[Qemu-devel] [PATCH v2 0/7] virtio-blk: use alias properties in transport devices

[Qemu-devel] [PATCH v2 0/7] virtio-blk: use alias properties in transport devices

[Stefan Hajnoczi]

v2:
  * Add qdev_alias_all_properties() instead of virtio-blk-specific function [Paolo]
  * Explain refcount handling in doc comment [Paolo]
  * Fix "property" duplicate typo [Peter Crosthwaite]
  * Add "the same object or" to clarify commit description [Igor]

Thanks for the feedback on the RFC.  This time around the alias property is
implemented at the QOM property level instead of at the qdev property level.

Note that this series only addresses virtio-blk.  In later series we can
convert virtio net, scsi, rng, and serial.

The virtio transport/device split is broken as follows:

1. The virtio-blk device is never finalized because the transport devices
   (virtio-blk-pci and friends) leak the refcount.

2. If we fix the refcount leak then we double-free the 'serial' string property
   upon hot unplug since its char* is copied into the virtio-blk device which
   has an identical 'serial' qdev property.

This series solves both of these problems as follows:

1. Introduce a QOM alias property that lets the transport device forward
   property accesses into the virtio device (the child).

2. Use alias properties in transport devices, instead of keeping a duplicate
   copy of the VirtIOBlkConf struct.

3. Fix the virtio-blk device refcount leak.  It's now safe to do this since the
   double-free has been resolved.

Tested that hotplug/hotunplug of virtio-blk-pci still works.

Stefan Hajnoczi (7):
  qom: add object_property_add_alias()
  virtio-blk: avoid qdev property definition duplication
  virtio-blk: move x-data-plane qdev property to virtio-blk.h
  virtio-blk: use aliases instead of duplicate qdev properties
  virtio-blk: drop virtio_blk_set_conf()
  virtio: fix virtio-blk child refcount in transports
  virtio-blk: move qdev properties into virtio-blk.c

 hw/block/virtio-blk.c          | 18 +++++++++------
 hw/core/qdev.c                 | 19 +++++++++++++++
 hw/s390x/s390-virtio-bus.c     | 10 ++------
 hw/s390x/s390-virtio-bus.h     |  1 -
 hw/s390x/virtio-ccw.c          |  7 ++----
 hw/s390x/virtio-ccw.h          |  1 -
 hw/virtio/virtio-pci.c         |  7 ++----
 hw/virtio/virtio-pci.h         |  1 -
 include/hw/qdev-properties.h   |  2 ++
 include/hw/virtio/virtio-blk.h | 19 ---------------
 include/qom/object.h           | 20 ++++++++++++++++
 qom/object.c                   | 52 ++++++++++++++++++++++++++++++++++++++++++
 12 files changed, 110 insertions(+), 47 deletions(-)

-- 
1.9.0

[Qemu-devel] [PATCH v2 1/7] qom: add object_property_add_alias()

[Stefan Hajnoczi]

Sometimes an object needs to present a property which is actually on
another object, or it needs to provide an alias name for an existing
property.

Examples:
  a.foo -> b.foo
  a.old_name -> a.new_name

The new object_property_add_alias() API allows objects to alias a
property on the same object or another object.  The source and target
names can be different.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
v2:
 * Explain refcount handling in doc comment [Paolo]
 * Fix "property" duplicate typo [Peter Crosthwaite]
 * Add "the same object or" to clarify commit description [Igor]
---
 include/qom/object.h | 20 ++++++++++++++++++++
 qom/object.c         | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/include/qom/object.h b/include/qom/object.h
index a641dcd..854a0d5 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -1203,6 +1203,26 @@ void object_property_add_uint64_ptr(Object *obj, const char *name,
                                     const uint64_t *v, Error **Errp);
 
 /**
+ * object_property_add_alias:
+ * @obj: the object to add a property to
+ * @name: the name of the property
+ * @target_obj: the object to forward property access to
+ * @target_name: the name of the property on the forwarded object
+ * @errp: if an error occurs, a pointer to an area to store the error
+ *
+ * Add an alias for a property on an object.  This function will add a property
+ * of the same type as the forwarded property.
+ *
+ * The caller must ensure that <code>@target_obj</code> stays alive as long as
+ * this property exists.  In the case of a child object or an alias on the same
+ * object this will be the case.  For aliases to other objects the caller is
+ * responsible for taking a reference.
+ */
+void object_property_add_alias(Object *obj, const char *name,
+                               Object *target_obj, const char *target_name,
+                               Error **errp);
+
+/**
  * object_child_foreach:
  * @obj: the object whose children will be navigated
  * @fn: the iterator function to be called
diff --git a/qom/object.c b/qom/object.c
index e42b254..ff50f37 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1515,6 +1515,58 @@ void object_property_add_uint64_ptr(Object *obj, const char *name,
                         NULL, NULL, (void *)v, errp);
 }
 
