scsi-disk: Use qdev_prop_drive_iothread

This makes use of qdev_prop_drive_iothread for scsi-disk so that the
disk can be attached to a node that is already in the target AioContext.
We need to check that the HBA actually supports iothreads, otherwise
scsi-disk must make sure that the node is already in the main
AioContext.

This changes the error message for conflicting iothread settings.
Previously, virtio-scsi produced the error message, now it comes from
blk_set_aio_context(). Update a test case accordingly.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hw/scsi/scsi-disk.c

@@ -2336,6 +2336,13 @@ static void scsi_realize(SCSIDevice *dev, Error **errp)
         return;
     }
 
+    if (blk_get_aio_context(s->qdev.conf.blk) != qemu_get_aio_context() &&
+        !s->qdev.hba_supports_iothread)
+    {
+        error_setg(errp, "HBA does not support iothreads");
+        return;
+    }
+
     if (dev->type == TYPE_DISK) {
         if (!blkconf_geometry(&dev->conf, NULL, 65535, 255, 255, errp)) {
             return;
@@ -2929,13 +2936,14 @@ static const TypeInfo scsi_disk_base_info = {
     .abstract      = true,
 };
 
-#define DEFINE_SCSI_DISK_PROPERTIES()                                \
+#define DEFINE_SCSI_DISK_PROPERTIES()                                   \
-    DEFINE_BLOCK_PROPERTIES(SCSIDiskState, qdev.conf),               \
+    DEFINE_PROP_DRIVE_IOTHREAD("drive", SCSIDiskState, qdev.conf.blk),  \
-    DEFINE_BLOCK_ERROR_PROPERTIES(SCSIDiskState, qdev.conf),         \
+    DEFINE_BLOCK_PROPERTIES_BASE(SCSIDiskState, qdev.conf),             \
-    DEFINE_PROP_STRING("ver", SCSIDiskState, version),               \
+    DEFINE_BLOCK_ERROR_PROPERTIES(SCSIDiskState, qdev.conf),            \
-    DEFINE_PROP_STRING("serial", SCSIDiskState, serial),             \
+    DEFINE_PROP_STRING("ver", SCSIDiskState, version),                  \
-    DEFINE_PROP_STRING("vendor", SCSIDiskState, vendor),             \
+    DEFINE_PROP_STRING("serial", SCSIDiskState, serial),                \
-    DEFINE_PROP_STRING("product", SCSIDiskState, product),           \
+    DEFINE_PROP_STRING("vendor", SCSIDiskState, vendor),                \
+    DEFINE_PROP_STRING("product", SCSIDiskState, product),              \
     DEFINE_PROP_STRING("device_id", SCSIDiskState, device_id)
 
 

hw/scsi/virtio-scsi.c

@@ -789,6 +789,13 @@ static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense)
     }
 }
 
+static void virtio_scsi_pre_hotplug(HotplugHandler *hotplug_dev,
+                                    DeviceState *dev, Error **errp)
+{
+    SCSIDevice *sd = SCSI_DEVICE(dev);
+    sd->hba_supports_iothread = true;
+}
+
 static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
                                 Error **errp)
 {
@@ -798,16 +805,9 @@ static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
     int ret;
 
     if (s->ctx && !s->dataplane_fenced) {
-        AioContext *ctx;
         if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
             return;
         }
-        ctx = blk_get_aio_context(sd->conf.blk);
-        if (ctx != s->ctx && ctx != qemu_get_aio_context()) {
-            error_setg(errp, "Cannot attach a blockdev that is using "
-                       "a different iothread");
-            return;
-        }
         virtio_scsi_acquire(s);
         ret = blk_set_aio_context(sd->conf.blk, s->ctx, errp);
         virtio_scsi_release(s);
@@ -990,6 +990,7 @@ static void virtio_scsi_class_init(ObjectClass *klass, void *data)
     vdc->reset = virtio_scsi_reset;
     vdc->start_ioeventfd = virtio_scsi_dataplane_start;
     vdc->stop_ioeventfd = virtio_scsi_dataplane_stop;
+    hc->pre_plug = virtio_scsi_pre_hotplug;
     hc->plug = virtio_scsi_hotplug;
     hc->unplug = virtio_scsi_hotunplug;
 }

include/hw/scsi/scsi.h

@@ -88,6 +88,7 @@ struct SCSIDevice
     int scsi_version;
     int default_scsi_version;
     bool needs_vpd_bl_emulation;
+    bool hba_supports_iothread;
 };
 
 extern const VMStateDescription vmstate_scsi_device;

tests/qemu-iotests/240.out

@@ -43,7 +43,7 @@ QMP_VERSION
 {"return": {}}
 {"return": {}}
 {"return": {}}
-{"error": {"class": "GenericError", "desc": "Cannot attach a blockdev that is using a different iothread"}}
+{"error": {"class": "GenericError", "desc": "Cannot change iothread of active block backend"}}
 {"return": {}}
 {"return": {}}
 {"return": {}}