Re: [Qemu-devel] [PATCH] pci: add standard bridge device

[Avi Kivity <avi@redhat.com>]

On 09/04/2011 05:54 PM, Michael S. Tsirkin wrote:
> >  Way too late.  And also won't work, since often the offset is
> >  determined by one party and the size by another.
>
> For things like BARs, yes - but these don't need to be
> that big normally. We could add an additinal API
> that gets first/last parameters. last<  first means 0 size.
> Feasible?

Let's defer this for now.

Does PCI actually have 64-bit addresses?  Note that most/all cpus don't.

We may need 65-bit arithmetic for that.

>
> >  >VGA I/O addresses (including ISA aliases address - AD[15::10] are not
> >  >decoded):
> >  >AD[9::0] = 3B0h through 3BBh and 3C0h through 3DFh
> >
> >  These "not decoded" bits mean you need to instantiate tons of
> >  aliases to implement correctly.
> >  I plan to add core support for that eventually.
>
> There's a flag to enable 16-bit decode actually:
> bit 4 in bridge control register.
> How does VGA work at the moment without a bridge? Ignores the ISA aliases?
> then we can do that too I think.
>

Of course it doesn't ignore it.  See the 440fx implementation, if you 
disable VGA access (via the SMRAM register), vga goes away.

(vga registers its legacy space as a subregion of pci_address_space(dev))

-- 
error compiling committee.c: too many arguments to function