RE: [PATCH] xen: Fix xen-legacy-backend qdev types

[Paul Durrant]

> -----Original Message-----
> From: Jason Andryuk <jandryuk@gmail.com>
> Sent: 24 June 2020 13:20
> To: Stefano Stabellini <sstabellini@kernel.org>; Anthony Perard 
> <anthony.perard@citrix.com>; Paul
> Durrant <paul@xen.org>; xen-devel@lists.xenproject.org
> Cc: Jason Andryuk <jandryuk@gmail.com>; qemu-devel@nongnu.org
> Subject: [PATCH] xen: Fix xen-legacy-backend qdev types
> 
> xen-sysdev is a TYPE_SYS_BUS_DEVICE.  bus_type should not be changed so
> that it can plug into the System bus.  Otherwise this assert triggers:
> qemu-system-i386: hw/core/qdev.c:102: qdev_set_parent_bus: Assertion
> `dc->bus_type && object_dynamic_cast(OBJECT(bus), dc->bus_type)'
> failed.
> 
> TYPE_XENBACKEND attaches to TYPE_XENSYSBUS, so its class_init needs to
> be set accordingly to attach the qdev.  Otherwise the following assert
> triggers:
> qemu-system-i386: hw/core/qdev.c:102: qdev_set_parent_bus: Assertion
> `dc->bus_type && object_dynamic_cast(OBJECT(bus), dc->bus_type)'
> failed.
> 
> TYPE_XENBACKEND is not a subclass of XEN_XENSYSDEV, so it's parent
> is just TYPE_DEVICE.  Change that.
> 
> Signed-off-by: Jason Andryuk <jandryuk@gmail.com>

Clearly we raced. This patch and my patch #1 are identical so I'm happy to give 
my ack to this.

  Paul

> ---
>  hw/xen/xen-legacy-backend.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/xen/xen-legacy-backend.c b/hw/xen/xen-legacy-backend.c
> index 2335ee2e65..c5c75c0064 100644
> --- a/hw/xen/xen-legacy-backend.c
> +++ b/hw/xen/xen-legacy-backend.c
> @@ -789,11 +789,12 @@ static void xendev_class_init(ObjectClass *klass, void 
> *data)
>      set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>      /* xen-backend devices can be plugged/unplugged dynamically */
>      dc->user_creatable = true;
> +    dc->bus_type = TYPE_XENSYSBUS;
>  }
> 
>  static const TypeInfo xendev_type_info = {
>      .name          = TYPE_XENBACKEND,
> -    .parent        = TYPE_XENSYSDEV,
> +    .parent        = TYPE_DEVICE,
>      .class_init    = xendev_class_init,
>      .instance_size = sizeof(struct XenLegacyDevice),
>  };
> @@ -824,7 +825,6 @@ static void xen_sysdev_class_init(ObjectClass *klass, 
> void *data)
>      DeviceClass *dc = DEVICE_CLASS(klass);
> 
>      device_class_set_props(dc, xen_sysdev_properties);
> -    dc->bus_type = TYPE_XENSYSBUS;
>  }
> 
>  static const TypeInfo xensysdev_info = {
> --
> 2.25.1