Re: sysbus failed assert for xen_sysdev

[Mark Cave-Ayland <mark.cave-ayland@xxxxxxxxxxxx>]

On 22/06/2020 21:33, Jason Andryuk wrote:

> Hi,
> 
> Running qemu devel for a Xen VM is failing an assert after the recent
> "qdev: Rework how we plug into the parent bus" sysbus changes.
> 
> 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.
> 
> dc->bus_type is "xen-sysbus" and it's the
> `object_dynamic_cast(OBJECT(bus), dc->bus_type)` portion that fails
> the assert.  bus seems to be "main-system-bus", I think:
> (gdb) p *bus
> $3 = {obj = {class = 0x55555636d780, free = 0x7ffff7c40db0 <g_free>,
> properties = 0x5555563f7180, ref = 3, parent = 0x5555563fe980}, parent
> = 0x0, name = 0x5555563fec60 "main-system-bus", ...
> 
> The call comes from hw/xen/xen-legacy-backend.c:706
> sysbus_realize_and_unref(SYS_BUS_DEVICE(xen_sysdev), &error_fatal);
> 
> Any pointers on what needs to be fixed?

Hi Jason,

My understanding is that the assert() is telling you that you're plugging a
TYPE_SYS_BUS_DEVICE into a bus that isn't derived from TYPE_SYSTEM_BUS. A quick 
look
at the file in question suggests that you could try changing the parent class of
TYPE_XENSYSBUS from TYPE_BUS to TYPE_SYSTEM_BUS to see if that helps?


ATB,

Mark.