Re: [Xen-devel] question about machine-to-physic table and phy-to-machine table

[tgh <tianguanhua@xxxxxxxxxx>]

Thank you for your reply

> > I am confused about the meaning and function of  machine-to-physic address
> >     
> it *is* confusing, admittedly. in my understanding, one reaseon for
> 'm2p'/'p2m' being used is that guest operating systems, most prominently
> linux, have always been using 'pfn' for 'page frame number' and the like
> when referring to 'physical' memory. now you need some kind of
> distinction in the paravirtual guest case, because those oses will deal
> with both.
>   
in the paravirt case, guestos maintain its own mfn which need m2p and 
p2m ,is it right?
I am confused about how does guestOS maintain its virt-to-physic and 
physic-to-mach mapping ,in the linux ,there is only v2p mapping, how 
does guestOS maintain its p2m mapping ,and when a virt address is put 
into a mmu, does cpu hardware convert virt-addr into machine address or 
guest's phyiscal address?
I am confused about it

could you help me
Thanks in advance
> that host memory becoming a non-contiguous, non-physical one clearly
> doesn't justify to substitute the names all across the kernel codebase.
> equally, you could not name it virtual or similar in the vmm, because
> the term 'virtual' has obviously been allocated elsewhere.
>
> so host memory became 'machine' memory. in a different universe, it
> might have rather been the actual 'physical' one. or 'host' memory.
> virtual machine memory got a 'p' like in both 'pseudo-physical' and/or
> 'pfn' and i suppose turned for a significant number of people into
> 'physical' at some point. which is largely misleading.
>
> regards,
> daniel
>
>   

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