add support for hvf accelerator to qemu builder

builder/qemu/builder.go

@@ -27,6 +27,7 @@ var accels = map[string]struct{}{
 	"tcg":  {},
 	"xen":  {},
 	"hax":  {},
+	"hvf":  {},
 }
 
 var netDevice = map[string]bool{
@@ -255,7 +256,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 
 	if _, ok := accels[b.config.Accelerator]; !ok {
 		errs = packer.MultiErrorAppend(
-			errs, errors.New("invalid accelerator, only 'kvm', 'tcg', 'xen', 'hax', or 'none' are allowed"))
+			errs, errors.New("invalid accelerator, only 'kvm', 'tcg', 'xen', 'hax', 'hvf', or 'none' are allowed"))
 	}
 
 	if _, ok := netDevice[b.config.NetDevice]; !ok {

website/source/docs/builders/qemu.html.md.erb

@@ -112,8 +112,8 @@ Linux server and have not enabled X11 forwarding (`ssh -X`).
 ### Optional:
 
 -   `accelerator` (string) - The accelerator type to use when running the VM.
-    This may be `none`, `kvm`, `tcg`, `hax`, or `xen`. The appropriate software
-    must have already been installed on your build machine to use the
+    This may be `none`, `kvm`, `tcg`, `hax`, `hvf`, or `xen`. The appropriate
+    software must have already been installed on your build machine to use the
     accelerator you specified. When no accelerator is specified, Packer will try
     to use `kvm` if it is available but will default to `tcg` otherwise.
 
@@ -121,6 +121,12 @@ Linux server and have not enabled X11 forwarding (`ssh -X`).
     upstream issue which can be tracked
     [here](https://github.com/intel/haxm/issues/20).
 
+    -> The `hvf` accelerator is new and experimental as of 
+    [QEMU 2.12.0](https://wiki.qemu.org/ChangeLog/2.12#Host_support).
+    You may encounter issues unrelated to Packer when using it.  You may need to
+    add [ "-global", "virtio-pci.disable-modern=on" ] to `qemuargs` depending on the
+    guest operating system.
+
 -   `boot_command` (array of strings) - This is an array of commands to type
     when the virtual machine is first booted. The goal of these commands should
     be to type just enough to initialize the operating system installer. Special