Messages in this thread | | | Date | Thu, 23 Jun 2022 23:48:30 +0000 | From | Sean Christopherson <> | Subject | Re: [PATCH v7 20/23] KVM: x86/mmu: pull call to drop_large_spte() into __link_shadow_page() |
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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@redhat.com> > ---
Reviewed-by: Sean Christopherson <seanjc@google.com>
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