Fix "Gamer Profile not selected" when the controller is not on the first slot

The game binds the player to the slot their controller enumerated on, and the recomp's single profile only answered on slot 0. A pad landing anywhere else made every sign-in query report "not signed in", producing the error. Behind ac6_profile_always_signed_in (default on), profile queries for slots 1-3 now answer with the one profile, so it follows the player to whichever slot their hardware landed on.

thirdparty/rexglue-sdk/include/rex/kernel/xam/private.h

@@ -13,6 +13,12 @@ namespace xam {
 
 bool xeXamIsUIActive();
 
+// Profile-alias compat shim (ac6_profile_always_signed_in): while the cvar is on,
+// user indices 1-3 alias to 0 - the one synthetic profile answers for any
+// slot the player's pad landed on. Index 0 and invalid indices (>= 4) always
+// pass through. Defined in xam_user.cpp; declared here for the unit test.
+uint32_t XamEffectiveUserIndex(uint32_t user_index);
+
 rex::runtime::Export* RegisterExport_xam(rex::runtime::Export* export_entry);
 
 // Registration functions, one per file.

thirdparty/rexglue-sdk/src/kernel/xam/xam_user.cpp

@@ -25,6 +25,25 @@
 
 REXCVAR_DEFINE_UINT32(user_language, 1, "Kernel", "User's language ID");
 
+// COMPAT SHIM - revisit when multiplayer work starts.
+// The recomp has exactly ONE synthetic profile and it lives at user index 0,
+// but on a real 360 the user slot follows the controller port: a pad that
+// enumerates as XInput device 1-3 (wireless dongle, HOTAS enumerated first,
+// second pad) binds the player to that slot, the game queries THAT index,
+// reads "not signed in", and shows "Gamer Profile not selected". With this
+// on, user-index-keyed profile queries answer with the one profile, signed
+// in, for ANY index 0-3 - the same profile for all four, never four
+// profiles. The profile OBJECT stays singular and real (settings storage,
+// XUID, identity untouched); this is presentation-level aliasing only, which
+// is also why it must be revisited for multiplayer, where per-player
+// identity becomes real. XamUserCheckPrivilege is deliberately NOT aliased
+// (DLC licensing territory).
+REXCVAR_DEFINE_BOOL(ac6_profile_always_signed_in, true, "AC6/Fixes",
+                    "Answer profile queries for any user index 0-3 with the one synthetic "
+                    "profile, signed in. Fixes 'Gamer Profile not selected' when the pad "
+                    "enumerates at an XInput slot other than 0 (the Steam Input workaround's "
+                    "actual mechanism). Off restores index-0-only behaviour.");
+
 namespace rex {
 namespace kernel {
 namespace xam {
@@ -51,6 +70,16 @@ std::atomic<uint32_t> g_get_xuid_indices_seen{0};
 
 }  // namespace
 
+// The alias itself (declared in private.h for the unit test): valid indices
+// 0-3 all map to 0 while ac6_profile_always_signed_in is on; index 0 and
+// invalid indices (>= 4) always pass through, so error paths are unchanged.
+uint32_t XamEffectiveUserIndex(uint32_t user_index) {
+  if (user_index != 0 && user_index < 4 && REXCVAR_GET(ac6_profile_always_signed_in)) {
+    return 0;
+  }
+  return user_index;
+}
+
 ppc_hresult_result_t XamUserGetXUID_entry(ppc_u32_t user_index, ppc_u32_t type_mask,
                                           ppc_pu64_t xuid_ptr) {
   LogUserIndexOnce(g_get_xuid_indices_seen, "XamUserGetXUID", user_index);
@@ -59,10 +88,11 @@ ppc_hresult_result_t XamUserGetXUID_entry(ppc_u32_t user_index, ppc_u32_t type_m
   if (!xuid_ptr) {
     return X_E_INVALIDARG;
   }
+  const uint32_t effective_index = XamEffectiveUserIndex(user_index);
   uint32_t result = X_E_NO_SUCH_USER;
   uint64_t xuid = 0;
   if (user_index < 4) {
-    if (user_index == 0) {
+    if (effective_index == 0) {
       const auto& user_profile = REX_KERNEL_STATE()->user_profile();
       auto type = user_profile->type() & type_mask;
       if (type & (2 | 4)) {
@@ -86,7 +116,7 @@ ppc_u32_result_t XamUserGetSigninState_entry(ppc_u32_t user_index) {
   LogUserIndexOnce(g_signin_state_indices_seen, "XamUserGetSigninState", user_index);
   uint32_t signin_state = 0;
   if (user_index < 4) {
-    if (user_index == 0) {
+    if (XamEffectiveUserIndex(user_index) == 0) {
       const auto& user_profile = REX_KERNEL_STATE()->user_profile();
       signin_state = user_profile->signin_state();
     }
@@ -111,7 +141,7 @@ ppc_hresult_result_t XamUserGetSigninInfo_entry(ppc_u32_t user_index, ppc_u32_t
   }
 
   std::memset(info, 0, sizeof(X_USER_SIGNIN_INFO));
-  if (user_index) {
+  if (XamEffectiveUserIndex(user_index)) {
     return X_E_NO_SUCH_USER;
   }
 
@@ -128,7 +158,7 @@ ppc_u32_result_t XamUserGetName_entry(ppc_u32_t user_index, ppc_pchar_t buffer,
     return X_E_INVALIDARG;
   }
 
-  if (user_index) {
+  if (XamEffectiveUserIndex(user_index)) {
     return X_E_NO_SUCH_USER;
   }
 
@@ -233,7 +263,11 @@ uint32_t XamUserReadProfileSettingsEx(uint32_t title_id, uint32_t user_index, ui
   // Title ID = 0 means us.
   // 0xfffe07d1 = profile?
 
