Raise an error if you use Qemu < 2.4 and try to use large number of adapters

gns3server/compute/qemu/qemu_vm.py

@@ -1454,7 +1454,13 @@ class QemuVM(BaseNode):
             network_options.extend(["-device", "i82801b11-bridge,id=dmi_pci_bridge{bridge_id}".format(bridge_id=bridge_id)])
             network_options.extend(["-device", "pci-bridge,id=pci-bridge{bridge_id},bus=dmi_pci_bridge{bridge_id},chassis_nr=0x1,addr=0x{bridge_id},shpc=off".format(bridge_id=bridge_id)])
 
+        if bridge_id > 1:
+            qemu_version = yield from self.manager.get_qemu_version(self.qemu_path)
+            if qemu_version and parse_version(qemu_version) < parse_version("2.4.0"):
+                raise QemuError("You need to Qemu 2.4 or later in order to support large number of adapters")
+
         pci_device_id = 4 + bridge_id  # Bridge consume PCI ports
+
         for adapter_number, adapter in enumerate(self._ethernet_adapters):
             mac = int_to_macaddress(macaddress_to_int(self._mac_address) + adapter_number)
 

tests/compute/qemu/test_qemu_vm.py

@@ -611,6 +611,9 @@ def test_build_command_large_number_of_adapters(vm, loop, fake_qemu_binary, port
     additionnal interfaces
     """
 
+    # It's supported only with Qemu 2.4 and later
+    vm.manager.get_qemu_version = AsyncioMagicMock(return_value="2.4.0")
+
     vm.adapters = 100
     vm.mac_address = "00:00:ab:0e:0f:09"
     mac_0 = vm._mac_address
@@ -626,8 +629,6 @@ def test_build_command_large_number_of_adapters(vm, loop, fake_qemu_binary, port
     assert "pci-bridge,id=pci-bridge2,bus=dmi_pci_bridge2,chassis_nr=0x1,addr=0x2,shpc=off" in cmd
     assert "i82801b11-bridge,id=dmi_pci_bridge1" in cmd
 
-    print(cmd)
-
     mac_29 = int_to_macaddress(macaddress_to_int(vm._mac_address) + 29)
     assert "e1000,mac={},bus=pci-bridge1,addr=0x04".format(mac_29) in cmd
     mac_30 = int_to_macaddress(macaddress_to_int(vm._mac_address) + 30)
@@ -635,8 +636,18 @@ def test_build_command_large_number_of_adapters(vm, loop, fake_qemu_binary, port
     mac_74 = int_to_macaddress(macaddress_to_int(vm._mac_address) + 74)
     assert "e1000,mac={},bus=pci-bridge2,addr=0x11".format(mac_74) in cmd
 
+    # Qemu < 2.4 doesn't support large number of adapters
+    vm.manager.get_qemu_version = AsyncioMagicMock(return_value="2.0.0")
+    with pytest.raises(QemuError):
+        with asyncio_patch("asyncio.create_subprocess_exec", return_value=MagicMock()) as process:
+            cmd = loop.run_until_complete(asyncio.async(vm._build_command()))
+    vm.adapters = 5
+    with asyncio_patch("asyncio.create_subprocess_exec", return_value=MagicMock()) as process:
+        cmd = loop.run_until_complete(asyncio.async(vm._build_command()))
 
 # Windows accept this kind of mistake
+
+
 @pytest.mark.skipif(sys.platform.startswith("win"), reason="Not supported on Windows")
 def test_build_command_with_invalid_options(vm, loop, fake_qemu_binary):