Since commit 1d2d974244 "spapr_pci: enumerate and add PCI device tree", QEMU
populates the PCI device tree in the opposite order compared to SLOF.
Before 1d2d974244:
Populating /pci@800000020000000
00 0000 (D) : 1af4 1000 virtio [ net ]
00 0800 (D) : 1af4 1001 virtio [ block ]
00 1000 (D) : 1af4 1009 virtio [ network ]
Populating /pci@800000020000000/unknown-legacy-device@2
7e5294b8 : /pci@800000020000000
7e52b998 : |-- ethernet@0
7e52c0c8 : |-- scsi@1
7e52c7e8 : +-- unknown-legacy-device@2 ok
Since 1d2d974244:
Populating /pci@800000020000000
00 1000 (D) : 1af4 1009 virtio [ network ]
Populating /pci@800000020000000/unknown-legacy-device@2
00 0800 (D) : 1af4 1001 virtio [ block ]
00 0000 (D) : 1af4 1000 virtio [ net ]
7e5e8118 : /pci@800000020000000
7e5ea6a0 : |-- unknown-legacy-device@2
7e5eadb8 : |-- scsi@1
7e5eb4d8 : +-- ethernet@0 ok
This behaviour change is not actually a bug since no assumptions should be
made on DT ordering. But it has no real justification either, other than
being the consequence of the way fdt_add_subnode() inserts new elements
to the front of the FDT rather than adding them to the tail.
This patch reverts to the historical SLOF ordering by walking PCI devices
in reverse order. This reconciles pseries with x86 machine types behavior.
It is expected to make things easier when porting existing applications to
power.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
(slight update to the changelog)
Signed-off-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
a8eeafda19