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

[Wen Congyang <wency@cn.fujitsu.com>]

At 08/19/2011 11:26 PM, Avi Kivity Write:
> On 08/18/2011 10:12 PM, Wen Congyang wrote:
>> >>
>> >>  The following patch can fix this problem, but I'm not sure whether it
>> >>  is right.
>> >
>> >  It's correct but insufficient, the filtering code (pci_bridge_filter)
>> >  needs to be updated to use the memory API.
>>
>> I read the function pci_bridge_filter(), and the function only read
>> PCI bridge's config space(command, base and limit). If base>  limit,
>> it will set addr to PCI_BAR_UNMAPPED.
>>
>> I do not find anything that needs to updated to use the memory API.
> 
> Currently it doesn't do any filtering at all.  Bridges need to create a
> new address space, then attach aliases of this region (corresponding to
> the filtered area and to the legacy vga space) to the parent bus'
> address space.

Hmm, does this problem exist before memory API is introduced?

> 
>> I add a scsi controller on pci bus1, and a scsi disk on this controller.
>> I can read and write this disk, and I do not meet any problem.
>>
> 
> However, filtering doesn't work.  You could put a BAR outside the
> filtered area and it would be visible to the guest.

How to put a BAR outside the filtered area and confirm whether it would be
virible to the guest?