[SYCL][UR] Make v2 adapter default for BMG and newer

Whenever we detect ANY device newer than BMG on
the platform we will use V2, otherwise we will use V1.

The default behavior can still be overwritten by setting
SYCL_UR_USE_LEVEL_ZERO_V2=1 to use V2 adapter or
SYCL_UR_USE_LEVEL_ZERO_V2=0 to use V1 adapter.

Author: igchor

unified-runtime/source/adapters/level_zero/adapter.cpp

@@ -258,6 +258,51 @@ ur_result_t adapterStateInit() {
   return UR_RESULT_SUCCESS;
 }
 
+static bool isBMGorNewer() {
+  auto urResult = checkDeviceIntelGPUIpVersionOrNewer(0x05004000);
+  if (urResult != UR_RESULT_SUCCESS &&
+      urResult != UR_RESULT_ERROR_UNSUPPORTED_VERSION) {
+    UR_LOG(ERR, "Intel GPU IP Version check failed: {}\n", urResult);
+    throw urResult;
+  }
+
+  return urResult == UR_RESULT_SUCCESS;
+}
+
+// returns a pair indicating whether to use the V1 adapter and a string
+// indicating the reason for the decision.
+static std::pair<bool, std::string> shouldUseV1Adapter() {
+  auto specificAdapterVersionRequested =
+      ur_getenv("UR_LOADER_USE_LEVEL_ZERO_V2").has_value() ||
+      ur_getenv("SYCL_UR_USE_LEVEL_ZERO_V2").has_value();
+
+  auto v2Requested = getenv_tobool("UR_LOADER_USE_LEVEL_ZERO_V2", false);
+  v2Requested |= getenv_tobool("SYCL_UR_USE_LEVEL_ZERO_V2", false);
+
+  std::string reason =
+      specificAdapterVersionRequested
+          ? "Specific adapter version requested by UR_LOADER_USE_LEVEL_ZERO_V2 "
+            "or SYCL_UR_USE_LEVEL_ZERO_V2"
+          : "Using default adapter version based on device IP version";
+
+  if (v2Requested) {
+    return {false, reason};
+  }
+
+  if (!v2Requested && specificAdapterVersionRequested) {
+    // v1 specifically requested
+    return {true, reason};
+  }
+
+  // default: only enable for devices older than BMG
+  return {!isBMGorNewer(), reason};
+}
+
+static std::pair<bool, std::string> shouldUseV2Adapter() {
+  auto [useV1, reason] = shouldUseV1Adapter();
+  return {!useV1, reason};
+}
+
 /*
 This constructor initializes the `ur_adapter_handle_t_` object and
 sets up the environment for Level Zero (L0) initialization.
@@ -471,6 +516,22 @@ ur_adapter_handle_t_::ur_adapter_handle_t_()
       return;
     }
 
+#ifdef UR_ADAPTER_LEVEL_ZERO_V2
+    auto [useV2, reason] = shouldUseV2Adapter();
+    if (!useV2) {
+      UR_LOG(INFO, "Skipping L0 V2 adapter: {}", reason);
+      result = std::move(platforms);
+      return;
+    }
+#else
+    auto [useV1, reason] = shouldUseV1Adapter();
+    if (!useV1) {
+      UR_LOG(INFO, "Skipping L0 V1 adapter: {}", reason);
+      result = std::move(platforms);
+      return;
+    }
+#endif
+
     // Check if the user has enabled the default L0 SysMan initialization.
     const int UrSysmanZesinitEnable = [&UserForcedSysManInit] {
       const char *UrRet = std::getenv("UR_L0_ENABLE_ZESINIT_DEFAULT");

unified-runtime/source/loader/ur_adapter_registry.hpp

@@ -355,22 +355,6 @@ class AdapterRegistry {
     }
 
     for (const auto &adapterName : adapterNames) {
-      // Skip legacy L0 adapter if the v2 adapter is requested, and vice versa.
-      if (std::string(adapterName).find("level_zero") != std::string::npos) {
-        auto v2Requested = getenv_tobool("UR_LOADER_USE_LEVEL_ZERO_V2", false);
-        v2Requested |= getenv_tobool("SYCL_UR_USE_LEVEL_ZERO_V2", false);
-        auto v2Adapter =
-            std::string(adapterName).find("v2") != std::string::npos;
-
-        if (v2Requested != v2Adapter) {
-          UR_LOG(INFO, "The adapter '{}' is skipped because {} {}.",
-                 adapterName,
-                 "UR_LOADER_USE_LEVEL_ZERO_V2 or SYCL_UR_USE_LEVEL_ZERO_V2",
-                 v2Requested ? "is set" : "is not set");
-          continue;
-        }
-      }
-
       std::vector<fs::path> loadPaths;
 
       // Adapter search order: