Markus Armbruster <arm...@redhat.com> writes:
> Option -no-fd-bootchk asks the BIOS to attempt booting from a floppy
> even when the boot sector signature isn't there, by setting a bit in
> RTC CMOS. It was added back in 2006 (commit 52ca8d6a).
>
> Two years later, commit 0ecdffbb added monitor command boot_set.
> Implemented by new function pc_boot_set(). It unconditionally clears
> the floppy signature bit in CMOS.
>
> Commit e0f084bf added -boot option once to automatically change the
> boot order on first reset. Reuses pc_boot_set(), thus also clears the
> floppy signature bit. Commit d9346e81 took care to preserve this
> behavior.
Quite a history there :-)
Does anyone still use no-fd-bootchk? Do you know what the original
use-case was?
> Thus, -no-fd-bootchk applies to any number of boots. Except it
> applies just to the first boot with -boot once, and never after
> boot_set. Weird. Make it stick instead: set the bit according to
> -no-fd-bootchk in pc_boot_set().
>
> Signed-off-by: Markus Armbruster <arm...@redhat.com>
Reviewed-by: Anthony Liguori <aligu...@us.ibm.com>
Regards,
Anthony Liguori
> ---
> hw/i386/pc.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 4844a6b..7e524fc 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -266,7 +266,7 @@ static int boot_device2nibble(char boot_device)
> return 0;
> }
>
> -static int set_boot_dev(ISADevice *s, const char *boot_device, int
> fd_bootchk)
> +static int set_boot_dev(ISADevice *s, const char *boot_device)
> {
> #define PC_MAX_BOOT_DEVICES 3
> int nbds, bds[3] = { 0, };
> @@ -292,7 +292,7 @@ static int set_boot_dev(ISADevice *s, const char
> *boot_device, int fd_bootchk)
>
> static int pc_boot_set(void *opaque, const char *boot_device)
> {
> - return set_boot_dev(opaque, boot_device, 0);
> + return set_boot_dev(opaque, boot_device);
> }
>
> typedef struct pc_cmos_init_late_arg {
> @@ -407,8 +407,7 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t
> above_4g_mem_size,
> cpu_hotplug_cb.cpu_added_notifier.notify = rtc_notify_cpu_added;
> qemu_register_cpu_added_notifier(&cpu_hotplug_cb.cpu_added_notifier);
>
> - /* set boot devices, and disable floppy signature check if requested */
> - if (set_boot_dev(s, boot_device, fd_bootchk)) {
> + if (set_boot_dev(s, boot_device)) {
> exit(1);
> }
>
> --
> 1.7.11.7
