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

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Sep 09, 2011 at 03:24:54PM +0800, Wen Congyang wrote:
> At 09/09/2011 03:12 PM, Michael S. Tsirkin Write:
> > On Fri, Sep 09, 2011 at 02:43:24PM +0800, Wen Congyang wrote:
> >>> However, filtering doesn't work.  You could put a BAR outside the
> >>> filtered area and it would be visible to the guest.
> >>>
> >>
> >> I test it on real hardware. If I put a BAR outside the filterer area, and
> >> then run 'lspci -vv', the BAR does not change:
> > 
> > ...
> > 
> > 
> >> The BAR1 is feafbc00, and it is in the bus2's range.
> >> I map the BAR(mmap /sys/bus/pci/devices/0000\:03\:01.0/resource1), and find
> >> I can read and write the memory.
> >>
> >> Thanks
> >> Wen Congyang
> > 
> > So, it's as expected. Nothing seems wrong with this picture. But
> > this is not the test that Avi suggested.
> 
> Sorry for my misunderstand.
> My question is: How to put a BAR outside the filterer area,

Write into address/limit registers on the bridge to make them
not cover the BAR behind.

> and how to know
> whether it is visible?
> 
> Thanks
> Wen Congyang

Read the BAR memory as you did.

-- 
MST