It is currently not possible to perform a strict boot from USB storage:
$ qemu-system-ppc64 -accel kvm -nodefaults -nographic -serial stdio \
-boot strict=on \
-device qemu-xhci \
-device usb-storage,drive=disk,bootindex=0 \
-blockdev driver=file,node-name=disk,filename=fedora-ppc64le.qcow2
SLOF **********************************************************************
QEMU Starting
Build Date = Jul 17 2020 11:15:24
FW Version = git-e18ddad8516ff2cf
Press "s" to enter Open Firmware.
Populating /vdevice methods
Populating /vdevice/vty@71000000
Populating /vdevice/nvram@71000001
Populating /pci@800000020000000
00 0000 (D) : 1b36 000d serial bus [ usb-xhci ]
No NVRAM common partition, re-initializing...
Scanning USB
XHCI: Initializing
USB Storage
SCSI: Looking for devices
101000000000000 DISK : "QEMU QEMU HARDDISK 2.5+"
Using default console: /vdevice/vty@71000000
Welcome to Open Firmware
Copyright (c) 2004, 2017 IBM Corporation All rights reserved.
This program and the accompanying materials are made available
under the terms of the BSD License available at
http://www.opensource.org/licenses/bsd-license.php
Trying to load: from: /pci@800000020000000/usb@0/storage@1/disk@101000000000000 ...
E3405: No such device
E3407: Load failed
Type 'boot' and press return to continue booting the system.
Type 'reset-all' and press return to reboot the system.
Ready!
0 >
The device tree handed over by QEMU to SLOF indeed contains:
qemu,boot-list =
"/pci@800000020000000/usb@0/storage@1/disk@101000000000000 HALT";
but the device node is named usb-xhci@0, not usb@0.
This happens because the firmware names of PCI devices returned
by get_boot_devices_list() come from pcibus_get_fw_dev_path(),
while the sPAPR PHB code uses a different naming scheme for
device nodes. This inconsistency has always been there but it was
hidden for a long time because SLOF used to rename USB device
nodes, until this commit, merged in QEMU 4.2.0 :
commit 85164ad4ed
Author: Alexey Kardashevskiy <aik@ozlabs.ru>
Date: Wed Sep 11 16:24:32 2019 +1000
pseries: Update SLOF firmware image
This fixes USB host bus adapter name in the device tree to match QEMU's
one.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Fortunately, sPAPR implements the firmware path provider interface.
This provides a way to override the default firmware paths.
Just factor out the sPAPR PHB naming logic from spapr_dt_pci_device()
to a helper, and use it in the sPAPR firmware path provider hook.
Fixes: 85164ad4ed ("pseries: Update SLOF firmware image")
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210122170157.246374-1-groug@kaod.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
040bdafce1