kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd

We only want zero length mmio eventfd to be registered on
KVM_FAST_MMIO_BUS. So check this explicitly when arg->len is zero to
make sure this.

Cc: stable@vger.kernel.org
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 9ff4193dfa493c3e226c3fd554061b171ca7b9c5..e404806e3a7afc7901c7c057737f163afaeffac6 100644 (file)
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -846,7 +846,7 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
        /* When length is ignored, MMIO is also put on a separate bus, for
         * faster lookups.
         */
-       if (!args->len && !(args->flags & KVM_IOEVENTFD_FLAG_PIO)) {
+       if (!args->len && bus_idx == KVM_MMIO_BUS) {
                ret = kvm_io_bus_register_dev(kvm, KVM_FAST_MMIO_BUS,
                                              p->addr, 0, &p->dev);
                if (ret < 0)
@@ -901,7 +901,7 @@ kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
                        continue;
 
                kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
-               if (!p->length) {
+               if (!p->length && p->bus_idx == KVM_MMIO_BUS) {
                        kvm_io_bus_unregister_dev(kvm, KVM_FAST_MMIO_BUS,
                                                  &p->dev);
                }