+typedef struct
+{
+    Object *target_obj;
+    const char *target_name;
+} AliasProperty;
+
+static void property_get_alias(Object *obj, struct Visitor *v, void *opaque,
+                               const char *name, Error **errp)
+{
+    AliasProperty *prop = opaque;
+
+    object_property_get(prop->target_obj, v, prop->target_name, errp);
+}
+
+static void property_set_alias(Object *obj, struct Visitor *v, void *opaque,
+                               const char *name, Error **errp)
+{
+    AliasProperty *prop = opaque;
+
+    object_property_set(prop->target_obj, v, prop->target_name, errp);
+}
+
+static void property_release_alias(Object *obj, const char *name, void *opaque)
+{
+    AliasProperty *prop = opaque;
+
+    g_free(prop);
+}
+
+void object_property_add_alias(Object *obj, const char *name,
+                               Object *target_obj, const char *target_name,
+                               Error **errp)
+{
+    AliasProperty *prop;
+    ObjectProperty *target_prop;
+
+    target_prop = object_property_find(target_obj, target_name, errp);
+    if (!target_prop) {
+        return;
+    }
+
+    prop = g_malloc(sizeof(*prop));
+    prop->target_obj = target_obj;
+    prop->target_name = target_name;
+
+    object_property_add(obj, name, target_prop->type,
+                        property_get_alias,
+                        property_set_alias,
+                        property_release_alias,
+                        prop, errp);
+}
+
 static void object_instance_init(Object *obj)
 {
     object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
-- 
1.9.0

[Qemu-devel] [PATCH v2 2/7] virtio-blk: avoid qdev property definition duplication

[Stefan Hajnoczi]

It becomes unwiedly to duplicate all virtio-blk qdev property
definitions due to an #ifdef.  The C preprocessor syntax makes it a
little hard to resolve this cleanly but we can extract the #ifdef and
call a macro it defines later.

Avoiding duplication is important since it will only get worse when we
move the x-data-plane qdev property here too.  We'd have a combinatorial
explosion since x-data-plane has its own #ifdef.

Suggested-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/virtio/virtio-blk.h | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index e4c41ff..fa416db 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -137,21 +137,19 @@ typedef struct VirtIOBlock {
         DEFINE_VIRTIO_COMMON_FEATURES(_state, _field)
 
 #ifdef __linux__
-#define DEFINE_VIRTIO_BLK_PROPERTIES(_state, _field)                          \
-        DEFINE_BLOCK_PROPERTIES(_state, _field.conf),                         \
-        DEFINE_BLOCK_CHS_PROPERTIES(_state, _field.conf),                     \
-        DEFINE_PROP_STRING("serial", _state, _field.serial),                  \
-        DEFINE_PROP_BIT("config-wce", _state, _field.config_wce, 0, true),    \
-        DEFINE_PROP_BIT("scsi", _state, _field.scsi, 0, true),                \
-        DEFINE_PROP_IOTHREAD("x-iothread", _state, _field.iothread)
+#define DEFINE_VIRTIO_BLK_PROPERTIES_LINUX(_state, _field) \
+        DEFINE_PROP_BIT("scsi", _state, _field.scsi, 0, true),
 #else
+#define DEFINE_VIRTIO_BLK_PROPERTIES_LINUX(_state, _field)
+#endif
+
 #define DEFINE_VIRTIO_BLK_PROPERTIES(_state, _field)                          \
+        DEFINE_VIRTIO_BLK_PROPERTIES_LINUX(_state, _field)                    \
         DEFINE_BLOCK_PROPERTIES(_state, _field.conf),                         \
         DEFINE_BLOCK_CHS_PROPERTIES(_state, _field.conf),                     \
         DEFINE_PROP_STRING("serial", _state, _field.serial),                  \
         DEFINE_PROP_BIT("config-wce", _state, _field.config_wce, 0, true),    \
         DEFINE_PROP_IOTHREAD("x-iothread", _state, _field.iothread)
-#endif /* __linux__ */
 
 void virtio_blk_set_conf(DeviceState *dev, VirtIOBlkConf *blk);
 
