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
The original, initial "/pci" fragment has been replaced with
"/pci-root@4", which (a) looks better, (b) provides all the necessary
information.
Cc: Markus Armbruster <arm...@redhat.com>
Cc: Marcel Apfelbaum <mar...@redhat.com>
Cc: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Laszlo Ersek <ler...@redhat.com>
---
Notes:
v3:
- using new sysbus device property, not inserting additional bus
hw/pci-bridge/pci_expander_bridge.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/hw/pci-bridge/pci_expander_bridge.c
b/hw/pci-bridge/pci_expander_bridge.c
index c7a085d..d468670 100644
--- a/hw/pci-bridge/pci_expander_bridge.c
+++ b/hw/pci-bridge/pci_expander_bridge.c
@@ -93,7 +93,7 @@ static void pxb_host_class_init(ObjectClass *class, void
*data)
DeviceClass *dc = DEVICE_CLASS(class);
PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(class);
- dc->fw_name = "pci";
+ dc->fw_name = "pci-root";
hc->root_bus_path = pxb_host_root_bus_path;
}
@@ -152,6 +152,7 @@ static int pxb_dev_initfn(PCIDevice *dev)
{
PXBDev *pxb = PXB_DEV(dev);
DeviceState *ds, *bds;
+ char *bus_nr_str;
PCIBus *bus;
const char *dev_name = NULL;
@@ -166,6 +167,10 @@ static int pxb_dev_initfn(PCIDevice *dev)
}
ds = qdev_create(NULL, TYPE_PXB_HOST);
+ bus_nr_str = g_strdup_printf("%x", pxb->bus_nr);
+ qdev_prop_set_string(ds, "explicit_ofw_unit_address", bus_nr_str);
+ g_free(bus_nr_str);
+
bus = pci_bus_new(ds, "pxb-internal", NULL, NULL, 0, TYPE_PXB_BUS);
bus->parent_dev = dev;
--
1.8.3.1
