Re: [v10][PATCH 07/16] hvmloader/e820: construct guest e820 table

["Chen, Tiejun" <tiejun.chen@intel.com>]

>>> 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.
>
> We can guarantee it, if nothing else by making sure that no new
> changes are added which change the one but not the other.

This means you have to syn this again once you change hvm_info so I 
think this may cost a little bit.

Thanks
Tiejun

>
> But perhaps better would be to put a check in build_e820_map() to
> BUG() if hvm_info and memory_map are out of sync.
>
> On the other hand, looking at this now, I think that long-term we
> should probably move to have *all* information about the memory layout
> passed to hvmloader via the memory map, rather than via hvm_info.
> That way we can also get rid of the "magic" knowledge that hvmloader
> has about the memory layout (e.g., the VGA hole).
>
>   -George
>