-- 
1.9.0

[Qemu-devel] [PATCH v2 3/7] virtio-blk: move x-data-plane qdev property to virtio-blk.h

[Stefan Hajnoczi]

Move the x-data-plane property.  Originally it was outside since not
every transport may wish to support dataplane.  But that makes little
sense when we have a dedicated CONFIG_VIRTIO_BLK_DATA_PLANE ifdef
already.

This move makes it easier to switch to property aliases in the next
patch.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/s390x/virtio-ccw.c          | 3 ---
 hw/virtio/virtio-pci.c         | 3 ---
 include/hw/virtio/virtio-blk.h | 8 ++++++++
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 1cb4e2c..082bb42 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -1129,9 +1129,6 @@ static Property virtio_ccw_blk_properties[] = {
     DEFINE_VIRTIO_BLK_PROPERTIES(VirtIOBlkCcw, blk),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
-#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
-    DEFINE_PROP_BIT("x-data-plane", VirtIOBlkCcw, blk.data_plane, 0, false),
-#endif
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index ce97514..0751a1e 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1067,9 +1067,6 @@ static Property virtio_blk_pci_properties[] = {
     DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
                     VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
-#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
-    DEFINE_PROP_BIT("x-data-plane", VirtIOBlkPCI, blk.data_plane, 0, false),
-#endif
     DEFINE_VIRTIO_BLK_FEATURES(VirtIOPCIProxy, host_features),
     DEFINE_VIRTIO_BLK_PROPERTIES(VirtIOBlkPCI, blk),
     DEFINE_PROP_END_OF_LIST(),
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index fa416db..78e7f81 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -143,8 +143,16 @@ typedef struct VirtIOBlock {
 #define DEFINE_VIRTIO_BLK_PROPERTIES_LINUX(_state, _field)
 #endif
 
+#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
+#define DEFINE_VIRTIO_BLK_PROPERTIES_DATA_PLANE(_state, _field) \
+    DEFINE_PROP_BIT("x-data-plane", _state, _field.data_plane, 0, false),
+#else
+#define DEFINE_VIRTIO_BLK_PROPERTIES_DATA_PLANE(_state, _field)
+#endif
+
 #define DEFINE_VIRTIO_BLK_PROPERTIES(_state, _field)                          \
         DEFINE_VIRTIO_BLK_PROPERTIES_LINUX(_state, _field)                    \
+        DEFINE_VIRTIO_BLK_PROPERTIES_DATA_PLANE(_state, _field)               \
         DEFINE_BLOCK_PROPERTIES(_state, _field.conf),                         \
         DEFINE_BLOCK_CHS_PROPERTIES(_state, _field.conf),                     \
         DEFINE_PROP_STRING("serial", _state, _field.serial),                  \
-- 
1.9.0

[Qemu-devel] [PATCH v2 4/7] virtio-blk: use aliases instead of duplicate qdev properties

[Stefan Hajnoczi]

virtio-blk-pci, virtio-blk-s390, and virtio-blk-ccw all duplicate the
qdev properties of their VirtIOBlock child.  This approach does not work
well with string or pointer properties since we must be careful about
leaking or double-freeing them.

Use the QOM alias property to forward property accesses to the
VirtIOBlock child.  This way no duplication is necessary.

Remember to stop calling virtio_blk_set_conf() so that we don't clobber
the values already set on the VirtIOBlock instance.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
v2:
 * Add qdev_alias_all_properties() instead of virtio-blk-specific
   function [Paolo]
---
 hw/core/qdev.c               | 19 +++++++++++++++++++
 hw/s390x/s390-virtio-bus.c   |  9 +--------
 hw/s390x/s390-virtio-bus.h   |  1 -
 hw/s390x/virtio-ccw.c        |  3 +--
 hw/s390x/virtio-ccw.h        |  1 -
 hw/virtio/virtio-pci.c       |  3 +--
 hw/virtio/virtio-pci.h       |  1 -
 include/hw/qdev-properties.h |  2 ++
 8 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 936eae6..e41f5b8 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -724,6 +724,25 @@ void qdev_property_add_static(DeviceState *dev, Property *prop,
     }
 }
 
