Re: [RFC PATCH 9/9] hw/xen: Have legacy Xen backend inherit from DYNAMIC_SYS_BUS_DEVICE

[Bernhard Beschow]

Am 25. Januar 2025 18:13:43 UTC schrieb "Philippe Mathieu-Daudé" 
<philmd@linaro.org>:
>Because the legacy Xen backend devices can optionally be plugged on the
>TYPE_PLATFORM_BUS_DEVICE, have it inherit TYPE_DYNAMIC_SYS_BUS_DEVICE.
>Remove the implicit TYPE_XENSYSDEV instance_size.
>
>Untested, but I'm surprised the legacy devices work because they
>had a broken instance size (QDev instead of Sysbus...), so accesses
>of XenLegacyDevice fields were overwritting sysbus ones.
>
>Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>---
> include/hw/xen/xen_pvdev.h  | 3 ++-
> hw/xen/xen-legacy-backend.c | 7 ++-----
> 2 files changed, 4 insertions(+), 6 deletions(-)
>
>diff --git a/include/hw/xen/xen_pvdev.h b/include/hw/xen/xen_pvdev.h
>index 0c984440476..48950dc2b57 100644
>--- a/include/hw/xen/xen_pvdev.h
>+++ b/include/hw/xen/xen_pvdev.h
>@@ -32,7 +32,8 @@ struct XenDevOps {
> };
> 
> struct XenLegacyDevice {
>-    DeviceState        qdev;
>+    SysBusDevice parent_obj;

This then needs sysbus.h rather than qdev-core.h include.

Moreover, the patch in the reply needs to be inserted into the series before 
this patch.

Both are needed for the patch to compile.

Best regards,
Bernhard

>+
>     const char         *type;
>     int                dom;
>     int                dev;
>diff --git a/hw/xen/xen-legacy-backend.c b/hw/xen/xen-legacy-backend.c
>index 118c571b3a7..4d079e35d83 100644
>--- a/hw/xen/xen-legacy-backend.c
>+++ b/hw/xen/xen-legacy-backend.c
>@@ -640,16 +640,14 @@ static void xendev_class_init(ObjectClass *klass, void 
>*data)
>     DeviceClass *dc = DEVICE_CLASS(klass);
> 
>     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_DEVICE,
>+    .parent        = TYPE_DYNAMIC_SYS_BUS_DEVICE,
>     .class_init    = xendev_class_init,
>-    .instance_size = sizeof(struct XenLegacyDevice),
>+    .instance_size = sizeof(XenLegacyDevice),
> };
> 
> static void xen_sysbus_class_init(ObjectClass *klass, void *data)
>@@ -672,7 +670,6 @@ static const TypeInfo xensysbus_info = {
> static const TypeInfo xensysdev_info = {
>     .name          = TYPE_XENSYSDEV,
>     .parent        = TYPE_SYS_BUS_DEVICE,
>-    .instance_size = sizeof(SysBusDevice),
> };
> 
> static void xenbe_register_types(void)