virtio-ccw: Handle extra notification data

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.palmer@oracle.com>
Message-Id: <20240315165557.26942-5-jonah.palmer@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index cd063f8b645917046f969b7649716158696cc09d..8cd912f20e4651b4c42c7366ac04d5faed82ee80 100644 (file)
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -126,9 +126,11 @@ 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 = data;
 
     if (ioinst_disassemble_sch_ident(subch_id, &m, &cssid, &ssid, &schid)) {
         return -EINVAL;
@@ -137,12 +139,19 @@ 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 (vq_idx >= VIRTIO_QUEUE_MAX || !virtio_queue_get_num(vdev, vq_idx)) {
         return -EINVAL;
     }
-    virtio_queue_notify(virtio_ccw_get_vdev(sch), queue);
-    return 0;
 
+    if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFICATION_DATA)) {
+        virtio_queue_set_shadow_avail_idx(virtio_get_queue(vdev, vq_idx),
+                                          (data >> 16) & 0xFFFF);
+    }
+
+    virtio_queue_notify(vdev, vq_idx);
+    return 0;
 }
 
 static int virtio_ccw_hcall_early_printk(const uint64_t *args)