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virtio: make bindings typesafe

PATCH New Michael S. Tsirkin 1 participant 1 message Dec 18, 2012

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Michael S. Tsirkin

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PATCH v3 1/1 virtio: make bindings typesafe

Move bindings from opaque to DeviceState.
This gives us better type safety with no performance cost. Add macros to make future QOM work easier.
Note: this code is not replacing QOM use with non QOM - it is replacing unsafe void * use with type-checked use. Switch of the implementation to QOM where feasible can be done by a follow-up patch.

Signed-off-by Michael S. Tsirkin <[email protected]>

---

Changes from v2:
- More comments by Anreas F\344rber:
Document which code is datapath, create wrapper to make future QOM changes easier.
- Address comment by Anthony:
use inline functions for type safety and to avoid conflicting with QOM
Changes from v1:
- Address comment by Anreas F\344rber: wrap container_of macros to make future QOM work easier
- make a couple of bindings that v1 missed typesafe:
virtio doesn't use any void * now

hw/s390-virtio-bus.c +19 -5
index e0ac2d1..8570b76 100644
@@ -137,7 +137,7 @@ static int s390_virtio_device_init(VirtIOS390Device *dev, VirtIODevice *vdev)
 
     bus->dev_offs += dev_len;
 
-    virtio_bind_device(vdev, &virtio_s390_bindings, dev);
+    virtio_bind_device(vdev, &virtio_s390_bindings, DEVICE(dev));
     dev->host_features = vdev->get_features(vdev, dev->host_features);
     s390_virtio_device_sync(dev);
     s390_virtio_reset_idx(dev);

@@ -364,9 +364,23 @@ VirtIOS390Device *s390_virtio_bus_find_mem(VirtIOS390Bus *bus, ram_addr_t mem)
     return NULL;
 }
 
-static void virtio_s390_notify(void *opaque, uint16_t vector)
+/* DeviceState to VirtIOS390Device. Note: used on datapath,
+ * be careful and test performance if you change this.
+ */
+static inline VirtIOS390Device *to_virtio_s390_device_fast(DeviceState *d)
+{
+    return container_of(d, VirtIOS390Device, qdev);
+}
+
+/* DeviceState to VirtIOS390Device. TODO: use QOM. */
+static inline VirtIOS390Device *to_virtio_s390_device(DeviceState *d)
+{
+    return container_of(d, VirtIOS390Device, qdev);
+}
+
+static void virtio_s390_notify(DeviceState *d, uint16_t vector)
 {
-    VirtIOS390Device *dev = (VirtIOS390Device*)opaque;
+    VirtIOS390Device *dev = to_virtio_s390_device_fast(d);
     uint64_t token = s390_virtio_device_vq_token(dev, vector);
     S390CPU *cpu = s390_cpu_addr2state(0);
     CPUS390XState *env = &cpu->env;

@@ -374,9 +388,9 @@ static void virtio_s390_notify(void *opaque, uint16_t vector)
     s390_virtio_irq(env, 0, token);
 }
 
-static unsigned virtio_s390_get_features(void *opaque)
+static unsigned virtio_s390_get_features(DeviceState *d)
 {
-    VirtIOS390Device *dev = (VirtIOS390Device*)opaque;
+    VirtIOS390Device *dev = to_virtio_s390_device(d);
     return dev->host_features;
 }
hw/virtio-pci.c +39 -26

160 lines not on this page · raw message

hw/virtio.c +1 -1
index f40a8c5..fc51a4a 100644
@@ -935,7 +935,7 @@ VirtIODevice *virtio_common_init(const char *name, uint16_t device_id,
 }
 
 void virtio_bind_device(VirtIODevice *vdev, const VirtIOBindings *binding,
-                        void *opaque)
+                        DeviceState *opaque)
 {
     vdev->binding = binding;
     vdev->binding_opaque = opaque;
hw/virtio.h +13 -13
index 7c17f7b..7c40abf 100644
@@ -91,17 +91,17 @@ typedef struct VirtQueueElement
 } VirtQueueElement;
 
 typedef struct {
-    void (*notify)(void * opaque, uint16_t vector);
-    void (*save_config)(void * opaque, QEMUFile *f);
-    void (*save_queue)(void * opaque, int n, QEMUFile *f);
-    int (*load_config)(void * opaque, QEMUFile *f);
-    int (*load_queue)(void * opaque, int n, QEMUFile *f);
-    int (*load_done)(void * opaque, QEMUFile *f);
-    unsigned (*get_features)(void * opaque);
-    bool (*query_guest_notifiers)(void * opaque);
-    int (*set_guest_notifiers)(void * opaque, bool assigned);
-    int (*set_host_notifier)(void * opaque, int n, bool assigned);
-    void (*vmstate_change)(void * opaque, bool running);
+    void (*notify)(DeviceState *d, uint16_t vector);
+    void (*save_config)(DeviceState *d, QEMUFile *f);
+    void (*save_queue)(DeviceState *d, int n, QEMUFile *f);
+    int (*load_config)(DeviceState *d, QEMUFile *f);
+    int (*load_queue)(DeviceState *d, int n, QEMUFile *f);
+    int (*load_done)(DeviceState *d, QEMUFile *f);
+    unsigned (*get_features)(DeviceState *d);
+    bool (*query_guest_notifiers)(DeviceState *d);
+    int (*set_guest_notifiers)(DeviceState *d, bool assigned);
+    int (*set_host_notifier)(DeviceState *d, int n, bool assigned);
+    void (*vmstate_change)(DeviceState *d, bool running);
 } VirtIOBindings;
 
 #define VIRTIO_PCI_QUEUE_MAX 64

@@ -128,7 +128,7 @@ struct VirtIODevice
     void (*set_status)(VirtIODevice *vdev, uint8_t val);
     VirtQueue *vq;
     const VirtIOBindings *binding;
-    void *binding_opaque;
+    DeviceState *binding_opaque;
     uint16_t device_id;
     bool vm_running;
     VMChangeStateEntry *vmstate;

@@ -191,7 +191,7 @@ void virtio_update_irq(VirtIODevice *vdev);
 int virtio_set_features(VirtIODevice *vdev, uint32_t val);
 
 void virtio_bind_device(VirtIODevice *vdev, const VirtIOBindings *binding,
-                        void *opaque);
+                        DeviceState *opaque);
 
 /* Base devices.  */
 typedef struct VirtIOBlkConf VirtIOBlkConf;