Re: [Patch 1/1] x86 efi: Fill all reserved memmap entries if add_efi_memmapspecified.

From: Yinghai
Date: Wed May 12 2010 - 16:21:46 EST


On 05/12/2010 11:55 AM, H. Peter Anvin wrote:
> On 05/12/2010 11:10 AM, Mike Travis wrote:
>>
>> Currently, the e820_reserve_resources() function does not add entries
>> obtained via the "add_efi_memmap" kernel cmdline option. This causes
>> /sys/firmware/memmap/... to be incomplete (stops after 128 entries).
>> Utilities that examine these entries then do not get the complete
>> picture of system memory.
>>
>> This patch causes the above function to use the e820 memmap instead
>> of the e820_saved memmap if "add_efi_memmap" cmdline option is
>> specified.
>>
>> Signed-off-by: Mike Travis <travis@xxxxxxx>
>> Signed-off-by: Jack Steiner <steiner@xxxxxxx>
>
> If I'm not mistaken, the very reason for the e820 vs e820_saved map is
> that the latter is supposed to reflect the firmware report, whereas the
> former is subject to be modified by the kernel. As this is actually a
> reflection of the firmware (although it would be better if you could fix
> the bootloader instead of adding hacks in the kernel...) it really
> should go into e820_saved as well as e820. Displaying the adjusted e820
> map doesn't seem appropriate under any circumstances.

Yes, you are right.

We should not touch e820_saved and keep /sys/firmware/memmap to be consistent with it.

YH
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