linux-kernel - Re: [PATCH] x86: mtrr range check correction

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Date:	Tue, 20 Feb 2007 07:47:20 +0000
From:	"Jan Beulich" <jbeulich@...ell.com>
To:	"Chuck Ebbert" <cebbert@...hat.com>
Cc:	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: mtrr range check correction

>>> Chuck Ebbert <cebbert@...hat.com> 18.02.07 22:33 >>>
>Jan Beulich wrote:
>> Whether a region is below 1Mb is determined by its start rather than
>> its end.
>> 
>> This hunk got erroneously dropped from a previous patch.
>> 
>> Signed-off-by: Jan Beulich <jbeulich@...ell.com>
>> 
>> --- linux-2.6.20/arch/i386/kernel/cpu/mtrr/generic.c	2007-02-04 19:44:54.000000000 +0100
>> +++ 2.6.20-x86-mtrr-range-check/arch/i386/kernel/cpu/mtrr/generic.c	2007-02-09 10:17:26.000000000 +0100
>> @@ -428,7 +428,7 @@ int generic_validate_add_page(unsigned l
>>  		}
>>  	}
>>  
>> -	if (base + size < 0x100) {
>> +	if (base < 0x100) {
>>  		printk(KERN_WARNING "mtrr: cannot set region below 1 MiB (0x%lx000,0x%lx000)\n",
>>  		       base, size);
>>  		return -EINVAL;
>> 
>
>What about wraparound?

Should be caught by the subsequent checking of upper bits of first and last byte
being identical.

Jan

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