Re: [Qemu-devel] [PATCH] pci: Error on PCI capability collisions

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

On Wed, Aug 24, 2011 at 12:10:32PM +0200, Jan Kiszka wrote:
> On 2011-08-24 12:04, Michael S. Tsirkin wrote:
> > On Tue, Aug 23, 2011 at 07:28:08PM +0200, Jan Kiszka wrote:
> >> From: Alex Williamson <alex.williamson@redhat.com>
> >>
> >> Nothing good can happen when we overlap capabilities
> >>
> >> [ Jan: rebased over qemu, minor formatting ]
> >>
> >> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> > 
> > This doesn't build for me:
> > 
> > /scm/qemu/hw/pci.c: In function ‘pci_add_capability’:
> > /scm/qemu/hw/pci.c:1970:45: error: ‘PCIDevice’ has no member named ‘config_map’
> 
> Yeah, sorry, forgot to refresh the commit before posting.

Happens to me too, sometimes.

> > 
> > I think that what that includes is the capability including each given
> > offset, right?  It would be easy to write some code scanning the
> > capability list to figure this value out.
> > Something along the lines of (untested):
> > 
> > static
> > uint8_t pci_find_capability_at_offset(PCIDevice *pdev, uint8_t offset)
> > {                                       
> >     uint8_t next, prev, found = 0;
> > 
> >     if (!(pdev->config[PCI_STATUS] & PCI_STATUS_CAP_LIST))
> >         return 0;
> > 
> >     for (prev = PCI_CAPABILITY_LIST; (next = pdev->config[prev]);
> >          prev = next + PCI_CAP_LIST_NEXT)
> >         if (next <= offset && next > found)
> >             found = next;
> > 
> >     return found;
> > }
> 
> Sounds useful, will enhance the patch.
> 
> (Originally, I just wanted to reduce the qemu-kvm delta... :) )
> 
> Jan

Oh, if you want to just drop that bit, that's also fine.
Up to you.

-- 
MST