qemu: Add disable-modern option for virtio devices

For some cases, we have to disable the fast MMIO support, by disabling
virtio 1.0. The reason for this is that we want to be able to nest our
qemu VM inside a VM run by an hypervisor with no support for fast MMIO.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

qemu.go

@@ -202,6 +202,9 @@ type FSDevice struct {
 
 	// SecurityModel is the security model for this filesystem device.
 	SecurityModel SecurityModelType
+
+	// DisableModern prevents qemu from relying on fast MMIO.
+	DisableModern bool
 }
 
 // Valid returns true if the FSDevice structure is valid and complete.
@@ -220,6 +223,9 @@ func (fsdev FSDevice) QemuParams(config *Config) []string {
 	var qemuParams []string
 
 	deviceParams = append(deviceParams, fmt.Sprintf("%s", fsdev.Driver))
+	if fsdev.DisableModern {
+		deviceParams = append(deviceParams, ",disable-modern=true")
+	}
 	deviceParams = append(deviceParams, fmt.Sprintf(",fsdev=%s", fsdev.ID))
 	deviceParams = append(deviceParams, fmt.Sprintf(",mount_tag=%s", fsdev.MountTag))
 
@@ -276,6 +282,9 @@ type CharDevice struct {
 	ID   string
 	Path string
 	Name string
+
+	// DisableModern prevents qemu from relying on fast MMIO.
+	DisableModern bool
 }
 
 // Valid returns true if the CharDevice structure is valid and complete.
@@ -294,6 +303,9 @@ func (cdev CharDevice) QemuParams(config *Config) []string {
 	var qemuParams []string
 
 	deviceParams = append(deviceParams, fmt.Sprintf("%s", cdev.Driver))
+	if cdev.DisableModern {
+		deviceParams = append(deviceParams, ",disable-modern=true")
+	}
 	if cdev.Bus != "" {
 		deviceParams = append(deviceParams, fmt.Sprintf(",bus=%s", cdev.Bus))
 	}
@@ -366,6 +378,9 @@ type NetDevice struct {
 
 	// MACAddress is the networking device interface MAC address.
 	MACAddress string
+
+	// DisableModern prevents qemu from relying on fast MMIO.
+	DisableModern bool
 }
 
 // Valid returns true if the NetDevice structure is valid and complete.
@@ -394,6 +409,9 @@ func (netdev NetDevice) QemuParams(config *Config) []string {
 		deviceParams = append(deviceParams, "driver=")
 	}
 	deviceParams = append(deviceParams, fmt.Sprintf("%s", netdev.Driver))
+	if netdev.DisableModern {
+		deviceParams = append(deviceParams, ",disable-modern=true")
+	}
 	deviceParams = append(deviceParams, fmt.Sprintf(",netdev=%s", netdev.ID))
 	deviceParams = append(deviceParams, fmt.Sprintf(",mac=%s", netdev.MACAddress))
 
@@ -454,6 +472,9 @@ type SerialDevice struct {
 
 	// ID is the serial device identifier.
 	ID string
+
+	// DisableModern prevents qemu from relying on fast MMIO.
+	DisableModern bool
 }
 
 // Valid returns true if the SerialDevice structure is valid and complete.
@@ -471,6 +492,9 @@ func (dev SerialDevice) QemuParams(config *Config) []string {
 	var qemuParams []string
 
 	deviceParams = append(deviceParams, fmt.Sprintf("%s", dev.Driver))
+	if dev.DisableModern {
+		deviceParams = append(deviceParams, ",disable-modern=true")
+	}
 	deviceParams = append(deviceParams, fmt.Sprintf(",id=%s", dev.ID))
 
 	qemuParams = append(qemuParams, "-device")
@@ -519,6 +543,9 @@ type BlockDevice struct {
 	Format    BlockDeviceFormat
 	SCSI      bool
 	WCE       bool
+
+	// DisableModern prevents qemu from relying on fast MMIO.
+	DisableModern bool
 }
 
 // Valid returns true if the BlockDevice structure is valid and complete.
@@ -537,6 +564,9 @@ func (blkdev BlockDevice) QemuParams(config *Config) []string {
 	var qemuParams []string
 
 	deviceParams = append(deviceParams, fmt.Sprintf("%s", blkdev.Driver))
+	if blkdev.DisableModern {
+		deviceParams = append(deviceParams, ",disable-modern=true")
+	}
 	deviceParams = append(deviceParams, fmt.Sprintf(",drive=%s", blkdev.ID))
 	if blkdev.SCSI == false {
 		deviceParams = append(deviceParams, ",scsi=off")

qemu_test.go

@@ -104,7 +104,7 @@ func TestAppendDeviceNVDIMM(t *testing.T) {
 	testAppend(object, deviceNVDIMMString, t)
 }
 
