Re: page table question!

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

some issues are still confuesed ,

Daniel Stodden 写道:
>   
>> then there will not be a small mount of memory consumption for 
>> hyperviser's limited VA ,is it? or where are those counterpart page 
>> tables stored ?
>>     
>
> Or do you mean the part of the VM dedicated to the hypervisor? Code
> running in root mode is running in "host linear" address space, i.e. the
> nested page table, not the guest's one. Actually, that's one major
> benefit of nested paging: counteraction "address space compression".
>   
nested page table ,for the AMD NPT ,is stored in the dom0 linear space, 
not in the hypervisor virtual address ,is it? or what is the meaning of 
"that's one major benefit of nested paging: counteraction "address space 
compression".",and what about the Intel EPT, is it similar ,or how does 
it work, I am still comfused about the hypervisor' limited virtual 
address space, it wont be used for storing the EPT or NPT, is it? or 
what about  the hypervisor's virtual address space in the AMD or 
Intel-vt?how much space is it? or what is tricks behind, could you give 
me a more detailed explanation about NPT and EPT

another one ,"the guest system takes two levels of translation, while 
the host(Xen, in this case) takes only one" , what is the meaning? guest 
does virtual->physical, while physical->machine is translated by xen, is 
it? what is the tricks, by say, guest takes two levels of translation?


Thanks in advance

> So, the guest system takes two levels of translation, while the host
> (Xen, in this case) takes only one.
>
> Hope this helps. Clarify your question if it doesn't.
>
> regards,
> daniel
>
>