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

[Michael S. Tsirkin]

On Sun, Sep 04, 2011 at 03:40:58PM +0300, Avi Kivity wrote:
> 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 )

What about BAR directly behind pci0?
That should be unaffected by bridges pci1 and pci2
since the device is not behind that.


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