pc-bios/s390-ccw/virtio: Add a function to reset a virtio device

To be able to properly silence a virtio device after using it,
we need a global function to reset the device.

Reviewed-by: Jared Rossi <jrossi@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Tested-by: Jared Rossi <jrossi@linux.ibm.com>
Message-ID: <20250116115826.192047-2-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

pc-bios/s390-ccw/virtio.c

@@ -217,6 +217,11 @@ int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
     return 0;
 }
 
+int virtio_reset(VDev *vdev)
+{
+    return run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0, false);
+}
+
 int virtio_setup_ccw(VDev *vdev)
 {
     int i, cfg_size = 0;
@@ -235,7 +240,7 @@ int virtio_setup_ccw(VDev *vdev)
     vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */
     vdev->guessed_disk_nature = VIRTIO_GDN_NONE;
 
-    run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0, false);
+    virtio_reset(vdev);
 
     status = VIRTIO_CONFIG_S_ACKNOWLEDGE;
     if (run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false)) {

pc-bios/s390-ccw/virtio.h

@@ -274,6 +274,7 @@ void vring_send_buf(VRing *vr, void *p, int len, int flags);
 int vr_poll(VRing *vr);
 int vring_wait_reply(void);
 int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd);
+int virtio_reset(VDev *vdev);
 int virtio_setup_ccw(VDev *vdev);
 
 int virtio_net_init(void *mac_addr);