-var deviceFSString = "-device virtio-9p-pci,fsdev=workload9p,mount_tag=rootfs -fsdev local,id=workload9p,path=/var/lib/docker/devicemapper/mnt/e31ebda2,security_model=none"
+var deviceFSString = "-device virtio-9p-pci,disable-modern=true,fsdev=workload9p,mount_tag=rootfs -fsdev local,id=workload9p,path=/var/lib/docker/devicemapper/mnt/e31ebda2,security_model=none"
 
 func TestAppendDeviceFS(t *testing.T) {
 	fsdev := FSDevice{
@@ -114,12 +114,13 @@ func TestAppendDeviceFS(t *testing.T) {
 		Path:          "/var/lib/docker/devicemapper/mnt/e31ebda2",
 		MountTag:      "rootfs",
 		SecurityModel: None,
+		DisableModern: true,
 	}
 
 	testAppend(fsdev, deviceFSString, t)
 }
 
-var deviceNetworkString = "-device virtio-net,netdev=tap0,mac=01:02:de:ad:be:ef -netdev tap,id=tap0,ifname=ceth0,downscript=no,script=no,fds=3:4,vhost=on"
+var deviceNetworkString = "-device virtio-net,disable-modern=true,netdev=tap0,mac=01:02:de:ad:be:ef -netdev tap,id=tap0,ifname=ceth0,downscript=no,script=no,fds=3:4,vhost=on"
 
 func TestAppendDeviceNetwork(t *testing.T) {
 	foo, _ := ioutil.TempFile(os.TempDir(), "qemu-ciao-test")
@@ -138,12 +139,13 @@ func TestAppendDeviceNetwork(t *testing.T) {
 		FDs:           []*os.File{foo, bar},
 		VHost:         true,
 		MACAddress:    "01:02:de:ad:be:ef",
+		DisableModern: true,
 	}
 
 	testAppend(netdev, deviceNetworkString, t)
 }
 
-var deviceNetworkPCIString = "-device driver=virtio-net-pci,netdev=tap0,mac=01:02:de:ad:be:ef,bus=/pci-bus/pcie.0,addr=ff -netdev tap,id=tap0,ifname=ceth0,downscript=no,script=no,fds=3:4,vhost=on"
+var deviceNetworkPCIString = "-device driver=virtio-net-pci,disable-modern=true,netdev=tap0,mac=01:02:de:ad:be:ef,bus=/pci-bus/pcie.0,addr=ff -netdev tap,id=tap0,ifname=ceth0,downscript=no,script=no,fds=3:4,vhost=on"
 
 func TestAppendDeviceNetworkPCI(t *testing.T) {
 	foo, _ := ioutil.TempFile(os.TempDir(), "qemu-ciao-test")
@@ -164,17 +166,19 @@ func TestAppendDeviceNetworkPCI(t *testing.T) {
 		FDs:           []*os.File{foo, bar},
 		VHost:         true,
 		MACAddress:    "01:02:de:ad:be:ef",
+		DisableModern: true,
 	}
 
 	testAppend(netdev, deviceNetworkPCIString, t)
 }
 
-var deviceSerialString = "-device virtio-serial-pci,id=serial0"
+var deviceSerialString = "-device virtio-serial-pci,disable-modern=true,id=serial0"
 
 func TestAppendDeviceSerial(t *testing.T) {
 	sdev := SerialDevice{
 		Driver:        VirtioSerial,
 		ID:            "serial0",
+		DisableModern: true,
 	}
 
 	testAppend(sdev, deviceSerialString, t)
@@ -195,7 +199,7 @@ func TestAppendDeviceSerialPort(t *testing.T) {
 	testAppend(chardev, deviceSerialPortString, t)
 }
 
-var deviceBlockString = "-device virtio-blk,drive=hd0,scsi=off,config-wce=off -drive id=hd0,file=/var/lib/ciao.img,aio=threads,format=qcow2,if=none"
+var deviceBlockString = "-device virtio-blk,disable-modern=true,drive=hd0,scsi=off,config-wce=off -drive id=hd0,file=/var/lib/ciao.img,aio=threads,format=qcow2,if=none"
 
 func TestAppendDeviceBlock(t *testing.T) {
 	blkdev := BlockDevice{
@@ -207,6 +211,7 @@ func TestAppendDeviceBlock(t *testing.T) {
 		Interface:     NoInterface,
 		SCSI:          false,
 		WCE:           false,
+		DisableModern: true,
 	}
 
 	testAppend(blkdev, deviceBlockString, t)