+/* @qdev_alias_all_properties - Add alias properties to the source object for
+ * all qdev properties on the target DeviceState.
+ */
+void qdev_alias_all_properties(DeviceState *target, Object *source)
+{
+    ObjectClass *class;
+    Property *prop;
+
+    class = object_get_class(OBJECT(target));
+    do {
+        for (prop = DEVICE_CLASS(class)->props; prop && prop->name; prop++) {
+            object_property_add_alias(source, prop->name,
+                                      OBJECT(target), prop->name,
+                                      &error_abort);
+        }
+        class = object_class_get_parent(class);
+    } while (class != object_class_by_name(TYPE_DEVICE));
+}
+
 static bool device_get_realized(Object *obj, Error **errp)
 {
     DeviceState *dev = DEVICE(obj);
diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
index 9c71afa..041d4e2 100644
--- a/hw/s390x/s390-virtio-bus.c
+++ b/hw/s390x/s390-virtio-bus.c
@@ -179,7 +179,6 @@ static int s390_virtio_blk_init(VirtIOS390Device *s390_dev)
 {
     VirtIOBlkS390 *dev = VIRTIO_BLK_S390(s390_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    virtio_blk_set_conf(vdev, &(dev->blk));
     qdev_set_parent_bus(vdev, BUS(&s390_dev->bus));
     if (qdev_init(vdev) < 0) {
         return -1;
@@ -192,6 +191,7 @@ static void s390_virtio_blk_instance_init(Object *obj)
     VirtIOBlkS390 *dev = VIRTIO_BLK_S390(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
 static int s390_virtio_serial_init(VirtIOS390Device *s390_dev)
@@ -526,18 +526,11 @@ static const TypeInfo s390_virtio_net = {
     .class_init    = s390_virtio_net_class_init,
 };
 
-static Property s390_virtio_blk_properties[] = {
-    DEFINE_VIRTIO_BLK_PROPERTIES(VirtIOBlkS390, blk),
-    DEFINE_PROP_END_OF_LIST(),
-};
-
 static void s390_virtio_blk_class_init(ObjectClass *klass, void *data)
 {
-    DeviceClass *dc = DEVICE_CLASS(klass);
     VirtIOS390DeviceClass *k = VIRTIO_S390_DEVICE_CLASS(klass);
 
     k->init = s390_virtio_blk_init;
-    dc->props = s390_virtio_blk_properties;
 }
 
 static const TypeInfo s390_virtio_blk = {
diff --git a/hw/s390x/s390-virtio-bus.h b/hw/s390x/s390-virtio-bus.h
index ac81bd8..ffd0df7 100644
--- a/hw/s390x/s390-virtio-bus.h
+++ b/hw/s390x/s390-virtio-bus.h
@@ -124,7 +124,6 @@ void s390_virtio_reset_idx(VirtIOS390Device *dev);
 typedef struct VirtIOBlkS390 {
     VirtIOS390Device parent_obj;
     VirtIOBlock vdev;
-    VirtIOBlkConf blk;
 } VirtIOBlkS390;
 
 /* virtio-scsi-s390 */
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 082bb42..f33293d 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -725,7 +725,6 @@ static int virtio_ccw_blk_init(VirtioCcwDevice *ccw_dev)
 {
     VirtIOBlkCcw *dev = VIRTIO_BLK_CCW(ccw_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    virtio_blk_set_conf(vdev, &(dev->blk));
     qdev_set_parent_bus(vdev, BUS(&ccw_dev->bus));
     if (qdev_init(vdev) < 0) {
         return -1;
@@ -739,6 +738,7 @@ static void virtio_ccw_blk_instance_init(Object *obj)
     VirtIOBlkCcw *dev = VIRTIO_BLK_CCW(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
 static int virtio_ccw_serial_init(VirtioCcwDevice *ccw_dev)
@@ -1126,7 +1126,6 @@ static const TypeInfo virtio_ccw_net = {
 static Property virtio_ccw_blk_properties[] = {
     DEFINE_PROP_STRING("devno", VirtioCcwDevice, bus_id),
     DEFINE_VIRTIO_BLK_FEATURES(VirtioCcwDevice, host_features[0]),
-    DEFINE_VIRTIO_BLK_PROPERTIES(VirtIOBlkCcw, blk),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_END_OF_LIST(),
diff --git a/hw/s390x/virtio-ccw.h b/hw/s390x/virtio-ccw.h
index 4393e44..7eea6b9 100644
--- a/hw/s390x/virtio-ccw.h
+++ b/hw/s390x/virtio-ccw.h
@@ -134,7 +134,6 @@ typedef struct VHostSCSICcw {
 typedef struct VirtIOBlkCcw {
     VirtioCcwDevice parent_obj;
     VirtIOBlock vdev;
-    VirtIOBlkConf blk;
 } VirtIOBlkCcw;
 
