31 files changed, 370 insertions, 193 deletions

diff --git a/src/common/uuid.cpp b/src/common/uuid.cpp
index d7435a6e9..2b6a530e3 100644
--- a/src/common/uuid.cpp
+++ b/src/common/uuid.cpp
@@ -1,23 +1,25 @@
-// Copyright 2018 yuzu Emulator Project
+// Copyright 2022 yuzu Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <bit>
+#include <optional>
 #include <random>
 
 #include <fmt/format.h>
 
 #include "common/assert.h"
+#include "common/tiny_mt.h"
 #include "common/uuid.h"
 
 namespace Common {
 
 namespace {
 
-bool IsHexDigit(char c) {
-    return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
-}
+constexpr size_t RawStringSize = sizeof(UUID) * 2;
+constexpr size_t FormattedStringSize = RawStringSize + 4;
 
-u8 HexCharToByte(char c) {
+std::optional<u8> HexCharToByte(char c) {
     if (c >= '0' && c <= '9') {
         return static_cast<u8>(c - '0');
     }
@@ -28,60 +30,184 @@ u8 HexCharToByte(char c) {
         return static_cast<u8>(c - 'A' + 10);
     }
     ASSERT_MSG(false, "{} is not a hexadecimal digit!", c);
-    return u8{0};
+    return std::nullopt;
 }
 
-} // Anonymous namespace
+std::array<u8, 0x10> ConstructFromRawString(std::string_view raw_string) {
+    std::array<u8, 0x10> uuid;
+
+    for (size_t i = 0; i < RawStringSize; i += 2) {
+        const auto upper = HexCharToByte(raw_string[i]);
+        const auto lower = HexCharToByte(raw_string[i + 1]);
+        if (!upper || !lower) {
+            return {};
+        }
+        uuid[i / 2] = static_cast<u8>((*upper << 4) | *lower);
+    }
+
+    return uuid;
+}
 
-u128 HexStringToU128(std::string_view hex_string) {
-    const size_t length = hex_string.length();
+std::array<u8, 0x10> ConstructFromFormattedString(std::string_view formatted_string) {
+    std::array<u8, 0x10> uuid;
 
-    // Detect "0x" prefix.
-    const bool has_0x_prefix = length > 2 && hex_string[0] == '0' && hex_string[1] == 'x';
-    const size_t offset = has_0x_prefix ? 2 : 0;
+    size_t i = 0;
 
-    // Check length.
-    if (length > 32 + offset) {
-        ASSERT_MSG(false, "hex_string has more than 32 hexadecimal characters!");
-        return INVALID_UUID;
+    // Process the first 8 characters.
+    const auto* str = formatted_string.data();
+
+    for (; i < 4; ++i) {
+        const auto upper = HexCharToByte(*(str++));
+        const auto lower = HexCharToByte(*(str++));
+        if (!upper || !lower) {
+            return {};
+        }
+        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
+    }
+
+    // Process the next 4 characters.
+    ++str;
+
+    for (; i < 6; ++i) {
+        const auto upper = HexCharToByte(*(str++));
+        const auto lower = HexCharToByte(*(str++));
+        if (!upper || !lower) {
+            return {};
+        }
+        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
     }
 
-    u64 lo = 0;
-    u64 hi = 0;
-    for (size_t i = 0; i < length - offset; ++i) {
-        const char c = hex_string[length - 1 - i];
-        if (!IsHexDigit(c)) {
-            ASSERT_MSG(false, "{} is not a hexadecimal digit!", c);
-            return INVALID_UUID;
+    // Process the next 4 characters.
+    ++str;
+
+    for (; i < 8; ++i) {
+        const auto upper = HexCharToByte(*(str++));
+        const auto lower = HexCharToByte(*(str++));
+        if (!upper || !lower) {
+            return {};
         }
-        if (i < 16) {
-            lo |= u64{HexCharToByte(c)} << (i * 4);
+        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
+    }
+
+    // Process the next 4 characters.
+    ++str;
+
+    for (; i < 10; ++i) {
+        const auto upper = HexCharToByte(*(str++));
+        const auto lower = HexCharToByte(*(str++));
+        if (!upper || !lower) {
+            return {};
         }
-        if (i >= 16) {
-            hi |= u64{HexCharToByte(c)} << ((i - 16) * 4);
+        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
+    }
+
+    // Process the last 12 characters.
+    ++str;
+
+    for (; i < 16; ++i) {
+        const auto upper = HexCharToByte(*(str++));
+        const auto lower = HexCharToByte(*(str++));
+        if (!upper || !lower) {
+            return {};
         }
+        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
+    }
+
+    return uuid;
+}
+
+std::array<u8, 0x10> ConstructUUID(std::string_view uuid_string) {
+    const auto length = uuid_string.length();
+
+    if (length == 0) {
+        return {};
+    }
+
+    // Check if the input string contains 32 hexadecimal characters.
+    if (length == RawStringSize) {
+        return ConstructFromRawString(uuid_string);
+    }
+
+    // Check if the input string has the length of a RFC 4122 formatted UUID string.
+    if (length == FormattedStringSize) {
+        return ConstructFromFormattedString(uuid_string);
     }
-    return u128{lo, hi};
+
+    ASSERT_MSG(false, "UUID string has an invalid length of {} characters!", length);
+
+    return {};
+}
+
+} // Anonymous namespace
+
+UUID::UUID(std::string_view uuid_string) : uuid{ConstructUUID(uuid_string)} {}
+
+std::string UUID::RawString() const {
+    return fmt::format("{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}"
+                       "{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}",
+                       uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5], uuid[6], uuid[7],
+                       uuid[8], uuid[9], uuid[10], uuid[11], uuid[12], uuid[13], uuid[14],
+                       uuid[15]);
+}
+
+std::string UUID::FormattedString() const {
+    return fmt::format("{:02x}{:02x}{:02x}{:02x}"
+                       "-{:02x}{:02x}-{:02x}{:02x}-{:02x}{:02x}-"
+                       "{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}",
+                       uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5], uuid[6], uuid[7],
+                       uuid[8], uuid[9], uuid[10], uuid[11], uuid[12], uuid[13], uuid[14],
+                       uuid[15]);
+}
+
+size_t UUID::Hash() const noexcept {
+    u64 upper_hash;
+    u64 lower_hash;
+
+    std::memcpy(&upper_hash, uuid.data(), sizeof(u64));
+    std::memcpy(&lower_hash, uuid.data() + sizeof(u64), sizeof(u64));
+
+    return upper_hash ^ std::rotl(lower_hash, 1);
 }
 
-UUID UUID::Generate() {
+u128 UUID::AsU128() const {
+    u128 uuid_old;
+    std::memcpy(&uuid_old, uuid.data(), sizeof(UUID));
+    return uuid_old;
+}
+
+UUID UUID::MakeRandom() {
     std::random_device device;
-    std::mt19937 gen(device());
-    std::uniform_int_distribution<u64> distribution(1, std::numeric_limits<u64>::max());
-    return UUID{distribution(gen), distribution(gen)};
+
+    return MakeRandomWithSeed(device());
 }
 
-std::string UUID::Format() const {
-    return fmt::format("{:016x}{:016x}", uuid[1], uuid[0]);
+UUID UUID::MakeRandomWithSeed(u32 seed) {
+    // Create and initialize our RNG.
+    TinyMT rng;
+    rng.Initialize(seed);
+
+    UUID uuid;
+
+    // Populate the UUID with random bytes.
+    rng.GenerateRandomBytes(uuid.uuid.data(), sizeof(UUID));
+
+    return uuid;
 }
 
