Re: [PATCH for-7.1] hw/mips/malta: turn off x86 specific features of PIIX4_PM

[Peter Maydell]

On Wed, 3 Aug 2022 at 18:26, Bernhard Beschow <shentey@gmail.com> wrote:
>
> On Tue, Aug 2, 2022 at 8:37 AM Philippe Mathieu-Daudé via 
> <qemu-devel@nongnu.org> wrote:
>>
>> On 28/7/22 15:16, Igor Mammedov wrote:
>> > On Thu, 28 Jul 2022 13:29:07 +0100
>> > Peter Maydell <peter.maydell@linaro.org> wrote:
>> >
>> >> On Thu, 28 Jul 2022 at 12:50, Igor Mammedov <imammedo@redhat.com> wrote:
>> >>> Disable compiled out features using compat properties as the least
>> >>> risky way to deal with issue.
>>
>> So now MIPS is forced to use meaningless compat[] to satisfy X86.
>>
>> Am I wrong seeing this as a dirty hack creeping in, yet another
>> technical debt that will hit (me...) back in a close future?
>>
>> Are we sure there are no better solution (probably more time consuming
>> and involving refactors) we could do instead?
>
>
> Working on the consolidation of piix3 and -4 soutbridges [1] I've stumbled 
> over certain design decisions where board/platform specific assumptions are 
> baked into the piix device models. I figure that's the core of the issue.
>
> In our case the ACPI functionality is implemented by inheritance while 
> perhaps it should be implemented using composition. With composition, the 
> ACPI functionality could be injected by the caller: The pc board would inject 
> it while the Malta board wouldn't. This would solve both the crash and above 
> design problem.
>
> I'd be willing to implement it but can't make any promises about the time 
> frame since I'm currently doing this in my free time. Any hints regarding the 
> implementation would be welcome, though.


For the 7.1 release (coming up real soon now) can we get consensus
on this patch from Igor as the least risky way to at least fix
the segfault ? We can look at better approaches for 7.2.

thanks
-- PMM