[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] 2.6.20.3 to be the next kernel?
Mark Williamson wrote: > I was wondering how you handle PAE in pv-ops. Presumably you just toggle > based on what the kernel was built for? It seems like PV-ops ought in > principle to be able to make the kernel bimodal. I'm guessing the > appropriate response to my question is probably a simple "patches > welcome" ;-) Indeed. Actually, its something I gave some thought to, but unfortunately it isn't that simple. The main problem is that the types of pte_t/pmd_t/pgd_t change from 32 to 64 bit, and all the pmd folding stuff is still done at compile-time. I was also thinking about always using the PAE forms of the structures, and actually do the conversion just as we read/write the entries. But even then, the various pagetable accessors/traversal functions know how large the entries are and how many levels the pagetables have, etc. The only slightly workable approach I thought of was to maintain a sort-of in-kernel shadow pagetable scheme, which maintains parallel PAE and non-PAE pagetables. But that's hardly elegant, and poses all sorts of its own problems (like propagating the hardware-set access/modified bits properly, for example). So, its all a bit of an open question. J _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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