-std::string UUID::FormatSwitch() const {
-    std::array<u8, 16> s{};
-    std::memcpy(s.data(), uuid.data(), sizeof(u128));
-    return fmt::format("{:02x}{:02x}{:02x}{:02x}-{:02x}{:02x}-{:02x}{:02x}-{:02x}{:02x}-{:02x}{"
-                       ":02x}{:02x}{:02x}{:02x}{:02x}",
-                       s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7], s[8], s[9], s[10], s[11],
-                       s[12], s[13], s[14], s[15]);
+UUID UUID::MakeRandomRFC4122V4() {
+    auto uuid = MakeRandom();
+
+    // According to Proposed Standard RFC 4122 Section 4.4, we must:
+
+    // 1. Set the two most significant bits (bits 6 and 7) of the
+    //    clock_seq_hi_and_reserved to zero and one, respectively.
+    uuid.uuid[8] = 0x80 | (uuid.uuid[8] & 0x3F);
+
+    // 2. Set the four most significant bits (bits 12 through 15) of the
+    //    time_hi_and_version field to the 4-bit version number from Section 4.1.3.
+    uuid.uuid[6] = 0x40 | (uuid.uuid[6] & 0xF);
+
+    return uuid;
 }
 
 } // namespace Common
diff --git a/src/common/uuid.h b/src/common/uuid.h
index 8ea01f8da..fe31e64e6 100644
--- a/src/common/uuid.h
+++ b/src/common/uuid.h
@@ -1,9 +1,11 @@
-// Copyright 2018 yuzu Emulator Project
+// Copyright 2022 yuzu Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
 #pragma once
 
+#include <array>
+#include <functional>
 #include <string>
 #include <string_view>
 
@@ -11,69 +13,119 @@
 
 namespace Common {
 
-constexpr u128 INVALID_UUID{{0, 0}};
-
-/**
- * Converts a hex string to a 128-bit unsigned integer.
- *
- * The hex string can be formatted in lowercase or uppercase, with or without the "0x" prefix.
- *
- * This function will assert and return INVALID_UUID under the following conditions:
- * - If the hex string is more than 32 characters long
- * - If the hex string contains non-hexadecimal characters
- *
- * @param hex_string Hexadecimal string
- *
- * @returns A 128-bit unsigned integer if successfully converted, INVALID_UUID otherwise.
- */
-[[nodiscard]] u128 HexStringToU128(std::string_view hex_string);
-
 struct UUID {
-    // UUIDs which are 0 are considered invalid!
-    u128 uuid;
-    UUID() = default;
-    constexpr explicit UUID(const u128& id) : uuid{id} {}
-    constexpr explicit UUID(const u64 lo, const u64 hi) : uuid{{lo, hi}} {}
-    explicit UUID(std::string_view hex_string) {
-        uuid = HexStringToU128(hex_string);
-    }
-
-    [[nodiscard]] constexpr explicit operator bool() const {
-        return uuid != INVALID_UUID;
-    }
-
-    [[nodiscard]] constexpr bool operator==(const UUID& rhs) const {
-        return uuid == rhs.uuid;
-    }
-
-    [[nodiscard]] constexpr bool operator!=(const UUID& rhs) const {
-        return !operator==(rhs);
-    }
-
-    // TODO(ogniK): Properly generate uuids based on RFC-4122
-    [[nodiscard]] static UUID Generate();
-
-    // Set the UUID to {0,0} to be considered an invalid user
-    constexpr void Invalidate() {
-        uuid = INVALID_UUID;
+    std::array<u8, 0x10> uuid{};
+
+    /// Constructs an invalid UUID.
+    constexpr UUID() = default;
+
+    /// Constructs a UUID from a reference to a 128 bit array.
+    constexpr explicit UUID(const std::array<u8, 16>& uuid_) : uuid{uuid_} {}
+
+    /**
+     * Constructs a UUID from either:
+     * 1. A 32 hexadecimal character string representing the bytes of the UUID
+     * 2. A RFC 4122 formatted UUID string, in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+     *
+     * The input string may contain uppercase or lowercase characters, but they must:
+     * 1. Contain valid hexadecimal characters (0-9, a-f, A-F)
+     * 2. Not contain the "0x" hexadecimal prefix
+     *
+     * Should the input string not meet the above requirements,
+     * an assert will be triggered and an invalid UUID is set instead.
+     */
+    explicit UUID(std::string_view uuid_string);
+
+    ~UUID() = default;
+
+    constexpr UUID(const UUID&) noexcept = default;
+    constexpr UUID(UUID&&) noexcept = default;
+
+    constexpr UUID& operator=(const UUID&) noexcept = default;
+    constexpr UUID& operator=(UUID&&) noexcept = default;
+
+    /**
+     * Returns whether the stored UUID is valid or not.
+     *
+     * @returns True if the stored UUID is valid, false otherwise.
+     */
+    constexpr bool IsValid() const {
+        return uuid != std::array<u8, 0x10>{};
     }
 
-    [[nodiscard]] constexpr bool IsInvalid() const {
-        return uuid == INVALID_UUID;
-    }
-    [[nodiscard]] constexpr bool IsValid() const {
-        return !IsInvalid();
+    /**
+     * Returns whether the stored UUID is invalid or not.
+     *
+     * @returns True if the stored UUID is invalid, false otherwise.
+     */
+    constexpr bool IsInvalid() const {
+        return !IsValid();
     }
 
-    // TODO(ogniK): Properly generate a Nintendo ID
-    [[nodiscard]] constexpr u64 GetNintendoID() const {
-        return uuid[0];
+    /**
+     * Returns a 32 hexadecimal character string representing the bytes of the UUID.
+     *
+     * @returns A 32 hexadecimal character string of the UUID.
+     */
+    std::string RawString() const;
+
+    /**
+     * Returns a RFC 4122 formatted UUID string in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
+     *
+     * @returns A RFC 4122 formatted UUID string.
+     */
+    std::string FormattedString() const;
+
+    /**
+     * Returns a 64-bit hash of the UUID for use in hash table data structures.
+     *
+     * @returns A 64-bit hash of the UUID.
+     */
+    size_t Hash() const noexcept;
+
+    /// DO NOT USE. Copies the contents of the UUID into a u128.
+    u128 AsU128() const;
+
+    /**
+     * Creates a default UUID "yuzu Default UID".
+     *
+     * @returns A UUID with its bytes set to the ASCII values of "yuzu Default UID".
+     */
+    static constexpr UUID MakeDefault() {
+        return UUID{
+            {'y', 'u', 'z', 'u', ' ', 'D', 'e', 'f', 'a', 'u', 'l', 't', ' ', 'U', 'I', 'D'},
+        };
     }
 
