Messages in this thread | | | Subject | Re: [PATCH V2 3/10] KVM/MMU: Add last_level in the struct mmu_spte_page | From | Paolo Bonzini <> | Date | Fri, 15 Feb 2019 16:22:43 +0100 |
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On 15/02/19 16:05, Tianyu Lan wrote: > Yes, you are right. Thanks to point out and will fix. The last_level > flag is to avoid adding middle page node(e.g, PGD, PMD) > into flush list. The address range will be duplicated if adding both > leaf, node and middle node into flush list.
Hmm, that's not easy to track. One kvm_mmu_page could include both leaf and non-leaf page (for example a huge page for 0 to 2 MB and a page table for 2 MB to 4 MB).
Is this really needed? First, your benchmarks so far have been done with sp->last_level always set to true. Second, you would only encounter this optimization in kvm_mmu_commit_zap_page when zapping a 1 GB region (which then would be invalidated twice, at both the PMD and PGD level) or bigger.
Paolo
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