-  if (!xuids && user_index) {
+  // XamEffectiveUserIndex: profile settings are the "Gamer Profile" data the
+  // game actually reads per slot; aliasing signin state but failing these
+  // would leave the profile NOT following the player. The echoed
+  // out_setting->user_index below stays the index the game asked about.
+  if (!xuids && XamEffectiveUserIndex(user_index)) {
     // Only support user 0.
     if (overlapped) {
       REX_KERNEL_STATE()->CompleteOverlappedImmediate(
@@ -334,7 +368,9 @@ ppc_u32_result_t XamUserWriteProfileSettings_entry(ppc_u32_t title_id, ppc_u32_t
     return X_ERROR_INVALID_PARAMETER;
   }
 
-  if (user_index) {
+  // XamEffectiveUserIndex: the write side of the same aliasing as the read
+  // side above - there is only one profile object either way.
+  if (XamEffectiveUserIndex(user_index)) {
     // Only support user 0.
     if (overlapped) {
       REX_KERNEL_STATE()->CompleteOverlappedImmediate(overlapped.guest_address(),

thirdparty/rexglue-sdk/tests/unit/CMakeLists.txt

@@ -3,6 +3,7 @@
 add_executable(unit_tests
     memory/heap_allocation_test.cpp
     kernel/object_table_test.cpp
+    kernel/xam_user_alias_test.cpp
     core/cvar_test.cpp
     core/fiber_test.cpp
     core/sha256_test.cpp

thirdparty/rexglue-sdk/tests/unit/kernel/xam_user_alias_test.cpp

@@ -0,0 +1,62 @@
+/**
+ * @file        tests/unit/kernel/xam_user_alias_test.cpp
+ * @brief       Unit tests for the profile alias
+ *              (ac6_profile_always_signed_in / XamEffectiveUserIndex)
+ *
+ * @license     BSD 3-Clause License
+ *              See LICENSE file in the project root for full license text.
+ */
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <rex/cvar.h>
+#include <rex/kernel/xam/private.h>
+
+using rex::kernel::xam::XamEffectiveUserIndex;
+
+namespace {
+
+// RAII: force the cvar to a value for one section, restore the default after.
+struct ScopedCvar {
+  ScopedCvar(const char* name, const char* value) : name_(name) {
+    REQUIRE(rex::cvar::SetFlagByName(name_, value));
+  }
+  ~ScopedCvar() { rex::cvar::ResetToDefault(name_); }
+  const char* name_;
+};
+
+}  // namespace
+
+TEST_CASE("profile alias: cvar ON maps every valid nonzero index to the one profile",
+          "[xam][profile_alias]") {
+  ScopedCvar on("ac6_profile_always_signed_in", "true");
+
+  // The player's pad landed at slot 1/2/3: the profile follows the player.
+  CHECK(XamEffectiveUserIndex(0) == 0u);
+  CHECK(XamEffectiveUserIndex(1) == 0u);
+  CHECK(XamEffectiveUserIndex(2) == 0u);
+  CHECK(XamEffectiveUserIndex(3) == 0u);
+
+  // Invalid indices stay invalid: error paths are unchanged.
+  CHECK(XamEffectiveUserIndex(4) == 4u);
+  CHECK(XamEffectiveUserIndex(0xFF) == 0xFFu);
+}
+
+TEST_CASE("profile alias: cvar OFF restores index-0-only behaviour unchanged",
+          "[xam][profile_alias]") {
+  ScopedCvar off("ac6_profile_always_signed_in", "false");
+
+  CHECK(XamEffectiveUserIndex(0) == 0u);
+  CHECK(XamEffectiveUserIndex(1) == 1u);
+  CHECK(XamEffectiveUserIndex(2) == 2u);
+  CHECK(XamEffectiveUserIndex(3) == 3u);
+  CHECK(XamEffectiveUserIndex(4) == 4u);
+  CHECK(XamEffectiveUserIndex(0xFF) == 0xFFu);
+}
+
+TEST_CASE("profile alias: cvar ships default ON", "[xam][profile_alias]") {
+  const auto* info = rex::cvar::GetFlagInfo("ac6_profile_always_signed_in");
+  REQUIRE(info != nullptr);
+  CHECK(info->default_value == "true");
+  CHECK(info->category == "AC6/Fixes");
+}