[RFC v3 4/8] virtio-pci: implement queue_enabled method

[Cindy Lu <lulu@redhat.com>]

From: Jason Wang <jasowang@redhat.com>

With version 1, we can detect whether a queue is enabled via
queue_enabled.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/virtio-pci.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 4cb784389c..2c82ed5246 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1107,6 +1107,18 @@ static AddressSpace *virtio_pci_get_dma_as(DeviceState *d)
     return pci_get_address_space(dev);
 }
 
+static bool virtio_pci_queue_enabled(DeviceState *d, int n)
+{
+    VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+
+    if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+        return proxy->vqs[vdev->queue_sel].enabled;
+    }
+
+    return virtio_queue_get_desc_addr(vdev, n) != 0;
+}
+
 static int virtio_pci_add_mem_cap(VirtIOPCIProxy *proxy,
                                    struct virtio_pci_cap *cap)
 {
@@ -2059,6 +2071,7 @@ static void virtio_pci_bus_class_init(ObjectClass *klass, void *data)
     k->ioeventfd_enabled = virtio_pci_ioeventfd_enabled;
     k->ioeventfd_assign = virtio_pci_ioeventfd_assign;
     k->get_dma_as = virtio_pci_get_dma_as;
+    k->queue_enabled = virtio_pci_queue_enabled;
 }
 
 static const TypeInfo virtio_pci_bus_info = {
-- 
2.21.1