Re: [Qemu-devel] [PATCH] pci: fix bridge IO/BASE

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

On Sun, Mar 04, 2012 at 01:33:42PM +0000, Blue Swirl wrote:
> On Sun, Mar 4, 2012 at 13:22, Michael S. Tsirkin <mst@redhat.com> wrote:
> > On Sun, Mar 04, 2012 at 02:41:33PM +0200, Avi Kivity wrote:
> >> On 03/04/2012 02:38 PM, Blue Swirl wrote:
> >> > >>
> >> > >> This unassigned memory exception is triggered because CMD646 IDE I/O
> >> > >> registers are not accessible:
> >> > >>
> >> > >> (qemu) info pci
> >> > >>   Bus  0, device   5, function 0:
> >> > >>     IDE controller: PCI device 1095:0646
> >> > >>       IRQ 1.
> >> > >>       BAR0: I/O at 0xffffffffffffffff [0x0006].
> >> > >>       BAR1: I/O at 0xffffffffffffffff [0x0002].
> >> > >>       BAR2: I/O at 0xffffffffffffffff [0x0006].
> >> > >>       BAR3: I/O at 0xffffffffffffffff [0x0002].
> >> > >>       BAR4: I/O at 0xffffffffffffffff [0x000e].
> >> > >>       id ""
> >> > >
> >> > > The BARs are not initialized, so they aren't accessible.
> >> > >
> >> > > But perhaps the dump was not taken at the point of failure, can you
> >> > > provide a relevant dump if so?
> >> >
> >> > No, this is after failure.
> >>
> >> I don't see why the guest expects the BARs to work then.
> >
> > I don't belive it does - it probably got hang before
> > initializing BARs.
> 
> This is later, the crash happens when IDE driver is accessing CMD646
> registers after the PCI device is configured.
> 
> I changed OpenBIOS to disable any bridges with no devices, but that
> didn't help. It looks like this is not related to bridges, I disabled
> the secondary bridges with this patch and still there is the crash.

It seems to have to do with the host bridge.
It's unusual to have host bridge present itself
as a pci to pci bridge but there it is.

> diff --git a/hw/apb_pci.c b/hw/apb_pci.c
> index 1d25da8..ed9dc68 100644
> --- a/hw/apb_pci.c
> +++ b/hw/apb_pci.c
> @@ -256,11 +256,13 @@ static const MemoryRegionOps pci_ioport_ops = {
>      .endianness = DEVICE_NATIVE_ENDIAN,
>  };
> 
> +#if 0
>  /* The APB host has an IRQ line for each IRQ line of each slot.  */
>  static int pci_apb_map_irq(PCIDevice *pci_dev, int irq_num)
>  {
>      return ((pci_dev->devfn & 0x18) >> 1) + irq_num;
>  }
> +#endif
> 
>  static int pci_pbm_map_irq(PCIDevice *pci_dev, int irq_num)
>  {
> @@ -322,8 +324,10 @@ PCIBus *pci_apb_init(target_phys_addr_t special_base,
>      SysBusDevice *s;
>      APBState *d;
>      unsigned int i;
> +#if 0
>      PCIDevice *pci_dev;
>      PCIBridge *br;
> +#endif
> 
>      /* Ultrasparc PBM main bus */
>      dev = qdev_create(NULL, "pbm");
> @@ -352,6 +356,7 @@ PCIBus *pci_apb_init(target_phys_addr_t special_base,
> 
>      pci_create_simple(d->bus, 0, "pbm-pci");
> 
> +#if 0
>      /* APB secondary busses */
>      pci_dev = pci_create_multifunction(d->bus, PCI_DEVFN(1, 0), true,
>                                     "pbm-bridge");
> @@ -368,7 +373,7 @@ PCIBus *pci_apb_init(target_phys_addr_t special_base,
>                         pci_apb_map_irq);
>      qdev_init_nofail(&pci_dev->qdev);
>      *bus3 = pci_bridge_get_sec_bus(br);
> -
> +#endif
>      return d->bus;
>  }
> 
> >
> >> --
> >> error compiling committee.c: too many arguments to function