On Mon, May 06, 2024 at 12:07:33PM +0200, Jan Beulich wrote: > On 30.04.2024 18:58, Roger Pau Monne wrote: > > Keep track of the maximum gfn that has ever been populated into the p2m, and > > also account for the number of foreign mappings. Such information will be > > needed in order to remove foreign mappings during teardown for HVM guests. > > Is "needed" the right term? We could e.g. traverse the P2M tree (didn't look > at patch 2 yet as to how exactly you use these two new fields there), at which > point we might get away without either or both of these extra statistics, > while at the same time also not needing to iterate over a gigantic range of > GFNs. Going from populated page tables would roughly match "max_gfn", with the > benefit of certain removals of P2M entries then also shrinking the upper > bound.
One note about traversing the p2m tree that I forgot to add earlier: AFAICT we would need one implementation for EPT and one for NPT, as I expect the different page-table format won't allow us to use the same code against both EPT and NPT page-tables (I really need to check). Thanks, Roger.
