On Fri, Sep 25, 2020 at 02:22:49PM -0700, Ben Gardon wrote: > In order to avoid creating executable hugepages in the TDP MMU PF > handler, remove the dependency between disallowed_hugepage_adjust and > the shadow_walk_iterator. This will open the function up to being used > by the TDP MMU PF handler in a future patch. > > Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell > machine. This series introduced no new failures. > > This series can be viewed in Gerrit at: > https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 > > Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx> > --- > arch/x86/kvm/mmu/mmu.c | 17 +++++++++-------- > arch/x86/kvm/mmu/paging_tmpl.h | 3 ++- > 2 files changed, 11 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 6344e7863a0f5..f6e6fc9959c04 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -3295,13 +3295,12 @@ static int kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, gfn_t gfn, > return level; > } > > -static void disallowed_hugepage_adjust(struct kvm_shadow_walk_iterator it, > - gfn_t gfn, kvm_pfn_t *pfnp, int *levelp) > +static void disallowed_hugepage_adjust(u64 spte, gfn_t gfn, int cur_level, > + kvm_pfn_t *pfnp, int *goal_levelp) > { > - int level = *levelp; > - u64 spte = *it.sptep; > + int goal_level = *goal_levelp; More bikeshedding... Can we keep 'level' and 'levelp' instead of prepending 'goal_'? I get the intent, but goal_level isn't necessarily accurate as the original requested level (referred to as req_level in the caller in kvm/queue) may be different than goal_level, i.e. this helper may have already decremented the level. IMO it's more accurate/correct to keep the plain 'level'. > - if (it.level == level && level > PG_LEVEL_4K && > + if (cur_level == goal_level && goal_level > PG_LEVEL_4K && > is_nx_huge_page_enabled() && > is_shadow_present_pte(spte) && > !is_large_pte(spte)) { > @@ -3312,9 +3311,10 @@ static void disallowed_hugepage_adjust(struct kvm_shadow_walk_iterator it, > * patching back for them into pfn the next 9 bits of > * the address. > */ > - u64 page_mask = KVM_PAGES_PER_HPAGE(level) - KVM_PAGES_PER_HPAGE(level - 1); > + u64 page_mask = KVM_PAGES_PER_HPAGE(goal_level) - > + KVM_PAGES_PER_HPAGE(goal_level - 1); > *pfnp |= gfn & page_mask; > - (*levelp)--; > + (*goal_levelp)--; > } > } > > @@ -3339,7 +3339,8 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t gpa, int write, > * We cannot overwrite existing page tables with an NX > * large page, as the leaf could be executable. > */ > - disallowed_hugepage_adjust(it, gfn, &pfn, &level); > + disallowed_hugepage_adjust(*it.sptep, gfn, it.level, > + &pfn, &level); > > base_gfn = gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1); > if (it.level == level) > diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h > index 4dd6b1e5b8cf7..6a8666cb0d24b 100644 > --- a/arch/x86/kvm/mmu/paging_tmpl.h > +++ b/arch/x86/kvm/mmu/paging_tmpl.h > @@ -690,7 +690,8 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gpa_t addr, > * We cannot overwrite existing page tables with an NX > * large page, as the leaf could be executable. > */ > - disallowed_hugepage_adjust(it, gw->gfn, &pfn, &hlevel); > + disallowed_hugepage_adjust(*it.sptep, gw->gfn, it.level, > + &pfn, &hlevel); > > base_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1); > if (it.level == hlevel) > -- > 2.28.0.709.gb0816b6eb0-goog >
