Re: [Qemu-devel] [PATCH 2/2] pci init: Check if devfn exceeding the max devices number supported on bus

[Ken CC <ken.ccao@gmail.com>]

On Mon, Aug 23, 2010 at 06:56:56PM +0900, Isaku Yamahata wrote:
> 
> How did you trigger the bug?
> I suppose parse_pci_devfn() in qdev-properties should check the error.
> Although I'm not objecting this patch itself, it's caller's bug.
> Just assert(devfn < PCIBUS_MAX_DEVICES)?
> 

assign pci addr > 30,

e.g.
qemu-system-x86_64 -drive \
file='./fedora.13-x86_64-virtio.qcow2',if=none,id=drv-virtio-d1,media=disk,cache=none,boot=on,format=qcow2 \
-device virtio-blk-pci,bus=pci.0,addr=0x90,drive=drv-virtio-d1,id=virtio-disk1 \
                                      ^^^^
-m 2048 -vnc :11


assert() is good to me.
and i think checking in the caller should be done too.

> On Mon, Aug 23, 2010 at 01:56:31PM +0800, Ken CC wrote:
> > 
> > Check before trying subindexing.
> > 
> > Signed-off-by: Ken CC <ken.ccao@gmail.com>
> > ---
> >  hw/pci.c |    4 ++++
> >  1 files changed, 4 insertions(+), 0 deletions(-)
> > 
> > diff --git a/hw/pci.c b/hw/pci.c
> > index a09fbac..f6f00c6 100644
> > --- a/hw/pci.c
> > +++ b/hw/pci.c
> > @@ -675,6 +675,10 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
> >          error_report("PCI: no slot/function available for %s, all in use", name);
> >          return NULL;
> >      found: ;
> > +    } else if (devfn > PCIBUS_MAX_DEVICES - 1) {
> > +        error_report("PCI: devfn is out of bus capacity."
> > +                        " Only %d devices supported.", PCIBUS_MAX_DEVICES);
> > +        return NULL;
> >      } else if (bus->devices[devfn]) {
> >          error_report("PCI: slot %d function %d not available for %s, in use by %s",
> >                       PCI_SLOT(devfn), PCI_FUNC(devfn), name, bus->devices[devfn]->name);
> > 
> > 
> > 
> 
> -- 
> yamahata

--