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

[Isaku Yamahata <yamahata@valinux.co.jp>]

On Tue, Aug 24, 2010 at 09:43:25AM +0800, Ken CC wrote:
> 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

So parse_pci_devfn() in qdev-properties.c lacks the necessary
check. It checks fn range, but doesn't check slot range.
So please add the slot check into parse_pci_devfn(), and add assert() into
do_pci_register_device().

thanks,

> 
> 
> 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
> 
> -- 
> 

-- 
yamahata