RE: [Xen-devel] Review needed for "commonisation" ofcommon/grant_table.c

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

>-----Original Message-----
>From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Christopher
>Clark
>Sent: Saturday, June 11, 2005 5:50 AM
>
>
>Why doesn't ia64 use put_page and put_page_type? Isn't there a frame
>table with reference counts on ia64?
>
>Christopher
>
>

Yes, the frame table on ia64 has reference count indeed. We have a
version of put_page/get_page at hand, but not in xeno-unstable-ia64.bk
yet. Will send out the code to Dan soon, to catch up such usage
requirement. ;-)

Now put/get_page_type is same as put/get_page in our patch. The reason
is the difference between x86 and ia64 architecture. On IPF, hardware
doesn't search software managed multi-level page tables directly.
Instead another format VHPT (Virtual Hash Page Table) is walked by
hardware, which is more likely to be considered as cache to TLB.

Currently both para-virtualized and VTI based full virtualization
approaches only virtualizes the TLB, not software page table of guest.
So page type is not meaningful now. Not sure whether there's inevitable
requirement to introduce that complexity on para-virtualized approach in
the future, but it's safe and cleaner to go this way on IA64 now.

Thanks,
Kevin

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