[PULL 13/35] virtio-bus: introduce iommu_enabled()

["Michael S. Tsirkin" <mst@redhat.com>]

From: Jason Wang <jasowang@redhat.com>

This patch introduce a new method for the virtio-bus for the transport
to report whether or not the IOMMU is enabled for the device.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20210804034803.1644-2-jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/hw/virtio/virtio-bus.h |  4 +++-
 hw/virtio/virtio-bus.c         | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/include/hw/virtio/virtio-bus.h b/include/hw/virtio/virtio-bus.h
index ef8abe49c5..7ab8c9dab0 100644
--- a/include/hw/virtio/virtio-bus.h
+++ b/include/hw/virtio/virtio-bus.h
@@ -93,6 +93,7 @@ struct VirtioBusClass {
      */
     bool has_variable_vring_alignment;
     AddressSpace *(*get_dma_as)(DeviceState *d);
+    bool (*iommu_enabled)(DeviceState *d);
 };
 
 struct VirtioBusState {
@@ -154,5 +155,6 @@ void virtio_bus_release_ioeventfd(VirtioBusState *bus);
 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign);
 /* Tell the bus that the ioeventfd handler is no longer required. */
 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n);
-
+/* Whether the IOMMU is enabled for this device */
+bool virtio_bus_device_iommu_enabled(VirtIODevice *vdev);
 #endif /* VIRTIO_BUS_H */
diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
index 859978d248..d23db98c56 100644
--- a/hw/virtio/virtio-bus.c
+++ b/hw/virtio/virtio-bus.c
@@ -325,6 +325,20 @@ static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
     return NULL;
 }
 
+bool virtio_bus_device_iommu_enabled(VirtIODevice *vdev)
+{
+    DeviceState *qdev = DEVICE(vdev);
+    BusState *qbus = BUS(qdev_get_parent_bus(qdev));
+    VirtioBusState *bus = VIRTIO_BUS(qbus);
+    VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
+
+    if (!klass->iommu_enabled) {
+        return false;
+    }
+
+    return klass->iommu_enabled(qbus->parent);
+}
+
 static void virtio_bus_class_init(ObjectClass *klass, void *data)
 {
     BusClass *bus_class = BUS_CLASS(klass);
-- 
MST