Re: PV guest + shadow paging

[tgh <tianguanhua@ncic.ac.cn>]

hi
what is the auto_translated_physmap ?how does it work?and what about 
other mechanisms and how many mechanisms for paging are there in xen ?

Thank you in advance


Tim Deegan 写道:
> At 07:34 +0100 on 30 Jul (1185780899), Ian Campbell wrote:
>   
>> Adding
>>         features = "auto_translated_physmap|writable_page_tables"
>> to the config file should add those features to the set passed to the
>> guest. I can't remember which set you would need to enable shadow mode,
>> you may have to dig round in the builder and/or hypervisor to figure it
>> out.
>>     
>
> IIRC, "auto_translated_physmap" turns on both shadow mode and
> auto-translation.  You could enable just the shadowing without the
> auto-translation by changing tools/libxc/xc_dom_x86.c to remove
> XEN_DOMCTL_SHADOW_ENABLE_TRANSLATE from the "mode" argument to
> xc_shadow_control().
>
>   
>> However I'm not sure shadow mode (other than log-dirty) isn't broken for
>> PV guests. It's been a long time since I tried it but it was broken back
>> when the paravirt_ops tree was still trying to use it.
>>     
>
> Auto-translate was (briefly) fixed at that time too, but I'm quite sure
> it doesn't work in the current tree.  Some people had this kind of thing
> going for academic research projects; maybe one of them can comment.
>
> Cheers,
>
> Tim.
>
>