Fixes #1 and Fixes #2 by allowing qemuargs to operate and override defaults.

builder/qemu/builder.go

@@ -17,14 +17,27 @@ import (
 const BuilderId = "transcend.qemu"
 
 var netDevice = map[string]bool{
-	"ne2k_pci": true,
-	"i82551":   true,
-	"i82557b":  true,
-	"i82559er": true,
-	"rtl8139":  true,
-	"e1000":    true,
-	"pcnet":    true,
-	"virtio":   true,
+	"ne2k_pci":   true,
+	"i82551":     true,
+	"i82557b":    true,
+	"i82559er":   true,
+	"rtl8139":    true,
+	"e1000":      true,
+	"pcnet":      true,
+	"virtio":     true,
+	"virtio-net": true,
+	"usb-net":    true,
+	"i82559a":    true,
+	"i82559b":    true,
+	"i82559c":    true,
+	"i82550":     true,
+	"i82562":     true,
+	"i82557a":    true,
+	"i82557c":    true,
+	"i82801":     true,
+	"vmxnet3":    true,
+	"i82558a":    true,
+	"i82558b":    true,
 }
 
 var diskInterface = map[string]bool{

builder/qemu/step_run.go

@@ -35,16 +35,13 @@ func cancelCallback(state multistep.StateBag) bool {
 	return cancel
 }
 
-func (s *stepRun) runVM(
-	sendBootCommands bool,
+func (s *stepRun) getCommandArgs(
 	bootDrive string,
-	state multistep.StateBag) multistep.StepAction {
+	state multistep.StateBag) []string {
 
-	config := state.Get("config").(*config)
-	driver := state.Get("driver").(Driver)
 	ui := state.Get("ui").(packer.Ui)
+	config := state.Get("config").(*config)
 	vmName := config.VMName
-
 	imgPath := filepath.Join(config.OutputDir,
 		fmt.Sprintf("%s.%s", vmName, strings.ToLower(config.Format)))
 	isoPath := state.Get("iso_path").(string)
@@ -53,7 +50,6 @@ func (s *stepRun) runVM(
 	sshHostPort := state.Get("sshHostPort").(uint)
 	vnc := fmt.Sprintf("0.0.0.0:%d", vncPort-5900)
 
-	ui.Say("Starting the virtual machine for OS Install...")
 	if config.Headless == true {
 		ui.Message("WARNING: The VM will be started in headless mode, as configured.\n" +
 			"In headless mode, errors during the boot sequence or OS setup\n" +
@@ -61,19 +57,74 @@ func (s *stepRun) runVM(
 		guiArgument = "none"
 	}
 
