Re: [PATCH for-6.0 0/4] Don't treat all sysbus devices as hotpluggable

[Richard Henderson <richard.henderson@linaro.org>]

On 3/25/21 9:33 AM, Peter Maydell wrote:
> On the two machines which have the "platform bus" (ppc e500 and arm
> virt) we currently treat all TYPE_SYS_BUS_DEVICE devices as being
> hotpluggable in the device callbacks, and try to plug those devices
> into the platform bus.  This is far too broad, because only a handful
> of devices are actually valid to plug into the platform bus.
> Moreover, if a device which is pluggable for some other reason (like
> a PCI device) happens to use a sysbus device internally as part of
> its implementation, the hotplug callback will incorrectly grab that
> sysbus device, probably resulting in an assertion failure.
> 
> Mostly PCI devices don't use sysbus devices internally, so the only
> case we've encountered so far is the not-valid-anyway
>   qemu-system-ppc64 -M ppce500 -device macio-oldworld
> but we might create more in future.
> 
> This series restricts hotpluggability of sysbus devices on these
> platforms to those devices which are on the dynamic sysbus whitelist

s/whitelist/allowlist/g ?

>    include/hw/boards.h: Document machine_class_allow_dynamic_sysbus_dev()
>    machine: Provide a function to check the dynamic sysbus whitelist
>    hw/arm/virt: Only try to add valid dynamic sysbus devices to platform
>      bus
>    hw/ppc/e500plat: Only try to add valid dynamic sysbus devices to
>      platform bus

Otherwise,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~