Re: [Qemu-devel] [Xen-devel] [PATCH][XSA-126] xen: limit guest control of PCI command register

[Michael S. Tsirkin]

On Wed, Jun 10, 2015 at 08:00:55AM +0100, Jan Beulich wrote:
> >>> On 08.06.15 at 13:28, <address@hidden> wrote:
> > On Mon, Jun 08, 2015 at 11:55:22AM +0100, Jan Beulich wrote:
> >> while function 0 has
> >> 
> >> 0x10: Base Address Register 0  = 0xca23000c (Memory space, 64-bit access, 
> >> prefetchable)
> >> 0x18: Base Address Register 2  = 0xca24000c (Memory space, 64-bit access, 
> >> prefetchable)
> >> 0x20: Base Address Register 4  = 0xca25000c (Memory space, 64-bit access, 
> >> prefetchable)
> >> 
> >> and function 1
> >> 
> >> 0x10: Base Address Register 0  = 0xca20000c (Memory space, 64-bit access, 
> >> prefetchable)
> >> 0x18: Base Address Register 2  = 0xca21000c (Memory space, 64-bit access, 
> >> prefetchable)
> >> 0x20: Base Address Register 4  = 0xca22000c (Memory space, 64-bit access, 
> >> prefetchable)
> >> 
> >> > Does the sibling device have a BAR overlapping the address?
> >> 
> >> No, its BARs are fully separate.
> > 
> > Judging from the above, it's actually function 1's BAR 2 that
> > is accessed? Are you saying disabling memory on function 0
> > breaks function 2 somehow?
> 
> Oops, just noticed I didn't reply to this. Not sure how you
> come to that conclusion - the ITP log says that the bad write is to
> 0xca25004c.
> 
> 
> Jan

Look at the bridge configuration though - looks like it
will only forward transactions to 0xca21XXXX.
Anything else will be terminated by the bridge itself.

-- 
MST