Re: [Patch] Expand shadow memory area for using option ROM

[Akio Takebe <takebe_akio@jp.fujitsu.com>]

Keir Fraser wrote
> On 26/12/2008 04:46, "Akio Takebe" <takebe_akio@jp.fujitsu.com> wrote:
> 
>> This patch is:
>> - replace e820 table from 0xe0000 to 0xeb000.
>> - expand shadowr from 0xc0000-0xdffff to 0xc0000-0xe8fff.
>> - fix scan size of VGA BIOS.
>>
>> after this patch, BIOS map is below.
>>  BIOS map:
>>   c0000-c8fff: VGA BIOS
>>   c9000-d57ff: Etherboot ROM
>>   d5800-e0fff: PCI Option ROMs
>>   e9000-e919c: SMBIOS tables
>>   f0000-fffff: Main BIOS
> 
> Comments:
> 
> 1. Why does the VGA BIOS 'scan size' need to be fixed? What's wrong with
> scanning only up to 0xc8000 for it, and letting option ROMs continue to
> reside from 0xc8000? Indeed, won't the VGABIOS always be at 0xc0000, so we
> could actually only probe that address for it, and let option ROMs load as
> low as 0xc0800?

Because the current VGA BIOS uses 0xc0000-0xc8fff from the following log.
I want just to avoid the unnecessary scanning.

(XEN) HVM1: BIOS map:
(XEN) HVM1:  c0000-c8fff: VGA BIOS
(XEN) HVM1:  c9000-d57ff: Etherboot ROM
(XEN) HVM1:  e9000-e919c: SMBIOS tables
(XEN) HVM1:  f0000-fffff: Main BIOS

I think rombios works fine if we drop the part of the patch.

> 
> 2. It'd be nice to give E820_PHYSICAL_ADDRESS a definition in config.h and
> then use that instead of hardcoding the address throughout rombios.c.
> 
I'll try it.

Best Regards,

Akio Takebe