[Qemu-devel] [PATCH 06/10] virtio-ccw: use vmstate way for config migration

[Halil Pasic <pasic@linux.vnet.ibm.com>]

Let us use the freshly introduced vmstate migration helpers instead of
saving/loading the config manually.

To achieve this we need to hack the config_vector which is a common
VirtIO state in the middle of the VirtioCcwDevice state representation.
This somewhat ugly but we have no choice because the stream format needs
to be preserved.

Still no changes in behavior, but the dead code we added previously is
finally awakening to life.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
---
---
 hw/s390x/virtio-ccw.c | 116 +++++++++++++++++++-------------------------------
 1 file changed, 44 insertions(+), 72 deletions(-)

diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index c2badfe..8ab655c 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -57,6 +57,32 @@ static int virtio_ccw_dev_post_load(void *opaque, int version_id)
     return 0;
 }
 
+static int get_config_vector(QEMUFile *f, void *pv, size_t size,
+                             VMStateField *field)
+{
+    VirtioCcwDevice *dev = pv;
+    VirtIODevice *vdev = virtio_bus_get_device(&dev->bus);
+
+    qemu_get_be16s(f, &vdev->config_vector);
+    return 0;
+}
+
+static int put_config_vector(QEMUFile *f, void *pv, size_t size,
+                             VMStateField *field, QJSON *vmdesc)
+{
+    VirtioCcwDevice *dev = pv;
+    VirtIODevice *vdev = virtio_bus_get_device(&dev->bus);
+
+    qemu_put_be16(f, vdev->config_vector);
+    return 0;
+}
+
+const VMStateInfo vmstate_info_config_vector = {
+    .name = "config_vector",
+    .get = get_config_vector,
+    .put = put_config_vector,
+};
+
 const VMStateDescription vmstate_virtio_ccw_dev = {
     .name = "s390_virtio_ccw_dev",
     .version_id = 1,
@@ -67,6 +93,14 @@ const VMStateDescription vmstate_virtio_ccw_dev = {
         VMSTATE_PTR_TO_IND_ADDR(indicators, VirtioCcwDevice),
         VMSTATE_PTR_TO_IND_ADDR(indicators2, VirtioCcwDevice),
         VMSTATE_PTR_TO_IND_ADDR(summary_indicator, VirtioCcwDevice),
+        {
+        /*
+         * Ugly hack because VirtIODevice does not migrate itself.
+         * This also makes legacy via vmstate_save_state possible.
+         */
+            .name         = "virtio/config_vector",
+            .info         = &vmstate_info_config_vector,
+        },
         VMSTATE_STRUCT(routes, VirtioCcwDevice, 1, vmstate_adapter_routes, \
                        AdapterRoutes),
         VMSTATE_UINT8(thinint_isc, VirtioCcwDevice),
@@ -1272,85 +1306,23 @@ static int virtio_ccw_load_queue(DeviceState *d, int n, QEMUFile *f)
 static void virtio_ccw_save_config(DeviceState *d, QEMUFile *f)
 {
     VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
-    CcwDevice *ccw_dev = CCW_DEVICE(d);
-    SubchDev *s = ccw_dev->sch;
-    VirtIODevice *vdev = virtio_ccw_get_vdev(s);
 
-    subch_device_save(s, f);
-    if (dev->indicators != NULL) {
-        qemu_put_be32(f, dev->indicators->len);
-        qemu_put_be64(f, dev->indicators->addr);
-    } else {
-        qemu_put_be32(f, 0);
-        qemu_put_be64(f, 0UL);
-    }
-    if (dev->indicators2 != NULL) {
-        qemu_put_be32(f, dev->indicators2->len);
-        qemu_put_be64(f, dev->indicators2->addr);
-    } else {
-        qemu_put_be32(f, 0);
-        qemu_put_be64(f, 0UL);
-    }
-    if (dev->summary_indicator != NULL) {
-        qemu_put_be32(f, dev->summary_indicator->len);
-        qemu_put_be64(f, dev->summary_indicator->addr);
-    } else {
-        qemu_put_be32(f, 0);
-        qemu_put_be64(f, 0UL);
-    }
-    qemu_put_be16(f, vdev->config_vector);
-    qemu_put_be64(f, dev->routes.adapter.ind_offset);
-    qemu_put_byte(f, dev->thinint_isc);
-    qemu_put_be32(f, dev->revision);
+    /*
+     * We save in legacy mode. The components take care of their own
+     * compat. representation (based on css_migration_enabled).
+     */
+    vmstate_save_state(f, &vmstate_virtio_ccw_dev, dev, NULL);
 }
 
 static int virtio_ccw_load_config(DeviceState *d, QEMUFile *f)
 {
     VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
-    CcwDevice *ccw_dev = CCW_DEVICE(d);
-    CCWDeviceClass *ck = CCW_DEVICE_GET_CLASS(ccw_dev);
-    SubchDev *s = ccw_dev->sch;
-    VirtIODevice *vdev = virtio_ccw_get_vdev(s);
-    int len;
-
-    s->driver_data = dev;
-    subch_device_load(s, f);
-    /* Re-fill subch_id after loading the subchannel states.*/
-    if (ck->refill_ids) {
-        ck->refill_ids(ccw_dev);
-    }
-    len = qemu_get_be32(f);
-    if (len != 0) {
-        dev->indicators = get_indicator(qemu_get_be64(f), len);
-    } else {
-        qemu_get_be64(f);
-        dev->indicators = NULL;
-    }
-    len = qemu_get_be32(f);
-    if (len != 0) {
-        dev->indicators2 = get_indicator(qemu_get_be64(f), len);
-    } else {
-        qemu_get_be64(f);
-        dev->indicators2 = NULL;
-    }
-    len = qemu_get_be32(f);
-    if (len != 0) {
-        dev->summary_indicator = get_indicator(qemu_get_be64(f), len);
-    } else {
-        qemu_get_be64(f);
-        dev->summary_indicator = NULL;
-    }
-    qemu_get_be16s(f, &vdev->config_vector);
-    dev->routes.adapter.ind_offset = qemu_get_be64(f);
-    dev->thinint_isc = qemu_get_byte(f);
-    dev->revision = qemu_get_be32(f);
-    if (s->thinint_active) {
-        dev->routes.adapter.adapter_id = css_get_adapter_id(
-                                         CSS_IO_ADAPTER_VIRTIO,
-                                         dev->thinint_isc);
-    }
 
-    return 0;
+    /*
+     * We load in legacy mode. The components take take care to read
+     * only stuff which is actually there (based on css_migration_enabled).
+     */
+    return vmstate_load_state(f, &vmstate_virtio_ccw_dev, dev, 1);
 }
 
 static void virtio_ccw_pre_plugged(DeviceState *d, Error **errp)
-- 
2.10.2