[PATCH 6/6] KVM: Harden kvm_vcpu_map() against double-mapping and thus leaking references
Sean Christopherson <[email protected]>
| Newsgroups | org.ozlabs.lists.linuxppc-dev,org.kernel.vger.kvm,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
Now that all on-stack maps use CLASS(kvm_vcpu_map_local), i.e. now that all maps are zero-allocated, explicitly put any existing mappings/references when establishing a new mapping to harden against KVM bugs leaking memory, but yell loudly as the owner of the map is still ultimately responsible for the lifecycle of the mapping. Suggested-by: Yosry Ahmed <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> --- virt/kvm/kvm_main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2df8ee9ecf6c..e9e32686e41b 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3118,6 +3118,9 @@ int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map, .pin = true, }; + if (WARN_ON_ONCE(map->hva)) + kvm_vcpu_unmap(vcpu, map); + map->pinned_page = NULL; map->page = NULL; map->hva = NULL; -- 2.55.0.229.g6434b31f56-goog