Re: [Qemu-devel] [PATCHv2] fix linuxboot.bin and multiboot.bin to not hijack int19

[Aurelien Jarno]

On Mon, Jan 31, 2011 at 03:11:01PM +0200, Gleb Natapov wrote:
> Currently linuxboot.bin and multiboot.bin option roms override int19
> vector to intercept boot process. No sane option rom should do that.
> Provide bev entry instead that will be called by BIOS if option rom
> is selected for booting.
> 
> Signed-off-by: Gleb Natapov <address@hidden>
> ---
> 
> Note that this patch should be applied after qemu will upgrade to Seabios
> that supports boot order. Otherwise there will be change in behavior
> since option rom will not be selected for booting by default.
> 
> v1->v2:
>  - change PRODUCT to BOOT_ROM_PRODUCT
>  - move pnp header from OPTION_ROM_START to BOOT_ROM_START

Thanks, applied.

> diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S
> index c109363..748c831 100644
> --- a/pc-bios/optionrom/linuxboot.S
> +++ b/pc-bios/optionrom/linuxboot.S
> @@ -22,6 +22,8 @@
>  
>  #include "optionrom.h"
>  
> +#define BOOT_ROM_PRODUCT "Linux loader"
> +
>  BOOT_ROM_START
>  
>  run_linuxboot:
> diff --git a/pc-bios/optionrom/multiboot.S b/pc-bios/optionrom/multiboot.S
> index 9131837..cc5ca1b 100644
> --- a/pc-bios/optionrom/multiboot.S
> +++ b/pc-bios/optionrom/multiboot.S
> @@ -20,6 +20,8 @@
>  
>  #include "optionrom.h"
>  
> +#define BOOT_ROM_PRODUCT "multiboot loader"
> +
>  #define MULTIBOOT_MAGIC              0x2badb002
>  
>  #define GS_PROT_JUMP         0
> diff --git a/pc-bios/optionrom/optionrom.h b/pc-bios/optionrom/optionrom.h
> index fbdd48a..aa783de 100644
> --- a/pc-bios/optionrom/optionrom.h
> +++ b/pc-bios/optionrom/optionrom.h
> @@ -97,22 +97,28 @@
>  
>  #define BOOT_ROM_START                                       \
>       OPTION_ROM_START                                \
> -     push            %eax;                           \
> -     push            %ds;                            \
> -                                                     \
> -     /* setup ds so we can access the IVT */         \
> -     xor             %ax, %ax;                       \
> -     mov             %ax, %ds;                       \
> -                                                     \
> -     /* install our int 19 handler */                \
> -     movw            $int19_handler, (0x19*4);       \
> -     mov             %cs, (0x19*4+2);                \
> -                                                     \
> -     pop             %ds;                            \
> -     pop             %eax;                           \
>       lret;                                           \
> -                                                     \
> -    int19_handler:;                                  \
> +     .org            0x18;                           \
> +     .short          0;                              \
> +     .short          _pnph;                          \
> +    _pnph:                                           \
> +     .ascii          "$PnP";                         \
> +     .byte           0x01;                           \
> +     .byte           ( _pnph_len / 16 );             \
> +     .short          0x0000;                         \
> +     .byte           0x00;                           \
> +     .byte           0x00;                           \
> +     .long           0x00000000;                     \
> +     .short          _manufacturer;                  \
> +     .short          _product;                       \
> +     .long           0x00000000;                     \
> +     .short          0x0000;                         \
> +     .short          0x0000;                         \
> +     .short          _bev;                           \
> +     .short          0x0000;                         \
> +     .short          0x0000;                         \
> +     .equ            _pnph_len, . - _pnph;           \
> +    _bev:;                                           \
>       /* DS = CS */                                   \
>       movw            %cs, %ax;                       \
>       movw            %ax, %ds;
> @@ -122,5 +128,9 @@
>      _end:
>  
>  #define BOOT_ROM_END                                 \
> +    _manufacturer:;                                  \
> +     .asciz "QEMU";                                  \
> +    _product:;                                               \
> +     .asciz BOOT_ROM_PRODUCT;                        \
>       OPTION_ROM_END
>  
> --
>                       Gleb.
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net