Re: [Qemu-devel] [PATCH] isapc: Shadow ISA BIOS by default

[Jan Kiszka <jan.kiszka@siemens.com>]

[forgot to CC stable: this one apparently qualifies for older QEMU
releases as well but would require some adaptions for < 1.1]

On 2012-09-11 17:53, Jan Kiszka wrote:
> Our one and only BIOS depends on a writable shadowed BIOS in the ISA
> range. As we have no interface to control the write property, make that
> region writable by default.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
> 
> This unbreaks isapc for TCG, and keep it working for KVM once it starts
> supporting read-only memslots.
> 
>  hw/pc_sysfw.c |   13 +++++++++----
>  1 files changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
> index b45f0ac..027d98a 100644
> --- a/hw/pc_sysfw.c
> +++ b/hw/pc_sysfw.c
> @@ -136,6 +136,7 @@ static void old_pc_system_rom_init(MemoryRegion *rom_memory)
>  {
>      char *filename;
>      MemoryRegion *bios, *isa_bios;
> +    void *isa_bios_ptr;
>      int bios_size, isa_bios_size;
>      int ret;
>  
> @@ -167,19 +168,23 @@ static void old_pc_system_rom_init(MemoryRegion *rom_memory)
>          g_free(filename);
>      }
>  
> -    /* map the last 128KB of the BIOS in ISA space */
> +    /* Shadow the last 128KB of the BIOS in ISA space as RAM -
> +     * Seabios depends on this */
>      isa_bios_size = bios_size;
>      if (isa_bios_size > (128 * 1024)) {
>          isa_bios_size = 128 * 1024;
>      }
>      isa_bios = g_malloc(sizeof(*isa_bios));
> -    memory_region_init_alias(isa_bios, "isa-bios", bios,
> -                             bios_size - isa_bios_size, isa_bios_size);
> +    memory_region_init_ram(isa_bios, "isa-bios", isa_bios_size);
> +    vmstate_register_ram_global(isa_bios);
>      memory_region_add_subregion_overlap(rom_memory,
>                                          0x100000 - isa_bios_size,
>                                          isa_bios,
>                                          1);
> -    memory_region_set_readonly(isa_bios, true);
> +
> +    /* copy ISA rom image from top of the ROM */
> +    isa_bios_ptr = memory_region_get_ram_ptr(isa_bios);
> +    rom_copy(isa_bios_ptr, (uint32_t)(-isa_bios_size), isa_bios_size);
>  
>      /* map all the bios at the top of memory */
>      memory_region_add_subregion(rom_memory,
> 

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