From 8281abd548d840d84223e66812491918c713e56c Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Fri, 14 Jun 2013 13:15:03 +0200 Subject: [PATCH] vl: Fix -boot order and once regressions, and related bugs Option "once" sets up a different boot order just for the initial boot. Boot order reverts back to normal on reset. Option "order" changes the normal boot order. The reversal is implemented by reset handler restore_boot_devices(), which takes the boot order to revert to as argument. restore_boot_devices() does nothing on its first call, because that must be the initial machine reset. On its second call, it changes the boot order back, and unregisters itself. Because we register the handler right when -boot gets parsed, we can revert to an incorrect normal boot order, and multiple -boot can interact in funny ways. Here's how things work without -boot once or order: * boot_devices is "". * main() passes machine->boot_order to to machine->init(), because boot_devices is "". machine->init() configures firmware accordingly. For PC machines, machine->boot_order is "cad", and pc_cmos_init() writes it to RTC CMOS, where SeaBIOS picks it up. Now consider -boot order=: * boot_devices is "". * -boot order= sets boot_devices to "" (no change). * main() passes machine->boot_order to to machine->init(), because boot_devices is "", as above. Bug: -boot order= has no effect. Broken in commit e4ada29e. Next, consider -boot once=a: * boot_devices is "". * -boot once=a registers restore_boot_devices() with argument "", and sets boot_devices to "a". * main() passes boot_devices "a" to machine->init(), which configures firmware accordingly. For PC machines, pc_cmos_init() writes the boot order to RTC CMOS. * main() calls qemu_system_reset(). This runs reset handlers. - restore_boot_devices() gets called with argument "". Does nothing, because it's the first call. * Machine boots, boot order is "a". * Machine resets (e.g. monitor command). Reset handlers run. - restore_boot_devices() gets called with argument "". Calls qemu_boot_set("") to reconfigure firmware. For PC machines, pc_boot_set() writes it into RTC CMOS. Reset handler unregistered. Bug: boot order reverts to "" instead of machine->boot_order. The actual boot order depends on how firmware interprets "". Broken in commit e4ada29e. Next, consider -boot once=a -boot order=c: * boot_devices is "". * -boot once=a registers restore_boot_devices() with argument "", and sets boot_devices to "a". * -boot order=c sets boot_devices to "c". * main() passes boot_devices "c" to machine->init(), which configures firmware accordingly. For PC machines, pc_cmos_init() writes the boot order to RTC CMOS. * main() calls qemu_system_reset(). This runs reset handlers. - restore_boot_devices() gets called with argument "". Does nothing, because it's the first call. * Machine boots, boot order is "c". Bug: it should be "a". I figure this has always been broken. * Machine resets (e.g. monitor command). Reset handlers run. - restore_boot_devices() gets called with argument "". Calls qemu_boot_set("") to reconfigure firmware. For PC machines, pc_boot_set() writes it into RTC CMOS. Reset handler unregistered. Bug: boot order reverts to "" instead of "c". I figure this has always been broken, just differently broken before commit e4ada29e. Next, consider -boot once=a -boot once=b -boot once=c: * boot_devices is "". * -boot once=a registers restore_boot_devices() with argument "", and sets boot_devices to "a". * -boot once=b registers restore_boot_devices() with argument "a", and sets boot_devices to "b". * -boot once=c registers restore_boot_devices() with argument "b", and sets boot_devices to "c". * main() passes boot_devices "c" to machine->init(), which configures firmware accordingly. For PC machines, pc_cmos_init() writes the boot order to RTC CMOS. * main() calls qemu_system_reset(). This runs reset handlers. - restore_boot_devices() gets