Re: [PATCH kvm-unit-tests 2/4] Introduce a C++ wrapper for the kvm APIs

[Anthony Liguori <anthony@codemonkey.ws>]

On 11/24/2010 10:48 AM, Gleb Natapov wrote:
>> They *aren't* ISA devices.  Look at the PIIX3 spec.  All of the
>> ports for these devices are positively decoded and not sent over the
>> ISA bus.
>>
>>      
> Over the external ISA bus you mean?
>    

There is no internal ISA bus.  The reality is that the PIIX3 is a 
microcontroller and most of the platform devices are probably written in 
microcode.  That's certainly the case with modern SuperIO chips.

Very specifically, the PIIX3 has a white list of addresses that when it 
sees the a PCI bus transaction for those addresses, it asserts DEVSEL# 
and then routes the request to the write part of the chip to handle it.  
For unhandled transactions, it then forwards them to the ISA bus.

Regards,

Anthony Liguori