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

From: H. Peter Anvin
Date: Wed May 12 2010 - 14:56:45 EST


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.

-hpa
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