kvm: fix MMIO/PIO collision misdetection

PIO and MMIO are separate address spaces, but
ioeventfd registration code mistakenly detected
two eventfds as duplicate if they use the same address,
even if one is PIO and another one MMIO.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

virt/kvm/eventfd.c

@@ -574,6 +574,7 @@ struct _ioeventfd {
 	struct eventfd_ctx  *eventfd;
 	u64                  datamatch;
 	struct kvm_io_device dev;
+	u8                   bus_idx;
 	bool                 wildcard;
 };
 
@@ -666,7 +667,8 @@ ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
 	struct _ioeventfd *_p;
 
 	list_for_each_entry(_p, &kvm->ioeventfds, list)
-		if (_p->addr == p->addr && _p->length == p->length &&
+		if (_p->bus_idx == p->bus_idx &&
+		    _p->addr == p->addr && _p->length == p->length &&
 		    (_p->wildcard || p->wildcard ||
 		     _p->datamatch == p->datamatch))
 			return true;
@@ -723,6 +725,7 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
 
 	INIT_LIST_HEAD(&p->list);
 	p->addr    = args->addr;
+	p->bus_idx = bus_idx;
 	p->length  = args->len;
 	p->eventfd = eventfd;
 
@@ -781,7 +784,8 @@ kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
 	list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
 		bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
 
-		if (p->eventfd != eventfd  ||
+		if (p->bus_idx != bus_idx ||
+		    p->eventfd != eventfd  ||
 		    p->addr != args->addr  ||
 		    p->length != args->len ||
 		    p->wildcard != wildcard)