On 06/11/2018 22:05, Barret Rhoden wrote: > On 2018-10-29 at 17:07 Barret Rhoden <b...@google.com> wrote: >> Another issue is that kvm_mmu_zap_collapsible_spte() also uses >> PageTransCompoundMap() to detect huge pages, but we don't have a way to >> get the HVA easily. Can we just aggressively zap DAX pages there? > > Any thoughts about this? Is there a way to determine the HVA or GFN in > this function:
Yes, iter.gfn is the gfn inside the loop and iter.level is the level (1=PTE, 2=PDE, ...). iter.level of course is unusable here, similar to *levelp in transparent_hugepage_adjust, but you can use iter.gfn and gfn_to_hva. Paolo > static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm, > > struct kvm_rmap_head *rmap_head) > > { > u64 *sptep; > > struct rmap_iterator iter; > > int need_tlb_flush = 0; > kvm_pfn_t pfn; > struct kvm_mmu_page *sp; > > > restart: > for_each_rmap_spte(rmap_head, &iter, sptep) { > sp = page_header(__pa(sptep)); > pfn = spte_to_pfn(*sptep); > > /* > * We cannot do huge page mapping for indirect shadow pages, > > * which are found on the last rmap (level = 1) when not > using > * tdp; such shadow pages are synced with the page table in > > * the guest, and the guest page table is using 4K page size > > * mapping if the indirect sp has level = 1. > > */ > if (sp->role.direct && > > !kvm_is_reserved_pfn(pfn) && > > PageTransCompoundMap(pfn_to_page(pfn))) { > > pte_list_remove(rmap_head, sptep); > > need_tlb_flush = 1; > > goto restart; > > } > > } > > return need_tlb_flush; > > } > > If not, I was thinking of changing that loop to always remove PTEs for > DAX mappings, with the understanding that they'll get faulted back in > later. Ideally, we'd like to check if the page is huge, but DAX can't > use the PageTransCompoundMap check. > > Thanks, > > Barret > > > _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm