linux-kernel - Re: [PATCH] Fix e820 end address with EFI

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Date:	Mon, 02 Mar 2009 17:28:14 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Huang Ying <ying.huang@...el.com>
CC:	Brian Maly <bmaly@...hat.com>, Ingo Molnar <mingo@...e.hu>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Fix e820 end address with EFI

Huang Ying wrote:
> On Tue, 2009-03-03 at 05:38 +0800, Yinghai Lu wrote:
>> Huang Ying wrote:
>>> On Mon, 2009-03-02 at 10:51 +0800, Yinghai Lu wrote:
>>>> On Sun, Mar 1, 2009 at 6:37 PM, Huang Ying <ying.huang@...el.com> wrote:
>>>>>> so 64bit could use ioremap_cache() too?
>>>>>> we may keep 32bit and 64bit a bit consistent.
>>>>> If we use ioremap_cache(), kexec runtime service will not work in kexec
>>>>> situation, which needs EFI runtime memory area to be mapped at exact
>>>>> same location across kexec. I think we should support kexec if possible.
>>>> sure.
>>>>
>>>> please don't touch max_low_pfn_mapped, because some range may not
>>>> directly mapped under those efi run-time code
>>> Find an issue to use init_memory_mapping() here.
>>>
>>> If the memory range to be mapped is less than 2M, the last mapped
>>> address may be next 2M aligned position, this may lead mapping
>>> overlapping between memory range. Such as:
>>>
>>> 0x3f388000 - 0x3f488000: real mapped	0x3f388000 - 0x3f600000
>>> 0x3f590000 - 0x3f5bb000: real mapped	0x3f590000 - 0x3f600000
>>>
>>> The problem is that the memory range 0x3f400000 - 0x3f590000 is left not
>>> mapped!
>> what is max_low_pfn_mapped before that?
> 
> I don't know exactly what you mean. Can you elaborate a little?
> 
> 0 ~ max_low_pfn_mapped ~ max_pfn_mapped can be mapped with
> init_memory_mapping() properly.
> 
> The issue of above example is that 0x3f400000 ~ 0x3f488000 is a
> sub-range of 0x3f388000 ~ 0x3f488000, which should be mapped but is left
> not mapped.
what is max_low_pfn_mapped?

what is init_memory_mapping() printout?

YH
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