 /* virtio-balloon-ccw */
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 0751a1e..3bb782f 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1068,7 +1068,6 @@ static Property virtio_blk_pci_properties[] = {
                     VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
     DEFINE_VIRTIO_BLK_FEATURES(VirtIOPCIProxy, host_features),
-    DEFINE_VIRTIO_BLK_PROPERTIES(VirtIOBlkPCI, blk),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -1076,7 +1075,6 @@ static int virtio_blk_pci_init(VirtIOPCIProxy *vpci_dev)
 {
     VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    virtio_blk_set_conf(vdev, &(dev->blk));
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
     if (qdev_init(vdev) < 0) {
         return -1;
@@ -1104,6 +1102,7 @@ static void virtio_blk_pci_instance_init(Object *obj)
     VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
 static const TypeInfo virtio_blk_pci_info = {
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index dc332ae..1cea157 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -131,7 +131,6 @@ struct VHostSCSIPCI {
 struct VirtIOBlkPCI {
     VirtIOPCIProxy parent_obj;
     VirtIOBlock vdev;
-    VirtIOBlkConf blk;
 };
 
 /*
diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
index c46e908..ffef425 100644
--- a/include/hw/qdev-properties.h
+++ b/include/hw/qdev-properties.h
@@ -192,6 +192,8 @@ void error_set_from_qdev_prop_error(Error **errp, int ret, DeviceState *dev,
  */
 void qdev_property_add_static(DeviceState *dev, Property *prop, Error **errp);
 
+void qdev_alias_all_properties(DeviceState *target, Object *source);
+
 /**
  * @qdev_prop_set_after_realize:
  * @dev: device
-- 
1.9.0

[Qemu-devel] [PATCH v2 5/7] virtio-blk: drop virtio_blk_set_conf()

[Stefan Hajnoczi]

This function is no longer used since parent objects now use child
aliases to set the VirtIOBlkConf directly.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/block/virtio-blk.c          | 6 ------
 include/hw/virtio/virtio-blk.h | 2 --
 2 files changed, 8 deletions(-)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 8a568e5..4781351 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -642,12 +642,6 @@ static const BlockDevOps virtio_block_ops = {
     .resize_cb = virtio_blk_resize,
 };
 
-void virtio_blk_set_conf(DeviceState *dev, VirtIOBlkConf *blk)
-{
-    VirtIOBlock *s = VIRTIO_BLK(dev);
-    memcpy(&(s->blk), blk, sizeof(struct VirtIOBlkConf));
-}
-
 #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
 /* Disable dataplane thread during live migration since it does not
  * update the dirty memory bitmap yet.
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 78e7f81..f8d4ac1 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -159,6 +159,4 @@ typedef struct VirtIOBlock {
         DEFINE_PROP_BIT("config-wce", _state, _field.config_wce, 0, true),    \
         DEFINE_PROP_IOTHREAD("x-iothread", _state, _field.iothread)
 
-void virtio_blk_set_conf(DeviceState *dev, VirtIOBlkConf *blk);
-
 #endif
-- 
1.9.0

[Qemu-devel] [PATCH v2 6/7] virtio: fix virtio-blk child refcount in transports

[Stefan Hajnoczi]

object_initialize() leaves the object with a refcount of 1.
object_property_add_child() adds its own reference which is dropped
again when the property is deleted.

The upshot of this is that we always have a refcount >= 1.  Upon hot
unplug the virtio-blk child is not finalized!

