On Wed, May 5, 2021 at 2:38 AM Kai Huang <kai.huang@xxxxxxxxx> wrote: > > Currently pf_fixed is increased even when page fault requires emulation, > or fault is spurious. Fix by only increasing it when return value is > RET_PF_FIXED. Revisiting __direct_map and mmu_set_spte, there are cases in the legacy MMU where RET_PF_EMULATE is returned but pf_fixed is still incremented. Perhaps it would make more sense to do the increment in the success case of tdp_mmu_set_spte_atomic as you suggested before. Sorry I didn't catch that earlier. It would probably also be worth putting a comment on pf_fixed so that people in the future know what it's supposed to mean and we don't get into archeology, reverse engineering the meaning of the stat again. > > Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx> > --- > arch/x86/kvm/mmu/tdp_mmu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > index 1cad4c9f7c34..debe8c3ec844 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.c > +++ b/arch/x86/kvm/mmu/tdp_mmu.c > @@ -942,7 +942,7 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, int write, > rcu_dereference(iter->sptep)); > } > > - if (!prefault) > + if (!prefault && ret == RET_PF_FIXED) > vcpu->stat.pf_fixed++; > > return ret; > -- > 2.31.1 >
