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

[Avi Kivity <avi@redhat.com>]

On 09/04/2011 03:30 PM, Michael S. Tsirkin wrote:
> >
> >  Create a memory region for the bridge's address space.  This region
> >  is not directly added to system_memory or its descendants.
>
> I do this for each bridge in the hierarchy, right?

Each bridge does this independently (so yes).

> >  fx440 does exactly this, with the following cosmetic changes:
> >
> >  - the windows are different (vga, pci hole, 64-bit pci area, PAMx, SMRAM)
> >  - instead of mapping them to the parent bridge's
> >  pci_address_space(), we map them to get_system_memory()
>
> Hmm, what ties the windows of a child bridge
> to be within the windows of a parent?
>

system_memory
   |
   +--- pci0_alias0 (aliases part of pci0)

pci0
   |
   +--- pci1_alias0 (a bridge)

pci1
   |
   +--- pci2_alias0 (another bridge)

pci2
   |
   +--- BAR

When rendering the memory hierarchy, the only parts of BAR which are 
visible are those that fit the clipping regions pci0_alias0 ^ 
pci1_alias0 ^ pci2_alias0.  If there are multiple aliases (like the low 
and high PCI holes, and PAM, it becomes (pci0_alias0 v pci0_alias1) ^ 
(pci1_alias0v pci1_alias1) ^ (pci2_alias0 v pci2_alias1). ( "^" == 
intersection, "v" == union )

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