On Wed, Jun 22, 2022, Paolo Bonzini wrote: > Before allocating a child shadow page table, all callers check > whether the parent already points to a huge page and, if so, they > drop that SPTE. This is done by drop_large_spte(). Thanks for the (), much appreciated! > However, the act that requires dropping the large SPTE is the > installation of the sp that is returned by kvm_mmu_get_child_sp(), > which happens in __link_shadow_page(). Move the call there > instead of having it in each and every caller. > > To ensure that the shadow page is not linked twice if it was > present, do _not_ opportunistically make kvm_mmu_get_child_sp() > idempotent: instead, return an error value if the shadow page > already existed. This is a bit more verbose, but clearer than > NULL. Agreed, and I think we can take advantage of that verbosity to do a tiny bit more cleanup by moving the unsync logic into a wrapper that returns -EAGAIN. Working on a mini-series... > Now that the drop_large_spte() name is not taken anymore, > remove the two underscores in front of __drop_large_spte(). > > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > --- Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
