On Wed, Nov 10, 2021, Ben Gardon wrote: > In the interest of devloping a version of make_spte that can function > without a vCPU pointer, factor out the shadow_zero_mask to be an > additional argument to the function. > > No functional change intended. > > > Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx> > --- > arch/x86/kvm/mmu/spte.c | 11 +++++++---- > arch/x86/kvm/mmu/spte.h | 3 ++- > 2 files changed, 9 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c > index b7271daa06c5..d3b059e96c6e 100644 > --- a/arch/x86/kvm/mmu/spte.c > +++ b/arch/x86/kvm/mmu/spte.c > @@ -93,7 +93,8 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, > struct kvm_memory_slot *slot, unsigned int pte_access, > gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool prefetch, > bool can_unsync, bool host_writable, bool ad_need_write_protect, > - u64 mt_mask, u64 *new_spte) > + u64 mt_mask, struct rsvd_bits_validate *shadow_zero_check, Ugh, so I had a big email written about how I think we should add a module param to control 4-level vs. 5-level for all TDP pages, but then I realized it wouldn't work for nested EPT because that follows the root level used by L1. We could still make a global non_nested_tdp_shadow_zero_check or whatever, but then make_spte() would have to do some work to find the right rsvd_bits_validate, and the end result would likely be a mess. One idea to avoid exploding make_spte() would be to add a backpointer to the MMU in kvm_mmu_page. I don't love the idea, but I also don't love passing in rsvd_bits_validate.