-    [[nodiscard]] std::string Format() const;
-    [[nodiscard]] std::string FormatSwitch() const;
+    /**
+     * Creates a random UUID.
+     *
+     * @returns A random UUID.
+     */
+    static UUID MakeRandom();
+
+    /**
+     * Creates a random UUID with a seed.
+     *
+     * @param seed A seed to initialize the Mersenne-Twister RNG
+     *
+     * @returns A random UUID.
+     */
+    static UUID MakeRandomWithSeed(u32 seed);
+
+    /**
+     * Creates a random UUID. The generated UUID is RFC 4122 Version 4 compliant.
+     *
+     * @returns A random UUID that is RFC 4122 Version 4 compliant.
+     */
+    static UUID MakeRandomRFC4122V4();
+
+    friend constexpr bool operator==(const UUID& lhs, const UUID& rhs) = default;
 };
-static_assert(sizeof(UUID) == 16, "UUID is an invalid size!");
+static_assert(sizeof(UUID) == 0x10, "UUID has incorrect size.");
+
+/// An invalid UUID. This UUID has all its bytes set to 0.
+constexpr UUID InvalidUUID = {};
 
 } // namespace Common
 
@@ -82,7 +134,7 @@ namespace std {
 template <>
 struct hash<Common::UUID> {
     size_t operator()(const Common::UUID& uuid) const noexcept {
-        return uuid.uuid[1] ^ uuid.uuid[0];
+        return uuid.Hash();
     }
 };
 
diff --git a/src/core/frontend/applets/profile_select.cpp b/src/core/frontend/applets/profile_select.cpp
index 3e4f90be2..4c58c310f 100644
--- a/src/core/frontend/applets/profile_select.cpp
+++ b/src/core/frontend/applets/profile_select.cpp
@@ -13,8 +13,7 @@ ProfileSelectApplet::~ProfileSelectApplet() = default;
 void DefaultProfileSelectApplet::SelectProfile(
     std::function<void(std::optional<Common::UUID>)> callback) const {
     Service::Account::ProfileManager manager;
-    callback(manager.GetUser(Settings::values.current_user.GetValue())
-                 .value_or(Common::UUID{Common::INVALID_UUID}));
+    callback(manager.GetUser(Settings::values.current_user.GetValue()).value_or(Common::UUID{}));
     LOG_INFO(Service_ACC, "called, selecting current user instead of prompting...");
 }
 
diff --git a/src/core/hid/emulated_controller.cpp b/src/core/hid/emulated_controller.cpp
index a7cdf45e6..2bee173b3 100644
--- a/src/core/hid/emulated_controller.cpp
+++ b/src/core/hid/emulated_controller.cpp
@@ -269,7 +269,8 @@ void EmulatedController::ReloadInput() {
     }
 
     // Use a common UUID for TAS
-    const auto tas_uuid = Common::UUID{0x0, 0x7A5};
+    static constexpr Common::UUID TAS_UUID = Common::UUID{
+        {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x7, 0xA5, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}};
 
     // Register TAS devices. No need to force update
     for (std::size_t index = 0; index < tas_button_devices.size(); ++index) {
@@ -278,8 +279,8 @@ void EmulatedController::ReloadInput() {
         }
         tas_button_devices[index]->SetCallback({
             .on_change =
-                [this, index, tas_uuid](const Common::Input::CallbackStatus& callback) {
-                    SetButton(callback, index, tas_uuid);
+                [this, index](const Common::Input::CallbackStatus& callback) {
+                    SetButton(callback, index, TAS_UUID);
                 },
         });
     }
@@ -290,8 +291,8 @@ void EmulatedController::ReloadInput() {
         }
         tas_stick_devices[index]->SetCallback({
             .on_change =
-                [this, index, tas_uuid](const Common::Input::CallbackStatus& callback) {
-                    SetStick(callback, index, tas_uuid);
+                [this, index](const Common::Input::CallbackStatus& callback) {
+                    SetStick(callback, index, TAS_UUID);
                 },
         });
     }
diff --git a/src/core/hle/ipc_helpers.h b/src/core/hle/ipc_helpers.h
index cf204f570..026257115 100644
--- a/src/core/hle/ipc_helpers.h
+++ b/src/core/hle/ipc_helpers.h
@@ -404,6 +404,11 @@ inline s32 RequestParser::Pop() {
     return static_cast<s32>(Pop<u32>());
 }
 
+// Ignore the -Wclass-memaccess warning on memcpy for non-trivially default constructible objects.
+#if defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wclass-memaccess"
+#endif
 template <typename T>
 void RequestParser::PopRaw(T& value) {
     static_assert(std::is_trivially_copyable_v<T>,
@@ -411,6 +416,9 @@ void RequestParser::PopRaw(T& value) {
     std::memcpy(&value, cmdbuf + index, sizeof(T));
     index += (sizeof(T) + 3) / 4; // round up to word length
 }
+#if defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
 
 template <typename T>
 T RequestParser::PopRaw() {
diff --git a/src/core/hle/service/acc/acc.cpp b/src/core/hle/service/acc/acc.cpp
index 6e63e057e..e34ef5a78 100644
--- a/src/core/hle/service/acc/acc.cpp
+++ b/src/core/hle/service/acc/acc.cpp
@@ -39,9 +39,9 @@ constexpr ResultCode ERR_FAILED_SAVE_DATA{ErrorModule::Account, 100};
 // Thumbnails are hard coded to be at least this size
 constexpr std::size_t THUMBNAIL_SIZE = 0x24000;
 
-static std::filesystem::path GetImagePath(Common::UUID uuid) {
+static std::filesystem::path GetImagePath(const Common::UUID& uuid) {
     return Common::FS::GetYuzuPath(Common::FS::YuzuPath::NANDDir) /
-           fmt::format("system/save/8000000000000010/su/avators/{}.jpg", uuid.FormatSwitch());
+           fmt::format("system/save/8000000000000010/su/avators/{}.jpg", uuid.FormattedString());
 }
 
 static constexpr u32 SanitizeJPEGSize(std::size_t size) {
@@ -290,7 +290,7 @@ public:
 
 protected:
     void Get(Kernel::HLERequestContext& ctx) {
-        LOG_DEBUG(Service_ACC, "called user_id=0x{}", user_id.Format());
+        LOG_DEBUG(Service_ACC, "called user_id=0x{}", user_id.RawString());
         ProfileBase profile_base{};
         ProfileData data{};
         if (profile_manager.GetProfileBaseAndData(user_id, profile_base, data)) {
@@ -300,21 +300,21 @@ protected:
             rb.PushRaw(profile_base);
         } else {
             LOG_ERROR(Service_ACC, "Failed to get profile base and data for user=0x{}",
-                      user_id.Format());
+                      user_id.RawString());
             IPC::ResponseBuilder rb{ctx, 2};
             rb.Push(ResultUnknown); // TODO(ogniK): Get actual error code
         }
     }
 
     void GetBase(Kernel::HLERequestContext& ctx) {
-        LOG_DEBUG(Service_ACC, "called user_id=0x{}", user_id.Format());
+        LOG_DEBUG(Service_ACC, "called user_id=0x{}", user_id.RawString());
         ProfileBase profile_base{};
         if (profile_manager.GetProfileBase(user_id, profile_base)) {
             IPC::ResponseBuilder rb{ctx, 16};
             rb.Push(ResultSuccess);
             rb.PushRaw(profile_base);
         } else {
-            LOG_ERROR(Service_ACC, "Failed to get profile base for user=0x{}", user_id.Format());
+            LOG_ERROR(Service_ACC, "Failed to get profile base for user=0x{}", user_id.RawString());
             IPC::ResponseBuilder rb{ctx, 2};
             rb.Push(ResultUnknown); // TODO(ogniK): Get actual error code
         }
@@ -373,7 +373,7 @@ protected:
         LOG_DEBUG(Service_ACC, "called, username='{}', timestamp={:016X}, uuid=0x{}",
                   Common::StringFromFixedZeroTerminatedBuffer(
                       reinterpret_cast<const char*>(base.username.data()), base.username.size()),
-                  base.timestamp, base.user_uuid.Format());
+                  base.timestamp, base.user_uuid.RawString());
 
         if (user_data.size() < sizeof(ProfileData)) {
             LOG_ERROR(Service_ACC, "ProfileData buffer too small!");
@@ -406,7 +406,7 @@ protected:
         LOG_DEBUG(Service_ACC, "called, username='{}', timestamp={:016X}, uuid=0x{}",
                   Common::StringFromFixedZeroTerminatedBuffer(
                       reinterpret_cast<const char*>(base.username.data()), base.username.size()),
-                  base.timestamp, base.user_uuid.Format());
+                  base.timestamp, base.user_uuid.RawString());
 
         if (user_data.size() < sizeof(ProfileData)) {
             LOG_ERROR(Service_ACC, "ProfileData buffer too small!");
@@ -435,7 +435,7 @@ protected:
     }
 
