Re: [PATCH v4 5/6] i386: Hyper-V VMBus ACPI DSDT entry

[Jon Doron <arilou@gmail.com>]

On 22/05/2020, Igor Mammedow wrote:
>On Thu, 21 May 2020 18:02:07 +0200
>Paolo Bonzini <pbonzini@redhat.com> wrote:
>
>> On 13/05/20 17:34, Igor Mammedov wrote:
>> > I'd rather avoid using random IRQ numbers (considering we are
>> > dealing with black-box here). So if it's really necessary to have
>> > IRQ described here, I'd suggest to implement them in device model
>> > so they would be reserved and QEMU would error out in a sane way if
>> > IRQ conflict is detected.
>>
>> We don't generally detect ISA IRQ conflicts though, do we?
>
>that I don't know that's why I'm not suggesting how to do it.
>The point is hard-coding in AML random IRQs is not right thing to do,
>(especially with the lack of 'any' spec), as minimum AML should pull
>it from device model and that probably should be configurable and set
>by board.
>
>Other thing is:
>I haven't looked at VMBus device model in detail, but DSDT part aren't
>matching device though (device model is not ISA device hence AML part
>shouldn't be on in ISA scope), where to put it is open question.
>There were other issues with AML code, I've commented on, so I was
>waiting on respin with comments addressed.
>I don't think that this patch is good enough for merging.
>
>

But it seems like the current patch does match what's Microsoft HyperV 
is publishing in it's APCI tables.

I dont think it's correct for us to "fix" Microsoft emulation even if 
it's wrong, since that's what Windows probably expects to see...

I tried looking where Microsoft uses the ACPI tables to identify the 
VMBus but without much luck in order to understand how flexible a change 
would be for the OS to still detect the VMBus device, but in general 
I think "correcting" something that is emulated 1:1 because there is no 
spec is the right way.

>>
>> Paolo
>>
>