On Monday 19 Jul 2021 at 13:55:29 (+0100), Marc Zyngier wrote: > On Mon, 19 Jul 2021 11:47:26 +0100, > Quentin Perret <qperret@xxxxxxxxxx> wrote: > > > > The nVHE protected mode uses invalid mappings in the host stage-2 > > page-table to track the owner of each page in the system. In order to > > allow the usage of ignored bits (a.k.a. software bits) in these > > mappings, move the owner encoding away from the top bits. > > But that's exactly what the current situation is allowing: the use of > the SW bits. I am guessing that what you really mean is that you want > to *preserve* the SW bits from an existing mapping and use other bits > when the mapping is invalid? Yes, this is really just forward looking, but I think it might be useful to allow annotating invalid mappings with both an owner id _and_ additional flags for e.g. shared pages and such. And using bits [58-55] to store those flags just like we do for valid mappings should make things easier, but no big deal. I see how this is going to conflict with kvm_pgtable_stage2_annotate() from your series though, so maybe I should just drop this patch and leave the encoding 'issue' to the caller -- the rest of the series doesn't depend on this anyway, this was just small cleanup. Thanks, Quentin _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