called with argument "". Does nothing, because it's the first call. - restore_boot_devices() gets called with argument "a". Calls qemu_boot_set("a") to reconfigure firmware. For PC machines, pc_boot_set() writes it into RTC CMOS. Reset handler unregistered. - restore_boot_devices() gets called with argument "b". Calls qemu_boot_set("b") to reconfigure firmware. For PC machines, pc_boot_set() writes it into RTC CMOS. Reset handler unregistered. * Machine boots, boot order is "b". Bug: should really be "c", because that came last, and for all other -boot options, the last one wins. I figure this was broken some time before commit 37905d6a, and fixed there only for a single occurence of "once". * Machine resets (e.g. monitor command). Reset handlers run. - restore_boot_devices() gets called with argument "". Calls qemu_boot_set("") to reconfigure firmware. For PC machines, pc_boot_set() writes it into RTC CMOS. Reset handler unregistered. Same bug as above: boot order reverts to "" instead of machine->boot_order. Fix by acting upon -boot options order, once and menu only after option parsing is complete, and the machine is known. This is how the other -boot options work already. Signed-off-by: Markus Armbruster Reviewed-by: Anthony Liguori Message-id: 1371208516-7857-4-git-send-email-armbru@redhat.com Signed-off-by: Anthony Liguori --- vl.c | 59 ++++++++++++++++++++++++++++++----------------------------- 1 file changed, 30 insertions(+), 29 deletions(-) diff --git a/vl.c b/vl.c index ed92463daf..ea4e1ef080 100644 --- a/vl.c +++ b/vl.c @@ -2841,7 +2841,7 @@ int main(int argc, char **argv, char **envp) const char *icount_option = NULL; const char *initrd_filename; const char *kernel_filename, *kernel_cmdline; - char boot_devices[33] = ""; + const char *boot_order = NULL; DisplayState *ds; int cyls, heads, secs, translation; QemuOpts *hda_opts = NULL, *opts, *machine_opts; @@ -3131,31 +3131,9 @@ int main(int argc, char **argv, char **envp) drive_add(IF_DEFAULT, 2, optarg, CDROM_OPTS); break; case QEMU_OPTION_boot: - { - char *standard_boot_devices; - const char *order, *once; - - opts = qemu_opts_parse(qemu_find_opts("boot-opts"), - optarg, 1); - if (!opts) { - exit(1); - } - - order = qemu_opt_get(opts, "order"); - if (order) { - validate_bootdevices(order); - pstrcpy(boot_devices, sizeof(boot_devices), order); - } - - once = qemu_opt_get(opts, "once"); - if (once) { - validate_bootdevices(once); - standard_boot_devices = g_strdup(boot_devices); - pstrcpy(boot_devices, sizeof(boot_devices), once); - qemu_register_reset(restore_boot_devices, - standard_boot_devices); - } - boot_menu = qemu_opt_get_bool(opts, "menu", boot_menu); + opts = qemu_opts_parse(qemu_find_opts("boot-opts"), optarg, 1); + if (!opts) { + exit(1); } break; case QEMU_OPTION_fda: @@ -4096,6 +4074,31 @@ int main(int argc, char **argv, char **envp) kernel_filename = initrd_filename = kernel_cmdline = NULL; } + if (!boot_order) { + boot_order = machine->boot_order; + } + opts = qemu_opts_find(qemu_find_opts("boot-opts"), NULL); + if (opts) { + char *normal_boot_order; + const char *order, *once; + + order = qemu_opt_get(opts, "order"); + if (order) { + validate_bootdevices(order); + boot_order = order; + } + + once = qemu_opt_get(opts, "once"); + if (once) { + validate_bootdevices(once); + normal_boot_order = g_strdup(boot_order); + boot_order = once; + qemu_register_reset(restore_boot_devices, normal_boot_order); + } + + boot_menu = qemu_opt_get_bool(opts, "menu", boot_menu); + } + if (!kernel_cmdline) { kernel_cmdline = ""; } @@ -4260,9 +4263,7 @@ int main(int argc, char **argv, char **envp) qdev_machine_init(); QEMUMachineInitArgs args = { .ram_size = ram_size, - .boot_device = (boot_devices[0] == '\0') ? - machine->boot_order : - boot_devices, + .boot_device = boot_order, .kernel_filename = kernel_filename, .kernel_cmdline = kernel_cmdline, .initrd_filename = initrd_filename, -- 2.11.4.GIT