Drop our reference after the child property has been added to the
parent.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/s390x/s390-virtio-bus.c | 1 +
 hw/s390x/virtio-ccw.c      | 1 +
 hw/virtio/virtio-pci.c     | 1 +
 3 files changed, 3 insertions(+)

diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
index 041d4e2..bf92cb6 100644
--- a/hw/s390x/s390-virtio-bus.c
+++ b/hw/s390x/s390-virtio-bus.c
@@ -191,6 +191,7 @@ static void s390_virtio_blk_instance_init(Object *obj)
     VirtIOBlkS390 *dev = VIRTIO_BLK_S390(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    object_unref(OBJECT(&dev->vdev));
     qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index f33293d..eb8427b 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -738,6 +738,7 @@ static void virtio_ccw_blk_instance_init(Object *obj)
     VirtIOBlkCcw *dev = VIRTIO_BLK_CCW(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    object_unref(OBJECT(&dev->vdev));
     qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 3bb782f..abf05a9 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1102,6 +1102,7 @@ static void virtio_blk_pci_instance_init(Object *obj)
     VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(obj);
     object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+    object_unref(OBJECT(&dev->vdev));
     qdev_alias_all_properties(DEVICE(&dev->vdev), obj);
 }
 
-- 
1.9.0

[Qemu-devel] [PATCH v2 7/7] virtio-blk: move qdev properties into virtio-blk.c

[Stefan Hajnoczi]

There is no need to make DEFINE_VIRTIO_BLK_PROPERTIES() public.  Inline
it into virtio-blk.c so it cannot be used by mistake from other source
files.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/block/virtio-blk.c          | 12 +++++++++++-
 include/hw/virtio/virtio-blk.h | 23 -----------------------
 2 files changed, 11 insertions(+), 24 deletions(-)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 4781351..3a261c8 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -749,7 +749,17 @@ static void virtio_blk_device_unrealize(DeviceState *dev, Error **errp)
 }
 
 static Property virtio_blk_properties[] = {
-    DEFINE_VIRTIO_BLK_PROPERTIES(VirtIOBlock, blk),
+    DEFINE_BLOCK_PROPERTIES(VirtIOBlock, blk.conf),
+    DEFINE_BLOCK_CHS_PROPERTIES(VirtIOBlock, blk.conf),
+    DEFINE_PROP_STRING("serial", VirtIOBlock, blk.serial),
+    DEFINE_PROP_BIT("config-wce", VirtIOBlock, blk.config_wce, 0, true),
+    DEFINE_PROP_IOTHREAD("x-iothread", VirtIOBlock, blk.iothread),
+#ifdef __linux__
+    DEFINE_PROP_BIT("scsi", VirtIOBlock, blk.scsi, 0, true),
+#endif
+#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
+    DEFINE_PROP_BIT("x-data-plane", VirtIOBlock, blk.data_plane, 0, false),
+#endif
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index f8d4ac1..beecb7e 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -136,27 +136,4 @@ typedef struct VirtIOBlock {
 #define DEFINE_VIRTIO_BLK_FEATURES(_state, _field) \
         DEFINE_VIRTIO_COMMON_FEATURES(_state, _field)
 
-#ifdef __linux__
-#define DEFINE_VIRTIO_BLK_PROPERTIES_LINUX(_state, _field) \
-        DEFINE_PROP_BIT("scsi", _state, _field.scsi, 0, true),
-#else
-#define DEFINE_VIRTIO_BLK_PROPERTIES_LINUX(_state, _field)
-#endif
-
-#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
-#define DEFINE_VIRTIO_BLK_PROPERTIES_DATA_PLANE(_state, _field) \
-    DEFINE_PROP_BIT("x-data-plane", _state, _field.data_plane, 0, false),
-#else
-#define DEFINE_VIRTIO_BLK_PROPERTIES_DATA_PLANE(_state, _field)
-#endif
-
-#define DEFINE_VIRTIO_BLK_PROPERTIES(_state, _field)                          \
-        DEFINE_VIRTIO_BLK_PROPERTIES_LINUX(_state, _field)                    \
-        DEFINE_VIRTIO_BLK_PROPERTIES_DATA_PLANE(_state, _field)               \
-        DEFINE_BLOCK_PROPERTIES(_state, _field.conf),                         \
-        DEFINE_BLOCK_CHS_PROPERTIES(_state, _field.conf),                     \
-        DEFINE_PROP_STRING("serial", _state, _field.serial),                  \
-        DEFINE_PROP_BIT("config-wce", _state, _field.config_wce, 0, true),    \
-        DEFINE_PROP_IOTHREAD("x-iothread", _state, _field.iothread)
-
 #endif
-- 
1.9.0