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[Qemu-devel] Re: [PATCH v2] [0.12] Map BIOS f-segment as RAM, not as ROM
From: |
Gleb Natapov |
Subject: |
[Qemu-devel] Re: [PATCH v2] [0.12] Map BIOS f-segment as RAM, not as ROM |
Date: |
Fri, 4 Dec 2009 16:10:04 +0200 |
On Fri, Dec 04, 2009 at 11:33:13AM +0100, Alexander Graf wrote:
> SeaBIOS needs to write to the f-segment. So it needs to have some way to set
> that from read-only to read-write, write in it and when it's done set it to
> read-only again.
>
> On PCI we have a mechanism for that. The ISA machine does not though. To stay
> regression free and happily enable users to continue using the -M isapc
> machine
> let's just map it as RAM. The BIOS on PCI will set it to r/o later either way.
>
> Signed-off-by: Alexander Graf <address@hidden>
>
Looks fine to me. Guest will be able to overwrite BIOS, but I don't
think we should care about this too much. On KVM all ROM slots are
writable anyway.
> ---
>
> v1 -> v2:
>
> - always map r/w
> ---
> hw/pc.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/hw/pc.c b/hw/pc.c
> index 8c1b7ea..b5dabdd 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -1075,7 +1075,7 @@ static void pc_init1(ram_addr_t ram_size,
> isa_bios_size = 128 * 1024;
> cpu_register_physical_memory(0x100000 - isa_bios_size,
> isa_bios_size,
> - (bios_offset + bios_size - isa_bios_size) |
> IO_MEM_ROM);
> + (bios_offset + bios_size - isa_bios_size));
>
>
>
> --
> 1.6.0.2
--
Gleb.