[libvirt] [PATCH v2 20/24] qemu: Use PHBs to fill holes in PCI bus numbering

[Andrea Bolognani]

PCI bus has to be numbered sequentially, and no index can be
missing, so libvirt will fill in the blanks automatically for
the user.

Up until now, it has done so using either pci-bridge, for machine
types based on legacy PCI, or pcie-root-port, for machine types
based on PCI Express. Neither choice is good for pSeries guests,
where PHBs (pci-root) should be used instead.

Signed-off-by: Andrea Bolognani <abologna at redhat.com>
---
 src/qemu/qemu_domain_address.c                           | 16 +++++++++++++---
 .../qemuxml2argv-pseries-many-buses-2.args               |  2 +-
 tests/qemuxml2argvtest.c                                 |  1 -
 .../qemuxml2xmlout-pseries-many-buses-2.xml              |  7 +++----
 tests/qemuxml2xmltest.c                                  |  1 -
 5 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/qemu/qemu_domain_address.c b/src/qemu/qemu_domain_address.c
index 960ea04..082cb72 100644
--- a/src/qemu/qemu_domain_address.c
+++ b/src/qemu/qemu_domain_address.c
@@ -1097,10 +1097,14 @@ qemuDomainPCIAddressSetCreate(virDomainDefPtr def,
      * that don't yet have a corresponding controller in the domain
      * config.
      */
-    if (hasPCIeRoot)
+    if (qemuDomainIsPSeries(def)) {
+        /* pSeries guests should use PHBs (pci-root controllers) */
+        defaultModel = VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT;
+    } else if (hasPCIeRoot) {
         defaultModel = VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT_PORT;
-    else
+    } else {
         defaultModel = VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE;
+    }
 
     for (i = 1; i < addrs->nbuses; i++) {
 
@@ -2182,7 +2186,13 @@ qemuDomainAssignPCIAddresses(virDomainDefPtr def,
             dev.data.controller = def->controllers[contIndex];
             /* set connect flags so it will be properly addressed */
             qemuDomainFillDevicePCIConnectFlags(def, &dev, qemuCaps, driver);
-            if (qemuDomainPCIAddressReserveNextAddr(addrs,
+
+            /* Reserve an address for the controller. pci-root and pcie-root
+             * controllers don't plug into any other PCI controller, hence
+             * they should skip this step */
+            if (bus->model != VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT &&
+                bus->model != VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT &&
+                qemuDomainPCIAddressReserveNextAddr(addrs,
                                                     &dev.data.controller->info) < 0) {
                 goto cleanup;
             }
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-pseries-many-buses-2.args b/tests/qemuxml2argvdata/qemuxml2argv-pseries-many-buses-2.args
index 1cb5831..13fed02 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-pseries-many-buses-2.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-pseries-many-buses-2.args
@@ -19,4 +19,4 @@ server,nowait \
 -mon chardev=charmonitor,id=monitor,mode=readline \
 -boot c \
 -device spapr-pci-host-bridge,index=1,id=pci.2 \
--device pci-bridge,chassis_nr=1,id=pci.1,bus=pci.0,addr=0x1
+-device spapr-pci-host-bridge,index=2,id=pci.1
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 03290c1..34aab4a 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -1730,7 +1730,6 @@ mymain(void)
     DO_TEST("pseries-many-buses-2",
             QEMU_CAPS_CHARDEV, QEMU_CAPS_NODEFCONFIG,
             QEMU_CAPS_DEVICE_SPAPR_PCI_HOST_BRIDGE,
-            QEMU_CAPS_DEVICE_PCI_BRIDGE,
             QEMU_CAPS_VIRTIO_SCSI);
     DO_TEST("pseries-hostdevs-1",
             QEMU_CAPS_CHARDEV, QEMU_CAPS_NODEFCONFIG,
diff --git a/tests/qemuxml2xmloutdata/qemuxml2xmlout-pseries-many-buses-2.xml b/tests/qemuxml2xmloutdata/qemuxml2xmlout-pseries-many-buses-2.xml
index 75dfabf..14f3e36 100644
--- a/tests/qemuxml2xmloutdata/qemuxml2xmlout-pseries-many-buses-2.xml
+++ b/tests/qemuxml2xmloutdata/qemuxml2xmlout-pseries-many-buses-2.xml
@@ -23,10 +23,9 @@
       <target index='1'/>
     </controller>
     <controller type='usb' index='0' model='none'/>
-    <controller type='pci' index='1' model='pci-bridge'>
-      <model name='pci-bridge'/>
-      <target chassisNr='1'/>
-      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
+    <controller type='pci' index='1' model='pci-root'>
+      <model name='spapr-pci-host-bridge'/>
+      <target index='2'/>
     </controller>
     <memballoon model='none'/>
     <panic model='pseries'/>
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index a122464..ce8e60f 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -695,7 +695,6 @@ mymain(void)
     DO_TEST("pseries-many-buses-2",
             QEMU_CAPS_CHARDEV, QEMU_CAPS_NODEFCONFIG,
             QEMU_CAPS_DEVICE_SPAPR_PCI_HOST_BRIDGE,
-            QEMU_CAPS_DEVICE_PCI_BRIDGE,
             QEMU_CAPS_VIRTIO_SCSI);
     DO_TEST("pseries-hostdevs-1",
             QEMU_CAPS_CHARDEV, QEMU_CAPS_NODEFCONFIG,
-- 
2.7.5