From 30c4bef6335fbc58432e62923d37d4617a6d9637 Mon Sep 17 00:00:00 2001
From: osy <50960678+osy@users.noreply.github.com>
Date: Fri, 25 Feb 2022 14:10:05 -0800
Subject: [PATCH] config: option to use UTC/localtime for RTC

Default to UTC unless Windows is chosen in the wizard. Existing VMs get
localtime since that was the previous default.

Fixes #3104
---
 Configuration/UTMQemuConfiguration+System.h |  1 +
 Configuration/UTMQemuConfiguration+System.m | 13 +++++++++++++
 Managers/UTMQemuSystem.m                    |  8 +++++---
 Platform/Shared/VMConfigQEMUView.swift      |  9 ++++++---
 Platform/Shared/VMWizardState.swift         |  1 +
 5 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/Configuration/UTMQemuConfiguration+System.h b/Configuration/UTMQemuConfiguration+System.h
index 0b819d56c..c457176df 100644
--- a/Configuration/UTMQemuConfiguration+System.h
+++ b/Configuration/UTMQemuConfiguration+System.h
@@ -38,6 +38,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, assign) BOOL useHypervisor;
 @property (nonatomic, readonly) BOOL isTargetArchitectureMatchHost;
 @property (nonatomic, readonly) BOOL defaultUseHypervisor;
+@property (nonatomic, assign) BOOL rtcUseLocalTime;
 
 - (void)migrateSystemConfigurationIfNecessary;
 
diff --git a/Configuration/UTMQemuConfiguration+System.m b/Configuration/UTMQemuConfiguration+System.m
index c48ae211b..2e8d04f39 100644
--- a/Configuration/UTMQemuConfiguration+System.m
+++ b/Configuration/UTMQemuConfiguration+System.m
@@ -36,6 +36,7 @@
 static const NSString *const kUTMConfigSystemUUIDKey = @"SystemUUID";
 static const NSString *const kUTMConfigMachinePropertiesKey = @"MachineProperties";
 static const NSString *const kUTMConfigUseHypervisorKey = @"UseHypervisor";
+static const NSString *const kUTMConfigRTCUseLocalTimeKey = @"RTCUseLocalTime";
 
 @interface UTMQemuConfiguration ()
 
@@ -93,6 +94,9 @@ - (void)migrateSystemConfigurationIfNecessary {
     if (self.rootDict[kUTMConfigSystemKey][kUTMConfigRngEnabledKey] == nil) {
         self.systemRngEnabled = [self.systemTarget hasPrefix:@"pc"] || [self.systemTarget hasPrefix:@"q35"] || [self.systemTarget hasPrefix:@"virt"];
     }
+    if (self.rootDict[kUTMConfigSystemKey][kUTMConfigRTCUseLocalTimeKey] == nil) {
+        self.rtcUseLocalTime = YES; // used to be default, now only for Windows
+    }
 }
 
 #pragma mark - System Properties
@@ -214,6 +218,15 @@ - (void)setUseHypervisor:(BOOL)useHypervisor {
     self.rootDict[kUTMConfigSystemKey][kUTMConfigUseHypervisorKey] = @(useHypervisor);
 }
 
+- (BOOL)rtcUseLocalTime {
+    return [self.rootDict[kUTMConfigSystemKey][kUTMConfigRTCUseLocalTimeKey] boolValue];
+}
+
+- (void)setRtcUseLocalTime:(BOOL)rtcUseLocalTime {
+    [self propertyWillChange];
+    self.rootDict[kUTMConfigSystemKey][kUTMConfigRTCUseLocalTimeKey] = @(rtcUseLocalTime);
+}
+
 #pragma mark - Additional arguments array handling
 
 - (NSInteger)countArguments {
diff --git a/Managers/UTMQemuSystem.m b/Managers/UTMQemuSystem.m
index 91803ef21..d62de6815 100644
--- a/Managers/UTMQemuSystem.m
+++ b/Managers/UTMQemuSystem.m
@@ -692,9 +692,11 @@ - (void)argsFromConfiguration {
         [self pushArgv:self.configuration.systemUUID];
     }
     
-    // fix windows time issues
-    [self pushArgv:@"-rtc"];
-    [self pushArgv:@"base=localtime"];
+    if (self.configuration.rtcUseLocalTime) {
+        // fix windows time issues
+        [self pushArgv:@"-rtc"];
+        [self pushArgv:@"base=localtime"];
+    }
 }
     
 - (void)argsFromUser {
diff --git a/Platform/Shared/VMConfigQEMUView.swift b/Platform/Shared/VMConfigQEMUView.swift
index dd9f8bedc..c5c3d0b08 100644
--- a/Platform/Shared/VMConfigQEMUView.swift
+++ b/Platform/Shared/VMConfigQEMUView.swift
@@ -39,13 +39,16 @@ struct VMConfigQEMUView: View {
     var body: some View {
         VStack {
             Form {
-                #if os(macOS)
-                Section(header: Text("Hypervisor")) {
+                Section(header: Text("Tweaks")) {
+                    #if os(macOS)
                     Toggle(isOn: $config.useHypervisor, label: {
                         Text("Use Hypervisor")
                     }).disabled(!config.isTargetArchitectureMatchHost)
+                    #endif
+                    Toggle(isOn: $config.rtcUseLocalTime, label: {
+                        Text("Use local time for base clock")
+                    }).help(Text("If checked, use local time for RTC which is required for Windows. Otherwise, use UTC clock."))
                 }
-                #endif
                 Section(header: Text("Logging")) {
                     Toggle(isOn: $config.debugLogEnabled, label: {
                         Text("Debug Logging")
diff --git a/Platform/Shared/VMWizardState.swift b/Platform/Shared/VMWizardState.swift
index 6413ea3ef..b2b57145e 100644
--- a/Platform/Shared/VMWizardState.swift
+++ b/Platform/Shared/VMWizardState.swift
@@ -402,6 +402,7 @@ enum VMWizardOS: String, Identifiable {
             }
         case .Windows:
             config.icon = "windows"
+            config.rtcUseLocalTime = true
             if let windowsBootVhdx = windowsBootVhdx {
                 config.newDrive("drive0", path: destinationFilename(forExisting: windowsBootVhdx), type: .disk, interface: mainDriveInterface)
                 generateRemovableDrive() // order matters here