qemu: support virt-2.6 machine type on arm

Some places already check for "virt-" prefix as well as plain "virt".
virQEMUCapsHasPCIMultiBus did not, resulting in multiple PCI devices
having assigned the same unnumbered "pci" alias.

Add a test for the "virt-2.6" machine type which also omits the
<model type='virtio'/> in <interface>, to check if
qemuDomainDefaultNetModel works too.

https://bugzilla.redhat.com/show_bug.cgi?id=1325085
(cherry picked from commit f06ca25d)

src/qemu/qemu_capabilities.c

@@ -2172,7 +2172,8 @@ bool virQEMUCapsHasPCIMultiBus(virQEMUCapsPtr qemuCaps,
         /* If 'virt' supports PCI, it supports multibus.
          * No extra conditions here for simplicity.
          */
-        if (STREQ(def->os.machine, "virt"))
+        if (STREQ(def->os.machine, "virt") ||
+            STRPREFIX(def->os.machine, "virt-"))
             return true;
     }
 

src/qemu/qemu_domain.c

@@ -1479,7 +1479,8 @@ qemuDomainDefaultNetModel(const virDomainDef *def,
         if (STREQ(def->os.machine, "versatilepb"))
             return "smc91c111";
 
-        if (STREQ(def->os.machine, "virt"))
+        if (STREQ(def->os.machine, "virt") ||
+            STRPREFIX(def->os.machine, "virt-"))
             return "virtio";
 
         /* Incomplete. vexpress (and a few others) use this, but not all

tests/qemuxml2argvdata/qemuxml2argv-aarch64-virt-2.6-virtio-pci-default.args

+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-aarch64 \
+-name aarch64test \
+-S \
+-M virt-2.6 \
+-cpu cortex-a53 \
+-m 1024 \
+-smp 1 \
+-uuid 496d7ea8-9739-544b-4ebd-ef08be936e8b \
+-nographic \
+-nodefconfig \
+-nodefaults \
+-monitor unix:/tmp/lib/domain--1-aarch64test/monitor.sock,server,nowait \
+-boot c \
+-kernel /aarch64.kernel \
+-initrd /aarch64.initrd \
+-append 'earlyprintk console=ttyAMA0,115200n8 rw root=/dev/vda rootwait' \
+-dtb /aarch64.dtb \
+-device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1 \
+-device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x1 \
+-device virtio-serial-device,id=virtio-serial0 \
+-usb \
+-drive file=/aarch64.raw,format=raw,if=none,id=drive-virtio-disk0 \
+-device virtio-blk-device,drive=drive-virtio-disk0,id=virtio-disk0 \
+-device virtio-net-device,vlan=0,id=net0,mac=52:54:00:09:a4:37 \
+-net user,vlan=0,name=hostnet0 \
+-serial pty \
+-chardev pty,id=charconsole1 \
+-device virtconsole,chardev=charconsole1,id=console1 \
+-device virtio-balloon-device,id=balloon0 \
+-object rng-random,id=objrng0,filename=/dev/random \
+-device virtio-rng-device,rng=objrng0,id=rng0

tests/qemuxml2argvdata/qemuxml2argv-aarch64-virt-2.6-virtio-pci-default.xml

+<domain type="qemu">
+  <name>aarch64test</name>
+  <uuid>496d7ea8-9739-544b-4ebd-ef08be936e8b</uuid>
+  <memory>1048576</memory>
+  <currentMemory>1048576</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch="aarch64" machine="virt-2.6">hvm</type>
+    <kernel>/aarch64.kernel</kernel>
+    <initrd>/aarch64.initrd</initrd>
+    <dtb>/aarch64.dtb</dtb>
+    <cmdline>earlyprintk console=ttyAMA0,115200n8 rw root=/dev/vda rootwait</cmdline>
+  </os>
+  <features>
+    <acpi/>
+    <apic/>
+    <pae/>
+  </features>
+  <cpu match='exact'>
+    <model>cortex-a53</model>
+  </cpu>
+  <clock offset="utc"/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>restart</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-aarch64</emulator>
+    <disk type='file' device='disk'>
+      <source file='/aarch64.raw'/>
+      <target dev='vda' bus='virtio'/>
+    </disk>
+    <interface type='user'>
+      <mac address='52:54:00:09:a4:37'/>
+    </interface>
+    <console type='pty'/>
+    <console type='pty'>
+      <target type='virtio' port='0'/>
+    </console>
+    <memballoon model='virtio'/>
+    <!--
+      This actually doesn't work in practice because vexpress only has
+      4 virtio slots available, rng makes 5 -->
+    <rng model='virtio'>
+      <backend model='random'>/dev/random</backend>
+    </rng>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -1661,6 +1661,12 @@ mymain(void)
             QEMU_CAPS_DEVICE_VIRTIO_RNG, QEMU_CAPS_OBJECT_RNG_RANDOM,
             QEMU_CAPS_OBJECT_GPEX, QEMU_CAPS_DEVICE_PCI_BRIDGE,
             QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE);
+    DO_TEST("aarch64-virt-2.6-virtio-pci-default",
+            QEMU_CAPS_NODEFCONFIG, QEMU_CAPS_DTB,
+            QEMU_CAPS_DEVICE_VIRTIO_MMIO,
+            QEMU_CAPS_DEVICE_VIRTIO_RNG, QEMU_CAPS_OBJECT_RNG_RANDOM,
+            QEMU_CAPS_OBJECT_GPEX, QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE);
     /* Example of using virtio-pci with no explicit PCI controller
        but with manual PCI addresses */
     DO_TEST("aarch64-virtio-pci-manual-addresses",