[RFC 5/8] virtio-ccw: Handle extra notification data

[Jonah Palmer]

Add support to virtio-ccw devices for handling the extra data sent from
the driver to the device when the VIRTIO_F_NOTIFICATION_DATA transport
feature has been negotiated.

The extra data that's passed to the virtio-ccw device when this feature
is enabled varies depending on the device's virtqueue layout.

That data passed to the virtio-ccw device is in the same format as the
data passed to virtio-pci devices.

Signed-off-by: Jonah Palmer <jonah.pal...@oracle.com>
---
 hw/s390x/s390-virtio-ccw.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 62804cc228..b8e193956c 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -140,9 +140,11 @@ static void subsystem_reset(void)
 static int virtio_ccw_hcall_notify(const uint64_t *args)
 {
     uint64_t subch_id = args[0];
-    uint64_t queue = args[1];
+    uint64_t data = args[1];
     SubchDev *sch;
+    VirtIODevice *vdev;
     int cssid, ssid, schid, m;
+    uint16_t vq_idx;
 
     if (ioinst_disassemble_sch_ident(subch_id, &m, &cssid, &ssid, &schid)) {
         return -EINVAL;
@@ -151,12 +153,20 @@ static int virtio_ccw_hcall_notify(const uint64_t *args)
     if (!sch || !css_subch_visible(sch)) {
         return -EINVAL;
     }
-    if (queue >= VIRTIO_QUEUE_MAX) {
+
+    vdev = virtio_ccw_get_vdev(sch);
+    if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFICATION_DATA)) {
+        vq_idx = data & 0xFFFF;
+        virtio_set_notification_data(vdev, vq_idx, data);
+    } else {
+        vq_idx = data;
+    }
+
+    if (vq_idx >= VIRTIO_QUEUE_MAX) {
         return -EINVAL;
     }
-    virtio_queue_notify(virtio_ccw_get_vdev(sch), queue);
+    virtio_queue_notify(vdev, vq_idx);
     return 0;
-
 }
 
 static int virtio_ccw_hcall_early_printk(const uint64_t *args)
-- 
2.39.3