Xen devel - Oct 2005 - misleading names in xen memory management code

Keir, I think we have some misleading names in xen memory management
code:
1) #define page_to_pfn(_page)  ((unsigned long)((_page) - frame_table))
Actually, it should be page_to_mfn.

2) #define l1e_from_pfn(pfn, flags)   \
    ((l1_pgentry_t) { ((intpte_t)(pfn) << PAGE_SHIFT) |
put_pte_flags(flags) })
Seems l1e_from_mfn(mfn, flags) is much more clear.

Am I right?

-Xin


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> Keir, I think we have some misleading names in xen memory management
> code:
> 1) #define page_to_pfn(_page)  ((unsigned long)((_page) - 
> frame_table)) Actually, it should be page_to_mfn.
> 
> 2) #define l1e_from_pfn(pfn, flags)   \
>     ((l1_pgentry_t) { ((intpte_t)(pfn) << PAGE_SHIFT) |
> put_pte_flags(flags) })
> Seems l1e_from_mfn(mfn, flags) is much more clear.
> 
> Am I right?
Yep, these are functions from the very early days of Xen, before the
terminology was properly developed. They could usefully be renamed.

While doing this, it would be well worth paying attention to uses of
page_to_pfn to check that the value returned is never shifted left
PAGE_SHIFT without appropriate casting (for PAE).


Ian

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