Re: [Qemu-devel] [PATCH 1/2] pc: make vgabios exit port more useful

[Anthony Liguori]

On 08/08/2011 02:31 PM, Anthony Liguori wrote:
> We've always listened on port 501 for vgabios panic messages.  In the entire
> time I've worked on QEMU, I've never actually seen a vgabios panic message :-)
>
> If we change the semantics of this port a little bit, it makes it possible to
> use it for more interesting use-cases.  I chose this approach instead of adding
> a new I/O port because it avoids having a guest visible change.
>
> This change allows single-byte access to port 501 and also uses the value
> written to construct an exit code.
>
> Signed-off-by: Anthony Liguori<address@hidden>

Applied.

Regards,

Anthony Liguori

> ---
>   hw/pc.c |    4 ++--
>   1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/pc.c b/hw/pc.c
> index 1c9d89a..4b07b35 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -549,8 +549,7 @@ static void bochs_bios_write(void *opaque, uint32_t addr, 
> uint32_t val)
>           /* LGPL'ed VGA BIOS messages */
>       case 0x501:
>       case 0x502:
> -        fprintf(stderr, "VGA BIOS panic, line %d\n", val);
> -        exit(1);
> +        exit((val<<  1) | 1);
>       case 0x500:
>       case 0x503:
>   #ifdef DEBUG_BIOS
> @@ -591,6 +590,7 @@ static void *bochs_bios_init(void)
>       register_ioport_write(0x403, 1, 1, bochs_bios_write, NULL);
>       register_ioport_write(0x8900, 1, 1, bochs_bios_write, NULL);
>
> +    register_ioport_write(0x501, 1, 1, bochs_bios_write, NULL);
>       register_ioport_write(0x501, 1, 2, bochs_bios_write, NULL);
>       register_ioport_write(0x502, 1, 2, bochs_bios_write, NULL);
>       register_ioport_write(0x500, 1, 1, bochs_bios_write, NULL);