Add global config for FML mode custom resolution

Add a new global config value app.fml.resolution to set custom resolution
for FML apps. This is a string value in the format of "widthxheight".

Signed-off-by: Shahriyar Jalayeri <[email protected]>

docs/CONFIG-PROPERTIES.md

@@ -3,6 +3,7 @@
 | Name | Type | Default | Description |
 | ---- | ---- | ------- | ----------- |
 | app.allow.vnc | boolean | false (only local access) | allow access to EVE's VNC ports from external IPs |
+| app.fml.resolution | string | notset | Set system-wide value of forced resolution for applications running in FML mode, it can be one of [predefined](/pkg/pillar/types/global.go) FmlResolution* values. |
 | timer.config.interval | integer in seconds | 60 | how frequently device gets config |
 | timer.cert.interval | integer in seconds | 1 day (24*3600) | how frequently device checks for new controller certificates |
 | timer.metric.interval  | integer in seconds | 60 | how frequently device reports metrics |

pkg/pillar/hypervisor/kvm.go

@@ -780,6 +780,17 @@ func isVncShimVMEnabled(
 	return config.EnableVnc && (config.EnableVncShimVM || globalShimVnc)
 }
 
+func getFmlCustomResolution(globalConfig *types.ConfigItemValueMap) (string, error) {
+	if globalConfig != nil {
+		item, ok := globalConfig.GlobalSettings[types.FmlCustomResolution]
+		if ok {
+			return item.StringValue(), nil
+		}
+	}
+
+	return "", fmt.Errorf("no custom resolution found")
+}
+
 // CreateDomConfig creates a domain config (a qemu config file,
 // typically named something like xen-%d.cfg)
 func (ctx KvmContext) CreateDomConfig(domainName string,
@@ -796,6 +807,24 @@ func (ctx KvmContext) CreateDomConfig(domainName string,
 		isVncShimVMEnabled(globalConfig, config)
 	tmplCtx.DomainConfig.DisplayName = domainName
 
+	fmlResolutions, err := getFmlCustomResolution(globalConfig)
+	if err != nil {
+		// this should never happen, but just in case
+		logError("failed to get fml-mode custom resolution, reverting back to notset. error : %v", err)
+		fmlResolutions = types.FmlResolutionNotSet
+	}
+
+	if fmlResolutions != types.FmlResolutionNotSet {
+		// logError for visibility
+		logError("Setting FML resolution to : %s", fmlResolutions)
+		if fmlResolutions == types.FmlResolution1024x768 {
+			// do what ever else needed, like set the custom ovmf vars
+		}
+		if fmlResolutions == types.FmlResolution1920x1080 {
+			// do what ever else needed, like set the custom ovmf vars
+		}
+	}
+
 	// render global device model settings
 	t, _ := template.New("qemu").Parse(qemuConfTemplate)
 	if err := t.Execute(file, tmplCtx); err != nil {

pkg/pillar/types/global.go

@@ -264,6 +264,8 @@ const (
 	SyslogLogLevel GlobalSettingKey = "debug.syslog.loglevel"
 	// KernelLogLevel global setting key
 	KernelLogLevel GlobalSettingKey = "debug.kernel.loglevel"
+	// FmlCustomResolution global setting key
+	FmlCustomResolution GlobalSettingKey = "app.fml.resolution"
 
 	// XXX Temporary flag to disable RFC 3442 classless static route usage
 	DisableDHCPAllOnesNetMask GlobalSettingKey = "debug.disable.dhcp.all-ones.netmask"
@@ -358,6 +360,15 @@ var (
 	SyslogKernelDefaultLogLevel = "info"
 )
 
+var (
+	// FmlResolutionNotSet is a string to indicate that custom resolution is not set
+	FmlResolutionNotSet = "notset"
+	// FmlResolution1024x768 is a string to indicate 1024x768 resolution
+	FmlResolution1024x768 = "1024x768"
+	// FmlResolution1920x1080 is a string to indicate 1280x720 resolution
+	FmlResolution1920x1080 = "1920x1080"
+)
+
 // ConfigItemSpec - Defines what a specification for a configuration should be
 type ConfigItemSpec struct {
 	Key      string
@@ -911,6 +922,7 @@ func NewConfigItemSpecMap() ConfigItemSpecMap {
 	configItemSpecMap.AddStringItem(DefaultRemoteLogLevel, "info", validateLogrusLevel)
 	configItemSpecMap.AddStringItem(SyslogLogLevel, "info", validateSyslogKernelLevel)
 	configItemSpecMap.AddStringItem(KernelLogLevel, "info", validateSyslogKernelLevel)
+	configItemSpecMap.AddStringItem(FmlCustomResolution, FmlResolutionNotSet, validateCustomResolution)
 
 	// Add Agent Settings
 	configItemSpecMap.AddAgentSettingStringItem(LogLevel, "info", validateLogrusLevel)
@@ -943,6 +955,15 @@ func validateSyslogKernelLevel(level string) error {
 	return nil
 }
 
+func validateCustomResolution(res string) error {
+	// it can be notset or one of the predefined resolutions
+	if res == FmlResolutionNotSet || res == FmlResolution1024x768 || res == FmlResolution1920x1080 {
+		return nil
+	}
+
+	return fmt.Errorf("validateCustomResolution: invalid resolution '%v'", res)
+}
+
 // blankValidator - A validator that accepts any string
 func blankValidator(s string) error {
 	return nil

pkg/pillar/types/global_test.go

@@ -200,6 +200,7 @@ func TestNewConfigItemSpecMap(t *testing.T) {
 		DefaultRemoteLogLevel,
 		SyslogLogLevel,
 		KernelLogLevel,
+		FmlCustomResolution,
 		DisableDHCPAllOnesNetMask,
 		ProcessCloudInitMultiPart,
 		NetDumpEnable,