     ProfileManager& profile_manager;
-    Common::UUID user_id{Common::INVALID_UUID}; ///< The user id this profile refers to.
+    Common::UUID user_id{}; ///< The user id this profile refers to.
 };
 
 class IProfile final : public IProfileCommon {
@@ -547,7 +547,7 @@ private:
 
         IPC::ResponseBuilder rb{ctx, 4};
         rb.Push(ResultSuccess);
-        rb.PushRaw<u64>(user_id.GetNintendoID());
+        rb.PushRaw<u64>(user_id.Hash());
     }
 
     void EnsureIdTokenCacheAsync(Kernel::HLERequestContext& ctx) {
@@ -577,7 +577,7 @@ private:
 
         IPC::ResponseBuilder rb{ctx, 4};
         rb.Push(ResultSuccess);
-        rb.PushRaw<u64>(user_id.GetNintendoID());
+        rb.PushRaw<u64>(user_id.Hash());
     }
 
     void StoreOpenContext(Kernel::HLERequestContext& ctx) {
@@ -587,7 +587,7 @@ private:
     }
 
     std::shared_ptr<EnsureTokenIdCacheAsyncInterface> ensure_token_id{};
-    Common::UUID user_id{Common::INVALID_UUID};
+    Common::UUID user_id{};
 };
 
 // 6.0.0+
@@ -687,7 +687,7 @@ void Module::Interface::GetUserCount(Kernel::HLERequestContext& ctx) {
 void Module::Interface::GetUserExistence(Kernel::HLERequestContext& ctx) {
     IPC::RequestParser rp{ctx};
     Common::UUID user_id = rp.PopRaw<Common::UUID>();
-    LOG_DEBUG(Service_ACC, "called user_id=0x{}", user_id.Format());
+    LOG_DEBUG(Service_ACC, "called user_id=0x{}", user_id.RawString());
 
     IPC::ResponseBuilder rb{ctx, 3};
     rb.Push(ResultSuccess);
@@ -718,7 +718,7 @@ void Module::Interface::GetLastOpenedUser(Kernel::HLERequestContext& ctx) {
 void Module::Interface::GetProfile(Kernel::HLERequestContext& ctx) {
     IPC::RequestParser rp{ctx};
     Common::UUID user_id = rp.PopRaw<Common::UUID>();
-    LOG_DEBUG(Service_ACC, "called user_id=0x{}", user_id.Format());
+    LOG_DEBUG(Service_ACC, "called user_id=0x{}", user_id.RawString());
 
     IPC::ResponseBuilder rb{ctx, 2, 0, 1};
     rb.Push(ResultSuccess);
@@ -833,7 +833,7 @@ void Module::Interface::GetProfileEditor(Kernel::HLERequestContext& ctx) {
     IPC::RequestParser rp{ctx};
     Common::UUID user_id = rp.PopRaw<Common::UUID>();
 
-    LOG_DEBUG(Service_ACC, "called, user_id=0x{}", user_id.Format());
+    LOG_DEBUG(Service_ACC, "called, user_id=0x{}", user_id.RawString());
 
     IPC::ResponseBuilder rb{ctx, 2, 0, 1};
     rb.Push(ResultSuccess);
@@ -875,7 +875,7 @@ void Module::Interface::StoreSaveDataThumbnailApplication(Kernel::HLERequestCont
     IPC::RequestParser rp{ctx};
     const auto uuid = rp.PopRaw<Common::UUID>();
 
-    LOG_WARNING(Service_ACC, "(STUBBED) called, uuid=0x{}", uuid.Format());
+    LOG_WARNING(Service_ACC, "(STUBBED) called, uuid=0x{}", uuid.RawString());
 
     // TODO(ogniK): Check if application ID is zero on acc initialize. As we don't have a reliable
     // way of confirming things like the TID, we're going to assume a non zero value for the time
@@ -889,7 +889,7 @@ void Module::Interface::StoreSaveDataThumbnailSystem(Kernel::HLERequestContext&
     const auto uuid = rp.PopRaw<Common::UUID>();
     const auto tid = rp.Pop<u64_le>();
 
-    LOG_WARNING(Service_ACC, "(STUBBED) called, uuid=0x{}, tid={:016X}", uuid.Format(), tid);
+    LOG_WARNING(Service_ACC, "(STUBBED) called, uuid=0x{}, tid={:016X}", uuid.RawString(), tid);
     StoreSaveDataThumbnail(ctx, uuid, tid);
 }
 
@@ -903,7 +903,7 @@ void Module::Interface::StoreSaveDataThumbnail(Kernel::HLERequestContext& ctx,
         return;
     }
 
-    if (!uuid) {
+    if (uuid.IsInvalid()) {
         LOG_ERROR(Service_ACC, "User ID is not valid!");
         rb.Push(ERR_INVALID_USER_ID);
         return;
@@ -927,20 +927,20 @@ void Module::Interface::TrySelectUserWithoutInteraction(Kernel::HLERequestContex
     IPC::ResponseBuilder rb{ctx, 6};
     if (profile_manager->GetUserCount() != 1) {
         rb.Push(ResultSuccess);
-        rb.PushRaw<u128>(Common::INVALID_UUID);
+        rb.PushRaw(Common::InvalidUUID);
         return;
     }
 
     const auto user_list = profile_manager->GetAllUsers();
     if (std::ranges::all_of(user_list, [](const auto& user) { return user.IsInvalid(); })) {
         rb.Push(ResultUnknown); // TODO(ogniK): Find the correct error code
-        rb.PushRaw<u128>(Common::INVALID_UUID);
+        rb.PushRaw(Common::InvalidUUID);
         return;
     }
 
     // Select the first user we have
     rb.Push(ResultSuccess);
-    rb.PushRaw<u128>(profile_manager->GetUser(0)->uuid);
+    rb.PushRaw(profile_manager->GetUser(0)->uuid);
 }
 
 Module::Interface::Interface(std::shared_ptr<Module> module_,
diff --git a/src/core/hle/service/acc/profile_manager.cpp b/src/core/hle/service/acc/profile_manager.cpp
index 568303ced..fba847142 100644
--- a/src/core/hle/service/acc/profile_manager.cpp
+++ b/src/core/hle/service/acc/profile_manager.cpp
@@ -19,8 +19,8 @@ namespace FS = Common::FS;
 using Common::UUID;
 
 struct UserRaw {
-    UUID uuid{Common::INVALID_UUID};
-    UUID uuid2{Common::INVALID_UUID};
+    UUID uuid{};
+    UUID uuid2{};
     u64 timestamp{};
     ProfileUsername username{};
     ProfileData extra_data{};
@@ -45,7 +45,7 @@ ProfileManager::ProfileManager() {
 
