Re: [Qemu-devel] [PATCH v3 6/6] hw/pci-bridge: set explicit OFW unit address for TYPE_PXB_HOST

[Marcel Apfelbaum <marcel@redhat.com>]

On 06/11/2015 01:45 PM, Laszlo Ersek wrote:
> On 06/11/15 12:29, Marcel Apfelbaum wrote:
>> On 06/11/2015 01:26 PM, Laszlo Ersek wrote:
>>> On 06/11/15 12:21, Marcel Apfelbaum wrote:
>>>> On 06/11/2015 03:38 AM, Laszlo Ersek wrote:
>>>>> The PXB implementation doesn't allow firmware (SeaBIOS or OVMF) to boot
>>>>> off devices behind the PXB. This happens because the
>>>>> sysbus_get_fw_dev_path() function in "hw/core/sysbus.c" doesn't have
>>>>> enough information to format a unique identifier for the PXB in
>>>>> question,
>>>>> and consequently the OpenFirmware device path passed down to the guest
>>>>> firmware in the "bootorder" fw_cfg file is unusable for identifying the
>>>>> boot device.
>>>>>
>>>>> For example, the command line fragment
>>>>>
>>>>>      -device pxb,id=bridge1,bus_nr=4 \
>>>>>      \
>>>>>      -netdev user,id=netdev0 \
>>>>>      -device e1000,netdev=netdev0,bus=bridge1,addr=2,bootindex=0
>>>>>
>>>>> results in the following "bootorder" entry:
>>>>>
>>>>>      /pci/pci-bridge@0/ethernet@2/ethernet-phy@0
>>>>>
>>>>> The initial "pci" node is formatted by sysbus_get_fw_dev_path(), and
>>>>> the
>>>>> resultant OpenFirmware device path is independent of bus_nr=4 -- and
>>>>> therefore it is useless for identifying the device.
>>>>>
>>>>> In this patch we change the fw_name device class member of
>>>>> TYPE_PXB_HOST
>>>>> from "pci" to "pci-root", and set each instance's explicit OFW unit
>>>>> address to the PXB bus number. The same command line fragment
>>>>> results in
>>>>> the following OpenFirmware device path in the "bootorder" fw_cfg file:
>>>>>
>>>>>      /pci-root@4/pci-bridge@0/ethernet@2/ethernet-phy@0
>>>> Hi Laszlo,
>>>>
>>>> I applied your patches but I still get
>>>> /pci@i0cf8/ethernet@5/ethernet-phy@0
>>>> in the boot list
>>>>
>>>> I checked and  the code enters only once in sysbus_get_fw_dev_path
>>>> for pci@i0cf8 and goes for pio branch.
>>>>
>>>> Do you know maybe what I missed?
>>>
>>> I think so, yes: you added the ...,bootorder=N property to a device that
>>> is *not* behind a PXB. :) You forgot the ...,bus=bridgeX property.
>>
>> Actually:
>> -device pxb,id=bridge1,bus_nr=4 -netdev user,id=u \
>> -device
>> e1000,id=net2,bus=bridge1,netdev=u,addr=0x5,bootindex=0,romfile=../pc-bios/efi-e1000.rom,bus=pci.0
>>
>>
>> Hmm :(
>
> Count the "bus=" substrings on your command line :)
Wow! Why would I do that to myself? I need a coffee fast!

>
> Laszlo
>