Re: [PATCH 2/3] x86: mtrr_cleanup: first 1M should be coverred in var mtrrs

["H. Peter Anvin" <hpa@zytor.com>]

Yinghai Lu wrote:
>> The first 1 MB is a total don't care for the variable MTRRs -- they don't
>> have to be covered *or* uncovered, since the entire first 1 MB is addressed
>> by fixed MTRRs.
> 
> so it is safe to put it in WB, and can be spare some regs because it
> start from base 0.

Yes, my point was that you can make those whatever you want.  It doesn't 
have to be WB; it can be any value.

>> In practice, it is *likely* that you're going to want to merge it with a WB
>> MTRR, but with various vendors doing all kinds of strange things on
>> EFI-damaged platforms, it may not always be that way.
> 
> EFI will not use fixed-mtrr for first 1M? and not cover first 1M in
> var mtrr with WB? that will run out mtrr regs..

There are some systems which, apparently, don't have RAM there.  Don't 
ask me how or why.

	-hpa