[Qemu-devel] [PATCH] spapr-pci: change the default PCI bus naming

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Previously libvirt required the first/default PCI bus to have name "pci".
Since QEMU can support multiple buses now, libvirt wants "pci.0" now.

This removes custom busname and lets QEMU make up default names.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---

I tested this with:
  -netdev tap,id=id0,ifname=tapqemu-tap-00,script=ifup.sh,downscript=ifdown.sh \
  -device e1000,id=id1,netdev=id0,mac=C0:41:49:4b:00:00 \
  -device \
  spapr-pci-host-bridge,index=5,id=aikbus \
  -netdev tap,id=id2,ifname=tap-1,script=ifup.sh,downscript=ifdown.sh \
  -device rtl8139,id=id3,netdev=id2,bus=aikbus.0,mac=C0:41:49:4b:00:01 \
  -device spapr-pci-vfio-host-bridge,id=id4,index=10,iommu=4 \

This creates a default PCI, an additional emulated PCI bus (named aikbus,
if I omit the name, it is pci.1 which is also fine) and VFIO bus (which is
not in upstream yet but still), this all works fine and I cannot see any flaw.


---
 hw/ppc/spapr_pci.c | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 66ddf10..7ecb3df 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -499,7 +499,6 @@ static int spapr_phb_init(SysBusDevice *s)
     DeviceState *dev = DEVICE(s);
     sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(s);
     PCIHostState *phb = PCI_HOST_BRIDGE(s);
-    const char *busname;
     char *namebuf;
     int i;
     PCIBus *bus;
@@ -583,26 +582,8 @@ static int spapr_phb_init(SysBusDevice *s)
                              get_system_io(), 0, SPAPR_PCI_IO_WIN_SIZE);
     memory_region_add_subregion(get_system_memory(), sphb->io_win_addr,
                                 &sphb->iowindow);
-    /*
-     * Selecting a busname is more complex than you'd think, due to
-     * interacting constraints.  If the user has specified an id
-     * explicitly for the phb , then we want to use the qdev default
-     * of naming the bus based on the bridge device (so the user can
-     * then assign devices to it in the way they expect).  For the
-     * first / default PCI bus (index=0) we want to use just "pci"
-     * because libvirt expects there to be a bus called, simply,
-     * "pci".  Otherwise, we use the same name as in the device tree,
-     * since it's unique by construction, and makes the guest visible
-     * BUID clear.
-     */
-    if (dev->id) {
-        busname = NULL;
-    } else if (sphb->index == 0) {
-        busname = "pci";
-    } else {
-        busname = sphb->dtbusname;
-    }
-    bus = pci_register_bus(dev, busname,
+
+    bus = pci_register_bus(dev, NULL,
                            pci_spapr_set_irq, pci_spapr_map_irq, sphb,
                            &sphb->memspace, &sphb->iospace,
                            PCI_DEVFN(0, 0), PCI_NUM_PINS, TYPE_PCI_BUS);
-- 
1.8.4.rc4