[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] Re: [PATCH 1 of 7] x86: add _PAGE_IOMAP pte flag for IO mappings

Avi Kivity wrote:

I'm not sure; I still don't really understand how _PAGE_SPECIAL gets
used, other than being user-mode mapping only.  But in principle,
_PAGE_IOMAP could be set on both kernel and user mappings (if you direct
map a device into a process address space), so I think they would
conflict then?

It's a "don't refcount me" flag, which is not sematically the same as I/O, but may be close enough.

Actually it's more of a "no struct page" flag, which implies no refcounting. And not having a struct page should correspond well to a pte not requiring pfn->mfn conversion and being an I/O page.

error compiling committee.c: too many arguments to function

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.