Re: [PATCH] x86: add phys addr validity check for /dev/mem mmap

[Simon Jeons <simon.jeons@gmail.com>]

Hi H.Peter,
On 04/11/2013 10:48 AM, H. Peter Anvin wrote:
> On 04/10/2013 07:40 PM, Simon Jeons wrote:
>> Hi H.Peter,
>> On 04/04/2013 09:13 AM, H. Peter Anvin wrote:
>>> On 04/03/2013 06:11 PM, Simon Jeons wrote:
>>>> Why we consider boot_cpu_data.x86_phys_bits instead of e820 map here?
>>>>
>>> Because x86_phys_bits is what controls how much address space the
>>> processor has.  e820 tells us how much *RAM* the machine has, or
>>> specifically, how much RAM the machine had on boot.
>> I have 8GB memory in my machine, but when I accumulated every e820
>> ranges which dump in dmesg, there are 25MB memory less then 8GB(1024*8)
>> memory, why 25MB miss?
>>
> For whatever reason your BIOS is stealing some memory, possibly for video.

Thanks for your quick response. ;-)
My machine is new which have i7 cpu. How much memory video need? 8MB? 
Why I miss 25MB?

>
> 	-hpa
>
>

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