Re: [Qemu-devel] [PATCH 2/2] pc: remove DEBUG_BIOS define and QEMU exit I/O ports

[Anthony Liguori <aliguori@us.ibm.com>]

On 07/06/2012 04:53 PM, Hervé Poussineau wrote:
> Debug output ports (enabled by DEBUG_BIOS define) can be replaced by:
> -chardev stdio,id=debugcon,mux=on
> -device isa-debugcon,iobase=0x402,chardev=debugcon
> -device isa-debugcon,iobase=0x403,chardev=debugcon
> -device isa-debugcon,iobase=0x500,chardev=debugcon
> -device isa-debugcon,iobase=0x503,chardev=debugcon
>
> QEMU exit (which can be guest trigged) can be replaced by:
> -device isa-debugexit,iobase=0x501
> -device isa-debugexit,iobase=0x501,access-size=2
> -device isa-debugexit,iobase=0x502,access-size=2
>
> Signed-off-by: Hervé Poussineau<hpoussin@reactos.org>
> ---
>
> Anthony, this patch is a follow-up of a patch I sent in March 2012:
> http://lists.gnu.org/archive/html/qemu-devel/2012-03/msg00031.html
>
> Will you accept this approach, where your regression suite will require
> a new parameter "-device isa-debugexit,iobase=0x501" ?
>
>   hw/pc.c |   35 -----------------------------------
>   1 file changed, 35 deletions(-)
>
> diff --git a/hw/pc.c b/hw/pc.c
> index c7e9ab3..a328fb2 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -49,9 +49,6 @@
>   #include "exec-memory.h"
>   #include "arch_init.h"
>
> -/* output Bochs bios info messages */
> -//#define DEBUG_BIOS
> -
>   /* debug PC/ISA interrupts */
>   //#define DEBUG_IRQ
>
> @@ -540,17 +537,6 @@ static void bochs_bios_write(void *opaque, uint32_t addr, uint32_t val)
>       static int shutdown_index = 0;
>
>       switch(addr) {
> -        /* Bochs BIOS messages */
> -    case 0x400:
> -    case 0x401:
> -        /* used to be panic, now unused */
> -        break;
> -    case 0x402:
> -    case 0x403:
> -#ifdef DEBUG_BIOS
> -        fprintf(stderr, "%c", val);
> -#endif
> -        break;
>       case 0x8900:
>           /* same as Bochs power off */
>           if (val == shutdown_str[shutdown_index]) {
> @@ -563,17 +549,6 @@ static void bochs_bios_write(void *opaque, uint32_t addr, uint32_t val)
>               shutdown_index = 0;
>           }
>           break;
> -
> -        /* LGPL'ed VGA BIOS messages */
> -    case 0x501:
> -    case 0x502:
> -        exit((val<<  1) | 1);
> -    case 0x500:
> -    case 0x503:
> -#ifdef DEBUG_BIOS
> -        fprintf(stderr, "%c", val);
> -#endif
> -        break;
>       }
>   }
>
> @@ -602,18 +577,8 @@ static void *bochs_bios_init(void)
>       uint64_t *numa_fw_cfg;
>       int i, j;
>
> -    register_ioport_write(0x400, 1, 2, bochs_bios_write, NULL);
> -    register_ioport_write(0x401, 1, 2, bochs_bios_write, NULL);
> -    register_ioport_write(0x402, 1, 1, bochs_bios_write, NULL);
> -    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);
> -    register_ioport_write(0x503, 1, 1, bochs_bios_write, NULL);
> -
>       fw_cfg = fw_cfg_init(BIOS_CFG_IOPORT, BIOS_CFG_IOPORT + 1, 0, 0);
>
>       fw_cfg_add_i32(fw_cfg, FW_CFG_ID, 1);

Removing this from the default PC breaks compatibility.  I don't mind having a 
way to disable it but it needs to be there by default.

Among other things, my test suite depends on these ports.

Regards,

Anthony Liguori