On Thu, Jul 01, 2010 at 09:11:36AM +0800, Xiao Guangrong wrote: > > > Marcelo Tosatti wrote: > > >> + > >> + addr = gfn_to_hva_many(vcpu->kvm, gfn, &entry); > >> + if (kvm_is_error_hva(addr)) > >> + return -1; > >> + > >> + entry = min(entry, (int)(end - start)); > >> + ret = __get_user_pages_fast(addr, entry, 1, pages); > >> + if (ret <= 0) > >> + return -1; > > > > Why can't you use gfn_to_pfn_atomic() here, one page at a time? Is > > the overhead significant that this is worthwhile? > > > > You're bypassing the centralized interface. > > I think it's worthwhile to do since we can reduce gup overhead, no reason > to traverse process's page table again and again for the consecutive pages. I'd prefer to use gfn_to_pfn_atomic. The big win is with shadow mode and there its already done one at a time. > > > >> + > >> + pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte); > >> + mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0, > >> + is_dirty_gpte(gpte), NULL, sp->role.level, gfn, > >> + pfn, true, false); > > > > reset_host_protection should be true, see commit 1403283acca (also for > > direct case to be consistent). > > > > Ah, i forgot it, thanks, Marcelo! > > I'll post a small fix patch base on this patchset to change 'false' to 'true' if no > other places no to be improved. :-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
