[Qemu-devel] [PATCH v2 5/5] virtio: add "use-started" property

[elohimes]

From: Xie Yongji <address@hidden>

In order to avoid migration issues, we introduce a "use-started"
property to the base virtio device to indicate whether use
"started" flag or not. This property will be true by default and
set to false when machine type <= 4.0.1.

Signed-off-by: Xie Yongji <address@hidden>
---
 hw/block/vhost-user-blk.c  |  4 ++--
 hw/core/machine.c          |  4 +++-
 hw/virtio/virtio.c         | 21 ++++++++-------------
 include/hw/virtio/virtio.h | 21 +++++++++++++++++++++
 4 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index 9cb61336a6..85bc4017e7 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -191,7 +191,7 @@ static void vhost_user_blk_stop(VirtIODevice *vdev)
 static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
-    bool should_start = vdev->started;
+    bool should_start = virtio_device_started(vdev, status);
     int ret;
 
     if (!vdev->vm_running) {
@@ -317,7 +317,7 @@ static int vhost_user_blk_connect(DeviceState *dev)
     }
 
     /* restore vhost state */
-    if (vdev->started) {
+    if (virtio_device_started(vdev, vdev->status)) {
         ret = vhost_user_blk_start(vdev);
         if (ret < 0) {
             error_report("vhost-user-blk: vhost start failed: %s",
diff --git a/hw/core/machine.c b/hw/core/machine.c
index f1a0f45f9c..133c113ebf 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -24,7 +24,9 @@
 #include "hw/pci/pci.h"
 #include "hw/mem/nvdimm.h"
 
-GlobalProperty hw_compat_4_0_1[] = {};
+GlobalProperty hw_compat_4_0_1[] = {
+    { "virtio-device", "use-started", "false" },
+};
 const size_t hw_compat_4_0_1_len = G_N_ELEMENTS(hw_compat_4_0_1);
 
 GlobalProperty hw_compat_4_0[] = {};
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 3960619bd4..9af2e339af 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1165,10 +1165,7 @@ int virtio_set_status(VirtIODevice *vdev, uint8_t val)
 
     if ((vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) !=
         (val & VIRTIO_CONFIG_S_DRIVER_OK)) {
-        vdev->started = val & VIRTIO_CONFIG_S_DRIVER_OK;
-        if (unlikely(vdev->start_on_kick && vdev->started)) {
-            vdev->start_on_kick = false;
-        }
+        virtio_set_started(vdev, val & VIRTIO_CONFIG_S_DRIVER_OK);
     }
 
     if (k->set_status) {
@@ -1539,8 +1536,7 @@ static bool virtio_queue_notify_aio_vq(VirtQueue *vq)
         ret = vq->handle_aio_output(vdev, vq);
 
         if (unlikely(vdev->start_on_kick)) {
-            vdev->started = true;
-            vdev->start_on_kick = false;
+            virtio_set_started(vdev, true);
         }
     }
 
@@ -1560,8 +1556,7 @@ static void virtio_queue_notify_vq(VirtQueue *vq)
         vq->handle_output(vdev, vq);
 
         if (unlikely(vdev->start_on_kick)) {
-            vdev->started = true;
-            vdev->start_on_kick = false;
+            virtio_set_started(vdev, true);
         }
     }
 }
@@ -1581,8 +1576,7 @@ void virtio_queue_notify(VirtIODevice *vdev, int n)
         vq->handle_output(vdev, vq);
 
         if (unlikely(vdev->start_on_kick)) {
-            vdev->started = true;
-            vdev->start_on_kick = false;
+            virtio_set_started(vdev, true);
         }
     }
 }
@@ -2083,7 +2077,7 @@ int virtio_set_features(VirtIODevice *vdev, uint64_t val)
             }
         }
 
-        if (!vdev->started &&
+        if (!virtio_device_started(vdev, vdev->status) &&
             !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
             vdev->start_on_kick = true;
         }
@@ -2238,7 +2232,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int 
version_id)
         }
     }
 
-    if (!vdev->started &&
+    if (!virtio_device_started(vdev, vdev->status) &&
         !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
         vdev->start_on_kick = true;
     }
@@ -2306,7 +2300,7 @@ static void virtio_vmstate_change(void *opaque, int 
running, RunState state)
     VirtIODevice *vdev = opaque;
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
-    bool backend_run = running && vdev->started;
+    bool backend_run = running && virtio_device_started(vdev, vdev->status);
     vdev->vm_running = running;
 
     if (backend_run) {
@@ -2683,6 +2677,7 @@ static void virtio_device_instance_finalize(Object *obj)
 
 static Property virtio_properties[] = {
     DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
+    DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 303242b3c2..b189788cb2 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -105,6 +105,7 @@ struct VirtIODevice
     uint16_t device_id;
     bool vm_running;
     bool broken; /* device in invalid state, needs reset */
+    bool use_started;
     bool started;
     bool start_on_kick; /* when virtio 1.0 feature has not been negotiated */
     VMChangeStateEntry *vmstate;
@@ -351,4 +352,24 @@ static inline bool virtio_is_big_endian(VirtIODevice *vdev)
     /* Devices conforming to VIRTIO 1.0 or later are always LE. */
     return false;
 }
+
+static inline bool virtio_device_started(VirtIODevice *vdev, uint8_t status)
+{
+    if (vdev->use_started) {
+        return vdev->started;
+    }
+
+    return status & VIRTIO_CONFIG_S_DRIVER_OK;
+}
+
+static inline void virtio_set_started(VirtIODevice *vdev, bool started)
+{
+    if (started) {
+        vdev->start_on_kick = false;
+    }
+
+    if (vdev->use_started) {
+        vdev->started = started;
+    }
+}
 #endif
-- 
2.17.1