linux-kernel - Re: [PATCH] x86: extend e820 ealy_res support 32bit

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Date:	Thu, 29 May 2008 12:14:20 -0700
From:	"Yinghai Lu" <yhlu.kernel@...il.com>
To:	"Jeremy Fitzhardinge" <jeremy@...p.org>
Cc:	"Rusty Russell" <rusty@...tcorp.com.au>,
	"Thomas Gleixner" <tglx@...utronix.de>,
	"Ingo Molnar" <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: extend e820 ealy_res support 32bit - fix #2

On Thu, May 29, 2008 at 11:52 AM, Yinghai Lu <yhlu.kernel@...il.com> wrote:
> On Thu, May 29, 2008 at 6:37 AM, Jeremy Fitzhardinge <jeremy@...p.org> wrote:
>> Yinghai Lu wrote:
>>>
>>> can we use e820 entries for that? So the domain builder could have
>>> several entries for E820_RAM and E820_RESERVED...
>>>
>>
>> I tried this, but it doesn't work; the kernel crashes during boot,
>> presumably because it's trying to use the reserved memory as heap.  I
>> suspect the e820 maps are not registered early enough or something...
>>
>> (One thought: if reserving in the E820 map were enough, then couldn't we use
>> it for all the early reservations?)
>>
>> I've attached the non-working patch below.
>>
>> The working kernel reports:
>>
>> (early) BIOS-provided physical RAM map:
>> (early)  Xen: 0000000000000000 - 000000000009f000 (usable)
>> (early)  Xen: 0000000000100000 - 0000000010000000 (usable)
>> (early) console [xenboot0] enabled
>> (early) debug: ignoring loglevel setting.
>> (early) 0MB HIGHMEM available.
>> (early) 256MB LOWMEM available.
>> (early)   low ram: 018fd000 - 10000000
>> (early)   bootmap 018fd000 - 018ff000
>> (early)   early res: 0 [0-fff] BIOS data page
>> (early)   early res: 1 [1000-1fff] EX TRAMPOLINE
>> (early)   early res: 2 [6000-6fff] TRAMPOLINE
>> (early)   early res: 3 [18aa000-18ecfff] XEN
>> (early)   early res: 4 [1000000-18a9303] TEXT DATA BSS
>> (early)   early res: 5 [18ed000-18fcfff] INIT_PG_TABLE
>> (early)   early res: 6 [18fd000-18fefff] BOOTMAP
>>
>> But the non-working one says:
>>
>> (early) BIOS-provided physical RAM map:
>> (early)  Xen: 0000000000000000 - 000000000009f000 (usable)
>> (early)  Xen: 0000000000100000 - 0000000010000000 (usable)
>> (early)  Xen: 00000000018aa000 - 00000000018ed000 (reserved)
>
> it seems we miss to call sanitize_e820_map for 32 bit. we should get
> (early)  Xen: 0000000000000000 - 000000000009f000 (usable)
> (early)  Xen: 0000000000100000 - 00000000018aa000 (usable)
> (early)  Xen: 00000000018aa000 - 00000000018ed000 (reserved)
> (early)  Xen: 00000000018ed000 - 0000000010000000 (usable)

xen pv override the memory_setup. and default one is
machine_specific_memory_setup(), and it does call sanitize_e820_map...

so you may need to add sanitize_e820_map to xen_memory_setup, or re
arrange your add_memory_range parameter...

YH
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