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

[Amos Kong <akong@redhat.com>]

Current seabios will try to boot from selected devices first,
if they are all failed, seabios will also try to boot from
un-selected devices.

We need to make it configurable. I already posted a seabios
patch to add 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 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.

Signed-off-by: Amos Kong <akong@redhat.com>
---
[SeaBIOS PATCH v3] boot: add a new type to halt booting
https://github.com/kongove/seabios/commit/39aeded2da6254eab2c34de92371ce1cad5c793e
bios.bin: http://kongove.fedorapeople.org/pub/added-halt-type-bios.bin
---
 qemu-config.c   |    3 +++
 qemu-options.hx |    8 ++++++--
 vl.c            |   28 +++++++++++++++++++++++++++-
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/qemu-config.c b/qemu-config.c
index 2188c3e..dd6d249 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -612,6 +612,9 @@ QemuOptsList qemu_boot_opts = {
         }, {
             .name = "reboot-timeout",
             .type = QEMU_OPT_STRING,
+        }, {
+            .name = "strict",
+            .type = QEMU_OPT_STRING,
         },
         { /*End of list */ }
     },
diff --git a/qemu-options.hx b/qemu-options.hx
index 9df0cde..5408837 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -376,14 +376,14 @@ 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
@@ -407,6 +407,10 @@ 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 79e5122..de79f6c 100644
--- a/vl.c
+++ b/vl.c
@@ -230,6 +230,7 @@ int ctrl_grab = 0;
 unsigned int nb_prom_envs = 0;
 const char *prom_envs[MAX_PROM_ENVS];
 int boot_menu;
+int boot_strict;
 uint8_t *boot_splash_filedata;
 int boot_splash_filedata_size;
 uint8_t qemu_extra_params_fw[2];
@@ -2804,7 +2805,7 @@ 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;
@@ -2847,6 +2848,19 @@ 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 = 1;
+                            } else if (!strcmp(buf, "off")) {
+                                boot_strict = 0;
+                            } else {
+                                fprintf(stderr,
+                                        "qemu: invalid option value '%s'\n",
+                                        buf);
+                                exit(1);
+                            }
+                        }
                         qemu_opts_parse(qemu_find_opts("boot-opts"),
                                         optarg, 0);
                     }
@@ -3907,6 +3921,18 @@ int main(int argc, char **argv, char **envp)
 
     net_check_clients();
 
+    if (boot_strict) {
+        /* do strict boot, only boot from selected devices */
+        FWBootEntry *node;
+
+        QTAILQ_FOREACH(node, &fw_boot_order, link) {
+            if (!node->link.tqe_next) {
+                add_boot_device_path(node->bootindex + 1, NULL, "HALT");
+                break;
+            }
+        }
+    }
+
     /* just use the first displaystate for the moment */
     ds = get_displaystate();
 
-- 
1.7.1