Messages in this thread | | | From | Paolo Bonzini <> | Subject | Re: [PATCH 5/6] KVM: x86/mmu: Protect kvm->memslots with a mutex | Date | Wed, 28 Apr 2021 08:25:20 +0200 |
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On 28/04/21 00:36, Ben Gardon wrote: > +void kvm_arch_assign_memslots(struct kvm *kvm, int as_id, > + struct kvm_memslots *slots) > +{ > + mutex_lock(&kvm->arch.memslot_assignment_lock); > + rcu_assign_pointer(kvm->memslots[as_id], slots); > + mutex_unlock(&kvm->arch.memslot_assignment_lock); > +}
Does the assignment also needs the lock, or only the rmap allocation? I would prefer the hook to be something like kvm_arch_setup_new_memslots.
(Also it is useful to have a comment somewhere explaining why the slots_lock does not work. IIUC there would be a deadlock because you'd be taking the slots_lock inside an SRCU critical region, while usually the slots_lock critical section is the one that includes a synchronize_srcu; I should dig that up and document that ordering in Documentation/virt/kvm too).
Paolo
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