Messages in this thread | | | Date | Wed, 10 Sep 2008 09:38:36 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [Xen-devel] Re: [PATCH 1 of 7] x86: add _PAGE_IOMAP pte flag for IO mappings |
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Avi Kivity wrote: > Actually it's more of a "no struct page" flag, which implies no > refcounting.
Hm, is that actually true enough to define it? Could we rename it something like _PAGE_NOSTRUCTPAGE or something a bit more specific than "special"?
> And not having a struct page should correspond well to a pte not > requiring pfn->mfn conversion and being an I/O page.
But _PAGE_SPECIAL is only set in a few places. It's not set in ioremap mappings and so on. Should it be?
There's also the hiccup that it gets set in a pte with pte_mkspecial() - but at that point its too late because you've already constructed the pte and done the pfn->mfn conversion. _PAGE_IOMAP can only be set when you initially construct the pte out of a frame number and a pgprot.
J
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