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


From: Marcel Apfelbaum
Subject: Re: [Qemu-devel] [PATCH v3 6/6] hw/pci-bridge: set explicit OFW unit address for TYPE_PXB_HOST
Date: Thu, 11 Jun 2015 13:55:01 +0300
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0

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/address@hidden/address@hidden/address@hidden

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:

     /address@hidden/address@hidden/address@hidden/address@hidden
Hi Laszlo,

I applied your patches but I still get
/address@hidden/address@hidden/address@hidden
in the boot list

I checked and  the code enters only once in sysbus_get_fw_dev_path
for address@hidden 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





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