Messages in this thread | | | Date | Fri, 12 Apr 2024 13:44:41 -0700 | From | David Matlack <> | Subject | Re: [PATCH v3 5/7] KVM: x86: Participate in bitmap-based PTE aging |
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On 2024-04-01 11:29 PM, James Houghton wrote: > Only handle the TDP MMU case for now. In other cases, if a bitmap was > not provided, fallback to the slowpath that takes mmu_lock, or, if a > bitmap was provided, inform the caller that the bitmap is unreliable.
I think this patch will trigger a lockdep assert in
kvm_tdp_mmu_age_gfn_range kvm_tdp_mmu_handle_gfn for_each_tdp_mmu_root __for_each_tdp_mmu_root kvm_lockdep_assert_mmu_lock_held
.. because it walks tdp_mmu_roots without holding mmu_lock.
Yu's patch[1] added a lockless walk to the TDP MMU. We'd need something similar here and also update the comment above tdp_mmu_roots describing how tdp_mmu_roots can be read locklessly.
[1] https://lore.kernel.org/kvmarm/ZItX64Bbx5vdjo9M@google.com/
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