     // Create an user if none are present
     if (user_count == 0) {
-        CreateNewUser(UUID::Generate(), "yuzu");
+        CreateNewUser(UUID::MakeRandom(), "yuzu");
     }
 
     auto current =
@@ -101,7 +101,7 @@ ResultCode ProfileManager::CreateNewUser(UUID uuid, const ProfileUsername& usern
     if (user_count == MAX_USERS) {
         return ERROR_TOO_MANY_USERS;
     }
-    if (!uuid) {
+    if (uuid.IsInvalid()) {
         return ERROR_ARGUMENT_IS_NULL;
     }
     if (username[0] == 0x0) {
@@ -145,7 +145,7 @@ std::optional<UUID> ProfileManager::GetUser(std::size_t index) const {
 
 /// Returns a users profile index based on their user id.
 std::optional<std::size_t> ProfileManager::GetUserIndex(const UUID& uuid) const {
-    if (!uuid) {
+    if (uuid.IsInvalid()) {
         return std::nullopt;
     }
 
@@ -250,9 +250,10 @@ UserIDArray ProfileManager::GetOpenUsers() const {
     std::ranges::transform(profiles, output.begin(), [](const ProfileInfo& p) {
         if (p.is_open)
             return p.user_uuid;
-        return UUID{Common::INVALID_UUID};
+        return Common::InvalidUUID;
     });
-    std::stable_partition(output.begin(), output.end(), [](const UUID& uuid) { return uuid; });
+    std::stable_partition(output.begin(), output.end(),
+                          [](const UUID& uuid) { return uuid.IsValid(); });
     return output;
 }
 
@@ -299,7 +300,7 @@ bool ProfileManager::RemoveUser(UUID uuid) {
 
     profiles[*index] = ProfileInfo{};
     std::stable_partition(profiles.begin(), profiles.end(),
-                          [](const ProfileInfo& profile) { return profile.user_uuid; });
+                          [](const ProfileInfo& profile) { return profile.user_uuid.IsValid(); });
     return true;
 }
 
@@ -361,7 +362,7 @@ void ProfileManager::ParseUserSaveFile() {
     }
 
     std::stable_partition(profiles.begin(), profiles.end(),
-                          [](const ProfileInfo& profile) { return profile.user_uuid; });
+                          [](const ProfileInfo& profile) { return profile.user_uuid.IsValid(); });
 }
 
 void ProfileManager::WriteUserSaveFile() {
diff --git a/src/core/hle/service/acc/profile_manager.h b/src/core/hle/service/acc/profile_manager.h
index 71b9d5518..17347f7ef 100644
--- a/src/core/hle/service/acc/profile_manager.h
+++ b/src/core/hle/service/acc/profile_manager.h
@@ -35,7 +35,7 @@ static_assert(sizeof(ProfileData) == 0x80, "ProfileData structure has incorrect
 /// This holds general information about a users profile. This is where we store all the information
 /// based on a specific user
 struct ProfileInfo {
-    Common::UUID user_uuid{Common::INVALID_UUID};
+    Common::UUID user_uuid{};
     ProfileUsername username{};
     u64 creation_time{};
     ProfileData data{}; // TODO(ognik): Work out what this is
@@ -49,7 +49,7 @@ struct ProfileBase {
 
     // Zero out all the fields to make the profile slot considered "Empty"
     void Invalidate() {
-        user_uuid.Invalidate();
+        user_uuid = {};
         timestamp = 0;
         username.fill(0);
     }
@@ -103,7 +103,7 @@ private:
 
     std::array<ProfileInfo, MAX_USERS> profiles{};
     std::size_t user_count{};
-    Common::UUID last_opened_user{Common::INVALID_UUID};
+    Common::UUID last_opened_user{};
 };
 
 }; // namespace Service::Account
diff --git a/src/core/hle/service/am/am.cpp b/src/core/hle/service/am/am.cpp
index e60661fe1..773dc9f29 100644
--- a/src/core/hle/service/am/am.cpp
+++ b/src/core/hle/service/am/am.cpp
@@ -55,7 +55,7 @@ constexpr u32 LAUNCH_PARAMETER_ACCOUNT_PRESELECTED_USER_MAGIC = 0xC79497CA;
 struct LaunchParameterAccountPreselectedUser {
     u32_le magic;
     u32_le is_account_selected;
-    u128 current_user;
+    Common::UUID current_user;
     INSERT_PADDING_BYTES(0x70);
 };
 static_assert(sizeof(LaunchParameterAccountPreselectedUser) == 0x88);
@@ -1453,8 +1453,8 @@ void IApplicationFunctions::PopLaunchParameter(Kernel::HLERequestContext& ctx) {
 
         Account::ProfileManager profile_manager{};
         const auto uuid = profile_manager.GetUser(static_cast<s32>(Settings::values.current_user));
-        ASSERT(uuid);
-        params.current_user = uuid->uuid;
+        ASSERT(uuid.has_value() && uuid->IsValid());
+        params.current_user = *uuid;
 
         IPC::ResponseBuilder rb{ctx, 2, 0, 1};
 
diff --git a/src/core/hle/service/am/applets/applet_profile_select.cpp b/src/core/hle/service/am/applets/applet_profile_select.cpp
index a6e891944..82500e121 100644
--- a/src/core/hle/service/am/applets/applet_profile_select.cpp
+++ b/src/core/hle/service/am/applets/applet_profile_select.cpp
@@ -62,11 +62,11 @@ void ProfileSelect::SelectionComplete(std::optional<Common::UUID> uuid) {
 
     if (uuid.has_value() && uuid->IsValid()) {
         output.result = 0;
-        output.uuid_selected = uuid->uuid;
+        output.uuid_selected = *uuid;
     } else {
         status = ERR_USER_CANCELLED_SELECTION;
         output.result = ERR_USER_CANCELLED_SELECTION.raw;
-        output.uuid_selected = Common::INVALID_UUID;
+        output.uuid_selected = Common::InvalidUUID;
     }
 
     final_data = std::vector<u8>(sizeof(UserSelectionOutput));
diff --git a/src/core/hle/service/am/applets/applet_profile_select.h b/src/core/hle/service/am/applets/applet_profile_select.h
index 8fb76e6c4..852e1e0c0 100644
--- a/src/core/hle/service/am/applets/applet_profile_select.h
+++ b/src/core/hle/service/am/applets/applet_profile_select.h
@@ -27,7 +27,7 @@ static_assert(sizeof(UserSelectionConfig) == 0xA0, "UserSelectionConfig has inco
 
 struct UserSelectionOutput {
     u64 result;
-    u128 uuid_selected;
+    Common::UUID uuid_selected;
 };
 static_assert(sizeof(UserSelectionOutput) == 0x18, "UserSelectionOutput has incorrect size.");
 
diff --git a/src/core/hle/service/friend/friend.cpp b/src/core/hle/service/friend/friend.cpp
index 9f9cea1e0..79cd3acbb 100644
--- a/src/core/hle/service/friend/friend.cpp
+++ b/src/core/hle/service/friend/friend.cpp
@@ -173,7 +173,7 @@ private:
         const auto uuid = rp.PopRaw<Common::UUID>();
 
