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But given that > deleting the vCPU from the array Just Works, adding logic to the requests > path is unnecessary, and trying to make requests illegal during teardown > would be a fool's errand. > > Signed-off-by: Sean Christopherson > --- > virt/kvm/kvm_main.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 201c14ff476f..991e8111e88b 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -489,6 +489,14 @@ void kvm_destroy_vcpus(struct kvm *kvm) > kvm_for_each_vcpu(i, vcpu, kvm) { > kvm_vcpu_destroy(vcpu); > xa_erase(&kvm->vcpu_array, i); > + > + /* > + * Assert that the vCPU isn't visible in any way, to ensure KVM > + * doesn't trigger a use-after-free if destroying vCPUs results > + * in VM-wide request, e.g. to flush remote TLBs when tearing > + * down MMUs, or to mark the VM dead if a KVM_BUG_ON() fires. > + */ > + WARN_ON_ONCE(xa_load(&kvm->vcpu_array, i) || kvm_get_vcpu(kvm, i)); As xa_erase() says "After this function returns, loading from @index will return %NULL", is this checking of xa_load() necessary? > } > > atomic_set(&kvm->online_vcpus, 0); > -- > 2.48.1.658.g4767266eb4-goog >