From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Chen, Tiejun" <tiejun.chen@intel.com>
Subject: Re: [v10][PATCH 07/16] hvmloader/e820: construct guest
 e820 table
Date: Mon, 20 Jul 2015 21:23:27 +0800
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To: George Dunlap <dunlapg@umich.edu>
Cc: Keir Fraser <keir@xen.org>, Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Ian Jackson <ian.jackson@eu.citrix.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Jan Beulich <jbeulich@suse.com>, Wei Liu <wei.liu2@citrix.com>
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>> v10:
>>
>> * Instead of correcting e820, I'd like to correct memory_map.map[]
>>    and then copy them into e820 directly. I think this can make sure
>>    hvm_info, memory_map.map[] and e820 are on the same page.
>
> Actually, now that you mention it -- this should probably happen
> instead when we update hvm_info->{low,high}_mem_pgend.

I also considered this point previously but I thought just right now we 
only update hvm_info->low/high_mem_pgend inside pci_setup(). But you 
can't guarantee this would be a sole place in the future. Instead, 
memory_map.map[] would always be copied into e820 when we build e820 table.

So I think we'd better do this update once at the last minute.

Thanks
Tiejun

>
> I'm happy to leave this where it is for now, so with Jan's comments
> addressed (in particular, incrementing nr_map):
>
> Reviewed-by: George Dunlap <george.dunlap@eu.citrix.com>
>
> But if we have time it might be better to pull the loop in pci_setup()
> which moves the memory out into a function, and have that function
> modify the lowmem and highmem map[] entries at the same time we modify
> low_mem_pgend and high_mem_pgend.  Alternately, you could put that on
> your list of clean-ups to hvmloader for 4.7.
>
> Thanks,
>   -George
>