         LOG_WARNING(Service_Friend, "(STUBBED) called, local_play={}, uuid=0x{}", local_play,
-                    uuid.Format());
+                    uuid.RawString());
 
         IPC::ResponseBuilder rb{ctx, 2};
         rb.Push(ResultSuccess);
@@ -186,7 +186,7 @@ private:
         [[maybe_unused]] const auto filter = rp.PopRaw<SizedFriendFilter>();
         const auto pid = rp.Pop<u64>();
         LOG_WARNING(Service_Friend, "(STUBBED) called, offset={}, uuid=0x{}, pid={}", friend_offset,
-                    uuid.Format(), pid);
+                    uuid.RawString(), pid);
 
         IPC::ResponseBuilder rb{ctx, 3};
         rb.Push(ResultSuccess);
@@ -312,7 +312,7 @@ void Module::Interface::CreateNotificationService(Kernel::HLERequestContext& ctx
     IPC::RequestParser rp{ctx};
     auto uuid = rp.PopRaw<Common::UUID>();
 
-    LOG_DEBUG(Service_Friend, "called, uuid=0x{}", uuid.Format());
+    LOG_DEBUG(Service_Friend, "called, uuid=0x{}", uuid.RawString());
 
     IPC::ResponseBuilder rb{ctx, 2, 0, 1};
     rb.Push(ResultSuccess);
diff --git a/src/core/hle/service/mii/mii_manager.cpp b/src/core/hle/service/mii/mii_manager.cpp
index ca4ed35bb..0a57c3cde 100644
--- a/src/core/hle/service/mii/mii_manager.cpp
+++ b/src/core/hle/service/mii/mii_manager.cpp
@@ -118,16 +118,6 @@ u16 GenerateCrc16(const void* data, std::size_t size) {
     return Common::swap16(static_cast<u16>(crc));
 }
 
-Common::UUID GenerateValidUUID() {
-    auto uuid{Common::UUID::Generate()};
-
-    // Bit 7 must be set, and bit 6 unset for the UUID to be valid
-    uuid.uuid[1] &= 0xFFFFFFFFFFFFFF3FULL;
-    uuid.uuid[1] |= 0x0000000000000080ULL;
-
-    return uuid;
-}
-
 template <typename T>
 T GetRandomValue(T min, T max) {
     std::random_device device;
@@ -383,7 +373,7 @@ MiiStoreData::MiiStoreData() = default;
 MiiStoreData::MiiStoreData(const MiiStoreData::Name& name, const MiiStoreBitFields& bit_fields,
                            const Common::UUID& user_id) {
     data.name = name;
-    data.uuid = GenerateValidUUID();
+    data.uuid = Common::UUID::MakeRandomRFC4122V4();
 
     std::memcpy(data.data.data(), &bit_fields, sizeof(MiiStoreBitFields));
     data_crc = GenerateCrc16(data.data.data(), sizeof(data));
diff --git a/src/core/hle/service/mii/mii_manager.h b/src/core/hle/service/mii/mii_manager.h
index 8e048fc56..6999d15b1 100644
--- a/src/core/hle/service/mii/mii_manager.h
+++ b/src/core/hle/service/mii/mii_manager.h
@@ -202,7 +202,7 @@ struct MiiStoreData {
         static_assert(sizeof(MiiStoreBitFields) == sizeof(data), "data field has incorrect size.");
 
         Name name{};
-        Common::UUID uuid{Common::INVALID_UUID};
+        Common::UUID uuid{};
     } data;
 
     u16 data_crc{};
@@ -326,7 +326,7 @@ public:
     ResultCode GetIndex(const MiiInfo& info, u32& index);
 
 private:
-    const Common::UUID user_id{Common::INVALID_UUID};
+    const Common::UUID user_id{};
     u64 update_counter{};
 };
 
diff --git a/src/core/hle/service/ns/pdm_qry.cpp b/src/core/hle/service/ns/pdm_qry.cpp
index e2fab5c3f..36ce46353 100644
--- a/src/core/hle/service/ns/pdm_qry.cpp
+++ b/src/core/hle/service/ns/pdm_qry.cpp
@@ -59,7 +59,7 @@ void PDM_QRY::QueryPlayStatisticsByApplicationIdAndUserAccountId(Kernel::HLERequ
 
     LOG_WARNING(Service_NS,
                 "(STUBBED) called. unknown={}. application_id=0x{:016X}, user_account_uid=0x{}",
-                unknown, application_id, user_account_uid.Format());
+                unknown, application_id, user_account_uid.RawString());
 
     IPC::ResponseBuilder rb{ctx, 12};
     rb.Push(ResultSuccess);
diff --git a/src/core/hle/service/time/clock_types.h b/src/core/hle/service/time/clock_types.h
index 392e16863..d0cacb80c 100644
--- a/src/core/hle/service/time/clock_types.h
+++ b/src/core/hle/service/time/clock_types.h
@@ -36,7 +36,7 @@ struct SteadyClockTimePoint {
     }
 
     static SteadyClockTimePoint GetRandom() {
-        return {0, Common::UUID::Generate()};
+        return {0, Common::UUID::MakeRandom()};
     }
 };
 static_assert(sizeof(SteadyClockTimePoint) == 0x18, "SteadyClockTimePoint is incorrect size");
diff --git a/src/core/hle/service/time/steady_clock_core.h b/src/core/hle/service/time/steady_clock_core.h
index d80a2385f..5ee2c0e0a 100644
--- a/src/core/hle/service/time/steady_clock_core.h
+++ b/src/core/hle/service/time/steady_clock_core.h
@@ -49,7 +49,7 @@ public:
     }
 
 private:
-    Common::UUID clock_source_id{Common::UUID::Generate()};
+    Common::UUID clock_source_id{Common::UUID::MakeRandom()};
     bool is_initialized{};
 };
 
diff --git a/src/core/hle/service/time/time_manager.cpp b/src/core/hle/service/time/time_manager.cpp
index c1e4e6cce..00f1ae8cf 100644
--- a/src/core/hle/service/time/time_manager.cpp
+++ b/src/core/hle/service/time/time_manager.cpp
@@ -45,7 +45,7 @@ struct TimeManager::Impl final {
           time_zone_content_manager{system} {
 
         const auto system_time{Clock::TimeSpanType::FromSeconds(GetExternalRtcValue())};
-        SetupStandardSteadyClock(system, Common::UUID::Generate(), system_time, {}, {});
+        SetupStandardSteadyClock(system, Common::UUID::MakeRandom(), system_time, {}, {});
         SetupStandardLocalSystemClock(system, {}, system_time.ToSeconds());
 
