pc-bios/s390-ccw: add simplified virtio call

Add virtio_run(VirtioCmd) call to use simple declarative approach.
Signed-off-by: NEugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

pc-bios/s390-ccw/virtio.c

@@ -225,6 +225,23 @@ static int vring_wait_reply(void)
     return 1;
 }
 
+int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
+{
+    VRing *vr = &vdev->vrings[vqid];
+    int i = 0;
+
+    do {
+        vring_send_buf(vr, cmd[i].data, cmd[i].size,
+                       cmd[i].flags | (i ? VRING_HIDDEN_IS_CHAIN : 0));
+    } while (cmd[i++].flags & VRING_DESC_F_NEXT);
+
+    vring_wait_reply();
+    if (drain_irqs(vr->schid)) {
+        return -1;
+    }
+    return 0;
+}
+
 /***********************************************
  *               Virtio block                  *
  ***********************************************/

pc-bios/s390-ccw/virtio.h

@@ -248,4 +248,13 @@ typedef struct VDev VDev;
 VDev *virtio_get_device(void);
 VirtioDevType virtio_get_device_type(void);
 
+struct VirtioCmd {
+    void *data;
+    int size;
+    int flags;
+};
+typedef struct VirtioCmd VirtioCmd;
+
+int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd);
+
 #endif /* VIRTIO_H */