-	command := []string{
-		"-name", vmName,
-		"-machine", fmt.Sprintf("type=pc-1.0,accel=%s", config.Accelerator),
-		"-display", guiArgument,
-		"-net", fmt.Sprintf("nic,model=%s", config.NetDevice),
-		"-net", "user",
-		"-drive", fmt.Sprintf("file=%s,if=%s", imgPath, config.DiskInterface),
-		"-cdrom", isoPath,
-		"-boot", bootDrive,
-		"-m", "512m",
-		"-redir", fmt.Sprintf("tcp:%v::22", sshHostPort),
-		"-vnc", vnc,
+	defaultArgs := make(map[string]string)
+	defaultArgs["-name"] = vmName
+	defaultArgs["-machine"] = fmt.Sprintf("type=pc-1.0,accel=%s", config.Accelerator)
+	defaultArgs["-display"] = guiArgument
+	defaultArgs["-netdev"] = "user,id=user.0"
+	defaultArgs["-device"] = fmt.Sprintf("%s,netdev=user.0", config.NetDevice)
+	defaultArgs["-drive"] = fmt.Sprintf("file=%s,if=%s", imgPath, config.DiskInterface)
+	defaultArgs["-cdrom"] = isoPath
+	defaultArgs["-boot"] = bootDrive
+	defaultArgs["-m"] = "512m"
+	defaultArgs["-redir"] = fmt.Sprintf("tcp:%v::22", sshHostPort)
+	defaultArgs["-vnc"] = vnc
+
+	inArgs := make(map[string][]string)
+	if len(config.QemuArgs) > 0 {
+		ui.Say("Overriding defaults Qemu arguments with QemuArgs...")
+
+		// becuase qemu supports multiple appearances of the same
+		// switch, just different values, each key in the args hash
+		// will have an array of string values
+		for _, qemuArgs := range config.QemuArgs {
+			key := qemuArgs[0]
+			val := strings.Join(qemuArgs[1:], "")
+			if _, ok := inArgs[key]; !ok {
+				inArgs[key] = make([]string, 0)
+			}
+			if len(val) > 0 {
+				inArgs[key] = append(inArgs[key], val)
+			}
+		}
+	}
+
+	// get any remaining missing default args from the default settings
+	for key := range defaultArgs {
+		if _, ok := inArgs[key]; !ok {
+			arg := make([]string, 1)
+			arg[0] = defaultArgs[key]
+			inArgs[key] = arg
+		}
+	}
+
+	// Flatten to array of strings
+	outArgs := make([]string, 0)
+	for key, values := range inArgs {
+		if len(values) > 0 {
+			for idx := range values {
+				outArgs = append(outArgs, key, values[idx])
+			}
+		} else {
+			outArgs = append(outArgs, key)
+		}
 	}
+
+	return outArgs
+}
+
+func (s *stepRun) runVM(
+	sendBootCommands bool,
+	bootDrive string,
+	state multistep.StateBag) multistep.StepAction {
+
+	config := state.Get("config").(*config)
+	driver := state.Get("driver").(Driver)
+	ui := state.Get("ui").(packer.Ui)
+	vmName := config.VMName
+
+	ui.Say("Starting the virtual machine for OS Install...")
+	command := s.getCommandArgs(bootDrive, state)
 	if err := driver.Qemu(vmName, command...); err != nil {
 		err := fmt.Errorf("Error launching VM: %s", err)
 		ui.Error(err.Error())

website/source/docs/builders/qemu.html.markdown

@@ -223,7 +223,38 @@ Optional:
   values "ne2k_pci," "i82551," "i82557b," "i82559er," "rtl8139," "e1000,"
   "pcnet" or "virtio." The Qemu builder uses "virtio" by default.
 
-* `qemuargs` (array of strings reserved for future use).
+* `qemuargs` (array of array of strings) - Allows complete control over
+  the qemu command line (though not, at this time, qemu-img). Each array
+  of strings makes up a command line switch that overrides matching default
+  switch/value pairs. Any value specified as an empty string is ignored.
+  All values after the switch are concatenated with no separater. For instance:
+
+<pre class="prettyprint">
+  . . .
+  "qemuargs": [
+    [ "-m", "1024m" ],
+    [ "--no-acpi", "" ],
+    [
+       "-netdev",
+      "user,id=mynet0,",
+      "hostfwd=hostip:hostport-guestip:guestport",
+      ""
+    ],
+    [ "-device", "virtio-net,netdev=mynet0" ]
+  ]
+  . . .
+</pre>
+
+  would produce the following (not including other defaults supplied by the builder and not otherwise conflicting with the qemuargs):
+
+<pre class="prettyprint">
+    qemu-system-x86 -m 1024m --no-acpi -netdev user,id=mynet0,hostfwd=hostip:hostport-guestip:guestport -device virtio-net,netdev=mynet0"
+</pre>
+
+  Note that the qemu command line allows extreme flexibility, so beware of
+  conflicting arguments causing failures of your run. To see the defaults,
+  look in the packer.log file and search for the qemu-system-x86 command. The
+  arguments are all printed for review.
 
 * `output_directory` (string) - This is the path to the directory where the
   resulting virtual machine will be created. This may be relative or absolute.