         Clock::SystemClockContext clock_context{};
diff --git a/src/input_common/drivers/gc_adapter.cpp b/src/input_common/drivers/gc_adapter.cpp
index 7ab4540a8..155caae42 100644
--- a/src/input_common/drivers/gc_adapter.cpp
+++ b/src/input_common/drivers/gc_adapter.cpp
@@ -248,7 +248,7 @@ bool GCAdapter::Setup() {
         std::size_t port = 0;
         for (GCController& pad : pads) {
             pad.identifier = {
-                .guid = Common::UUID{Common::INVALID_UUID},
+                .guid = Common::UUID{},
                 .port = port++,
                 .pad = 0,
             };
diff --git a/src/input_common/drivers/keyboard.cpp b/src/input_common/drivers/keyboard.cpp
index 4c1e5bbec..59e3d9cc0 100644
--- a/src/input_common/drivers/keyboard.cpp
+++ b/src/input_common/drivers/keyboard.cpp
@@ -9,17 +9,17 @@
 namespace InputCommon {
 
 constexpr PadIdentifier key_identifier = {
-    .guid = Common::UUID{Common::INVALID_UUID},
+    .guid = Common::UUID{},
     .port = 0,
     .pad = 0,
 };
 constexpr PadIdentifier keyboard_key_identifier = {
-    .guid = Common::UUID{Common::INVALID_UUID},
+    .guid = Common::UUID{},
     .port = 1,
     .pad = 0,
 };
 constexpr PadIdentifier keyboard_modifier_identifier = {
-    .guid = Common::UUID{Common::INVALID_UUID},
+    .guid = Common::UUID{},
     .port = 1,
     .pad = 1,
 };
diff --git a/src/input_common/drivers/mouse.cpp b/src/input_common/drivers/mouse.cpp
index d8ae7f0c1..3c9a4e747 100644
--- a/src/input_common/drivers/mouse.cpp
+++ b/src/input_common/drivers/mouse.cpp
@@ -20,7 +20,7 @@ constexpr int motion_wheel_y = 4;
 constexpr int touch_axis_x = 10;
 constexpr int touch_axis_y = 11;
 constexpr PadIdentifier identifier = {
-    .guid = Common::UUID{Common::INVALID_UUID},
+    .guid = Common::UUID{},
     .port = 0,
     .pad = 0,
 };
diff --git a/src/input_common/drivers/sdl_driver.cpp b/src/input_common/drivers/sdl_driver.cpp
index f54b91f9d..5cf1987ad 100644
--- a/src/input_common/drivers/sdl_driver.cpp
+++ b/src/input_common/drivers/sdl_driver.cpp
@@ -502,7 +502,7 @@ std::vector<Common::ParamPackage> SDLDriver::GetInputDevices() const {
 Common::Input::VibrationError SDLDriver::SetRumble(
     const PadIdentifier& identifier, const Common::Input::VibrationStatus& vibration) {
     const auto joystick =
-        GetSDLJoystickByGUID(identifier.guid.Format(), static_cast<int>(identifier.port));
+        GetSDLJoystickByGUID(identifier.guid.RawString(), static_cast<int>(identifier.port));
     const auto process_amplitude_exp = [](f32 amplitude, f32 factor) {
         return (amplitude + std::pow(amplitude, factor)) * 0.5f * 0xFFFF;
     };
@@ -599,7 +599,7 @@ Common::ParamPackage SDLDriver::BuildParamPackageForAnalog(PadIdentifier identif
     Common::ParamPackage params;
     params.Set("engine", GetEngineName());
     params.Set("port", static_cast<int>(identifier.port));
-    params.Set("guid", identifier.guid.Format());
+    params.Set("guid", identifier.guid.RawString());
     params.Set("axis_x", axis_x);
     params.Set("axis_y", axis_y);
     params.Set("offset_x", offset_x);
diff --git a/src/input_common/drivers/touch_screen.cpp b/src/input_common/drivers/touch_screen.cpp
index 880781825..30c727df4 100644
--- a/src/input_common/drivers/touch_screen.cpp
+++ b/src/input_common/drivers/touch_screen.cpp
@@ -8,7 +8,7 @@
 namespace InputCommon {
 
 constexpr PadIdentifier identifier = {
-    .guid = Common::UUID{Common::INVALID_UUID},
+    .guid = Common::UUID{},
     .port = 0,
     .pad = 0,
 };
diff --git a/src/input_common/drivers/udp_client.cpp b/src/input_common/drivers/udp_client.cpp
index 333173e3d..64162f431 100644
--- a/src/input_common/drivers/udp_client.cpp
+++ b/src/input_common/drivers/udp_client.cpp
@@ -353,7 +353,7 @@ PadIdentifier UDPClient::GetPadIdentifier(std::size_t pad_index) const {
 
 Common::UUID UDPClient::GetHostUUID(const std::string& host) const {
     const auto ip = boost::asio::ip::make_address_v4(host);
-    const auto hex_host = fmt::format("{:06x}", ip.to_uint());
+    const auto hex_host = fmt::format("00000000-0000-0000-0000-0000{:06x}", ip.to_uint());
     return Common::UUID{hex_host};
 }
 
@@ -385,7 +385,7 @@ std::vector<Common::ParamPackage> UDPClient::GetInputDevices() const {
             Common::ParamPackage identifier{};
             identifier.Set("engine", GetEngineName());
             identifier.Set("display", fmt::format("UDP Controller {}", pad_identifier.pad));
-            identifier.Set("guid", pad_identifier.guid.Format());
+            identifier.Set("guid", pad_identifier.guid.RawString());
             identifier.Set("port", static_cast<int>(pad_identifier.port));
             identifier.Set("pad", static_cast<int>(pad_identifier.pad));
             devices.emplace_back(identifier);
diff --git a/src/input_common/drivers/udp_client.h b/src/input_common/drivers/udp_client.h
index e9c178139..76e32bd04 100644
--- a/src/input_common/drivers/udp_client.h
+++ b/src/input_common/drivers/udp_client.h
@@ -126,7 +126,7 @@ private:
     struct ClientConnection {
         ClientConnection();
         ~ClientConnection();
-        Common::UUID uuid{"7F000001"};
+        Common::UUID uuid{"00000000-0000-0000-0000-00007F000001"};
         std::string host{"127.0.0.1"};
         u16 port{26760};
         s8 active{-1};
diff --git a/src/input_common/input_engine.cpp b/src/input_common/input_engine.cpp
index 0508b408d..65ae1b848 100644
--- a/src/input_common/input_engine.cpp
+++ b/src/input_common/input_engine.cpp
@@ -96,7 +96,7 @@ bool InputEngine::GetButton(const PadIdentifier& identifier, int button) const {
     std::lock_guard lock{mutex};
     const auto controller_iter = controller_list.find(identifier);
     if (controller_iter == controller_list.cend()) {
-        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.Format(),
+        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.RawString(),
                   identifier.pad, identifier.port);
         return false;
     }
@@ -113,7 +113,7 @@ bool InputEngine::GetHatButton(const PadIdentifier& identifier, int button, u8 d
     std::lock_guard lock{mutex};
     const auto controller_iter = controller_list.find(identifier);
     if (controller_iter == controller_list.cend()) {
-        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.Format(),
+        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.RawString(),
                   identifier.pad, identifier.port);
         return false;
     }
@@ -130,7 +130,7 @@ f32 InputEngine::GetAxis(const PadIdentifier& identifier, int axis) const {
     std::lock_guard lock{mutex};
     const auto controller_iter = controller_list.find(identifier);
     if (controller_iter == controller_list.cend()) {
-        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.Format(),
+        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.RawString(),
                   identifier.pad, identifier.port);
         return 0.0f;
     }
@@ -147,7 +147,7 @@ BatteryLevel InputEngine::GetBattery(const PadIdentifier& identifier) const {
     std::lock_guard lock{mutex};
     const auto controller_iter = controller_list.find(identifier);
     if (controller_iter == controller_list.cend()) {
-        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.Format(),
+        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.RawString(),
                   identifier.pad, identifier.port);
         return BatteryLevel::Charging;
     }
@@ -159,7 +159,7 @@ BasicMotion InputEngine::GetMotion(const PadIdentifier& identifier, int motion)
     std::lock_guard lock{mutex};
     const auto controller_iter = controller_list.find(identifier);
     if (controller_iter == controller_list.cend()) {
-        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.Format(),
+        LOG_ERROR(Input, "Invalid identifier guid={}, pad={}, port={}", identifier.guid.RawString(),
                   identifier.pad, identifier.port);
         return {};
     }
diff --git a/src/input_common/input_engine.h b/src/input_common/input_engine.h
index fe2faee5a..c6c027aef 100644
--- a/src/input_common/input_engine.h
+++ b/src/input_common/input_engine.h
@@ -16,7 +16,7 @@
 
