 system support it.
 
+Do strict boot via @option{strict=on} as far as firmware/BIOS
+supports it. This only effects when boot priority is changed by
+bootindex options. The default is non-strict boot.
+
 @example
 # try to boot from network first, then from hard disk
 qemu-system-i386 -boot order=nc
diff --git a/vl.c b/vl.c
index ce51e65..aeed7f4 100644
--- a/vl.c
+++ b/vl.c
@@ -234,6 +234,7 @@ int ctrl_grab = 0;
 unsigned int nb_prom_envs = 0;
 const char *prom_envs[MAX_PROM_ENVS];
 int boot_menu;
+bool boot_strict;
 uint8_t *boot_splash_filedata;
 size_t boot_splash_filedata_size;
 uint8_t qemu_extra_params_fw[2];
@@ -458,6 +459,9 @@ static QemuOptsList qemu_boot_opts = {
         }, {
             .name = "reboot-timeout",
             .type = QEMU_OPT_STRING,
+        }, {
+            .name = "strict",
+            .type = QEMU_OPT_STRING,
         },
         { /*End of list */ }
     },
@@ -1267,6 +1271,12 @@ char *get_boot_devices_list(size_t *size)
 
     *size = total;
 
+    if (boot_strict && *size > 0) {
+        list[total-1] = '\n';
+        list = g_realloc(list, total + 4);
+        memcpy(&list[total], "HALT", 4);
+        *size = total + 4;
+    }
     return list;
 }
 
@@ -3131,7 +3141,7 @@ int main(int argc, char **argv, char **envp)
                     static const char * const params[] = {
                         "order", "once", "menu",
                         "splash", "splash-time",
-                        "reboot-timeout", NULL
+                        "reboot-timeout", "strict", NULL
                     };
                     char buf[sizeof(boot_devices)];
                     char *standard_boot_devices;
@@ -3174,6 +3184,19 @@ int main(int argc, char **argv, char **envp)
                                 exit(1);
                             }
                         }
+                        if (get_param_value(buf, sizeof(buf),
+                                            "strict", optarg)) {
+                            if (!strcmp(buf, "on")) {
+                                boot_strict = true;
+                            } else if (!strcmp(buf, "off")) {
+                                boot_strict = false;
+                            } else {
+                                fprintf(stderr,
+                                        "qemu: invalid option value '%s'\n",
+                                        buf);
+                                exit(1);
+                            }
+                        }
                         if (!qemu_opts_parse(qemu_find_opts("boot-opts"),
                                              optarg, 0)) {
                             exit(1);
-- 
1.7.1