 // Pad Identifier of data source
 struct PadIdentifier {
-    Common::UUID guid{Common::INVALID_UUID};
+    Common::UUID guid{};
     std::size_t port{};
     std::size_t pad{};
 
@@ -59,7 +59,7 @@ namespace std {
 template <>
 struct hash<PadIdentifier> {
     size_t operator()(const PadIdentifier& pad_id) const noexcept {
-        u64 hash_value = pad_id.guid.uuid[1] ^ pad_id.guid.uuid[0];
+        u64 hash_value = pad_id.guid.Hash();
         hash_value ^= (static_cast<u64>(pad_id.port) << 32);
         hash_value ^= static_cast<u64>(pad_id.pad);
         return static_cast<size_t>(hash_value);
diff --git a/src/input_common/input_mapping.cpp b/src/input_common/input_mapping.cpp
index a7a6ad8c2..fb78093b8 100644
--- a/src/input_common/input_mapping.cpp
+++ b/src/input_common/input_mapping.cpp
@@ -57,7 +57,7 @@ void MappingFactory::RegisterButton(const MappingData& data) {
     Common::ParamPackage new_input;
     new_input.Set("engine", data.engine);
     if (data.pad.guid.IsValid()) {
-        new_input.Set("guid", data.pad.guid.Format());
+        new_input.Set("guid", data.pad.guid.RawString());
     }
     new_input.Set("port", static_cast<int>(data.pad.port));
     new_input.Set("pad", static_cast<int>(data.pad.pad));
@@ -93,7 +93,7 @@ void MappingFactory::RegisterStick(const MappingData& data) {
     Common::ParamPackage new_input;
     new_input.Set("engine", data.engine);
     if (data.pad.guid.IsValid()) {
-        new_input.Set("guid", data.pad.guid.Format());
+        new_input.Set("guid", data.pad.guid.RawString());
     }
     new_input.Set("port", static_cast<int>(data.pad.port));
     new_input.Set("pad", static_cast<int>(data.pad.pad));
@@ -138,7 +138,7 @@ void MappingFactory::RegisterMotion(const MappingData& data) {
     Common::ParamPackage new_input;
     new_input.Set("engine", data.engine);
     if (data.pad.guid.IsValid()) {
-        new_input.Set("guid", data.pad.guid.Format());
+        new_input.Set("guid", data.pad.guid.RawString());
     }
     new_input.Set("port", static_cast<int>(data.pad.port));
     new_input.Set("pad", static_cast<int>(data.pad.pad));
diff --git a/src/yuzu/applets/qt_profile_select.cpp b/src/yuzu/applets/qt_profile_select.cpp
index 5b32da923..4cd8f7784 100644
--- a/src/yuzu/applets/qt_profile_select.cpp
+++ b/src/yuzu/applets/qt_profile_select.cpp
@@ -23,13 +23,13 @@ QString FormatUserEntryText(const QString& username, Common::UUID uuid) {
     return QtProfileSelectionDialog::tr(
                "%1\n%2", "%1 is the profile username, %2 is the formatted UUID (e.g. "
                          "00112233-4455-6677-8899-AABBCCDDEEFF))")
-        .arg(username, QString::fromStdString(uuid.FormatSwitch()));
+        .arg(username, QString::fromStdString(uuid.FormattedString()));
 }
 
 QString GetImagePath(Common::UUID uuid) {
     const auto path =
         Common::FS::GetYuzuPath(Common::FS::YuzuPath::NANDDir) /
-        fmt::format("system/save/8000000000000010/su/avators/{}.jpg", uuid.FormatSwitch());
+        fmt::format("system/save/8000000000000010/su/avators/{}.jpg", uuid.FormattedString());
     return QString::fromStdString(Common::FS::PathToUTF8String(path));
 }
 
diff --git a/src/yuzu/configuration/configure_profile_manager.cpp b/src/yuzu/configuration/configure_profile_manager.cpp
index 78b6374c0..d9f6dee4e 100644
--- a/src/yuzu/configuration/configure_profile_manager.cpp
+++ b/src/yuzu/configuration/configure_profile_manager.cpp
@@ -33,10 +33,10 @@ constexpr std::array<u8, 107> backup_jpeg{
     0x01, 0x01, 0x00, 0x00, 0x3f, 0x00, 0xd2, 0xcf, 0x20, 0xff, 0xd9,
 };
 
-QString GetImagePath(Common::UUID uuid) {
+QString GetImagePath(const Common::UUID& uuid) {
     const auto path =
         Common::FS::GetYuzuPath(Common::FS::YuzuPath::NANDDir) /
-        fmt::format("system/save/8000000000000010/su/avators/{}.jpg", uuid.FormatSwitch());
+        fmt::format("system/save/8000000000000010/su/avators/{}.jpg", uuid.FormattedString());
     return QString::fromStdString(Common::FS::PathToUTF8String(path));
 }
 
@@ -55,10 +55,10 @@ QString FormatUserEntryText(const QString& username, Common::UUID uuid) {
     return ConfigureProfileManager::tr("%1\n%2",
                                        "%1 is the profile username, %2 is the formatted UUID (e.g. "
                                        "00112233-4455-6677-8899-AABBCCDDEEFF))")
-        .arg(username, QString::fromStdString(uuid.FormatSwitch()));
+        .arg(username, QString::fromStdString(uuid.FormattedString()));
 }
 
-QPixmap GetIcon(Common::UUID uuid) {
+QPixmap GetIcon(const Common::UUID& uuid) {
     QPixmap icon{GetImagePath(uuid)};
 
     if (!icon) {
@@ -200,7 +200,7 @@ void ConfigureProfileManager::AddUser() {
         return;
     }
 
-    const auto uuid = Common::UUID::Generate();
+    const auto uuid = Common::UUID::MakeRandom();
     profile_manager->CreateNewUser(uuid, username.toStdString());
 
     item_model->appendRow(new QStandardItem{GetIcon(uuid), FormatUserEntryText(username, uuid)});
diff --git a/src/yuzu/main.cpp b/src/yuzu/main.cpp
index cc5a8f65e..3c2d7d080 100644
--- a/src/yuzu/main.cpp
+++ b/src/yuzu/main.cpp
@@ -1652,7 +1652,7 @@ void GMainWindow::OnGameListOpenFolder(u64 program_id, GameListOpenTarget target
 
             const auto user_save_data_path = FileSys::SaveDataFactory::GetFullPath(
                 *system, FileSys::SaveDataSpaceId::NandUser, FileSys::SaveDataType::SaveData,
-                program_id, user_id->uuid, 0);
+                program_id, user_id->AsU128(), 0);
 
             path = Common::FS::ConcatPathSafe(nand_dir, user_save_data_path);
         } else {