Checking for RDMA support before allocating via VMM in test suite

cuda_core/cuda/core/experimental/_memory.pyx

@@ -1119,7 +1119,7 @@ class VirtualMemoryResourceOptions:
     location_type: VirtualMemoryLocationTypeT = "device"
     handle_type: VirtualMemoryHandleTypeT = "posix_fd"
     granularity: VirtualMemoryGranularityT = "recommended"
-    gpu_direct_rdma: bool = True
+    gpu_direct_rdma: bool = False
     addr_hint: Optional[int] = 0
     addr_align: Optional[int] = None
     peers: Iterable[int] = field(default_factory=tuple)
@@ -1198,6 +1198,11 @@ class VirtualMemoryResource(MemoryResource):
         if platform.system() == "Windows":
             raise NotImplementedError("VirtualMemoryResource is not supported on Windows")
 
+        # Validate RDMA support if requested
+        if self.config.gpu_direct_rdma and self.device is not None:
+            if not self.device.properties.gpu_direct_rdma_supported:
+                raise RuntimeError("GPU Direct RDMA is not supported on this device")
+
     @staticmethod
     def _align_up(size: int, gran: int) -> int:
         """

cuda_core/tests/test_memory.py

@@ -28,7 +28,7 @@
 from cuda.core.experimental._utils.cuda_utils import handle_return
 from cuda.core.experimental.utils import StridedMemoryView
 
-from cuda_python_test_helpers import IS_WSL, supports_ipc_mempool
+from cuda_python_test_helpers import supports_ipc_mempool
 
 POOL_SIZE = 2097152  # 2MB size
 
@@ -322,13 +322,13 @@ def test_vmm_allocator_basic_allocation():
     This test verifies that VirtualMemoryResource can allocate memory
     using CUDA VMM APIs with default configuration.
     """
-    if platform.system() == "Windows":
-        pytest.skip("VirtualMemoryResource is not supported on Windows TCC")
-    if IS_WSL:
-        pytest.skip("VirtualMemoryResource is not supported on WSL")
-
     device = Device()
     device.set_current()
+
+    # Skip if virtual memory management is not supported
+    if not device.properties.virtual_memory_management_supported:
+        pytest.skip("Virtual memory management is not supported on this device")
+
     options = VirtualMemoryResourceOptions()
     # Create VMM allocator with default config
     vmm_mr = VirtualMemoryResource(device, config=options)
@@ -361,13 +361,17 @@ def test_vmm_allocator_policy_configuration():
     with different allocation policies and that the configuration affects
     the allocation behavior.
     """
-    if platform.system() == "Windows":
-        pytest.skip("VirtualMemoryResource is not supported on Windows TCC")
-    if IS_WSL:
-        pytest.skip("VirtualMemoryResource is not supported on WSL")
     device = Device()
     device.set_current()
 
+    # Skip if virtual memory management is not supported
+    if not device.properties.virtual_memory_management_supported:
+        pytest.skip("Virtual memory management is not supported on this device")
+
+    # Skip if GPU Direct RDMA is supported (we want to test the unsupported case)
+    if not device.properties.gpu_direct_rdma_supported:
+        pytest.skip("This test requires a device that doesn't support GPU Direct RDMA")
+
     # Test with custom VMM config
     custom_config = VirtualMemoryResourceOptions(
         allocation_type="pinned",
@@ -420,13 +424,13 @@ def test_vmm_allocator_grow_allocation():
     This test verifies that VirtualMemoryResource can grow existing
     allocations while preserving the base pointer when possible.
     """
-    if platform.system() == "Windows":
-        pytest.skip("VirtualMemoryResource is not supported on Windows TCC")
-    if IS_WSL:
-        pytest.skip("VirtualMemoryResource is not supported on WSL")
     device = Device()
     device.set_current()
 
+    # Skip if virtual memory management is not supported (we need it for VMM)
+    if not device.properties.virtual_memory_management_supported:
+        pytest.skip("Virtual memory management is not supported on this device")
+
     options = VirtualMemoryResourceOptions()
 
     vmm_mr = VirtualMemoryResource(device, config=options)
@@ -458,6 +462,29 @@ def test_vmm_allocator_grow_allocation():
     grown_buffer.close()
 
 
+def test_vmm_allocator_rdma_unsupported_exception():
+    """Test that VirtualMemoryResource throws an exception when RDMA is requested but device doesn't support it.
+
+    This test verifies that the VirtualMemoryResource constructor throws a RuntimeError
+    when gpu_direct_rdma=True is requested but the device doesn't support virtual memory management.
+    """
+    device = Device()
+    device.set_current()
+
+    # Skip if virtual memory management is not supported (we need it for VMM)
+    if not device.properties.virtual_memory_management_supported:
+        pytest.skip("Virtual memory management is not supported on this device")
+
+    # Skip if GPU Direct RDMA is supported (we want to test the unsupported case)
+    if device.properties.gpu_direct_rdma_supported:
+        pytest.skip("This test requires a device that doesn't support GPU Direct RDMA")
+
+    # Test that requesting RDMA on an unsupported device throws an exception
+    options = VirtualMemoryResourceOptions(gpu_direct_rdma=True)
+    with pytest.raises(RuntimeError, match="GPU Direct RDMA is not supported on this device"):
+        VirtualMemoryResource(device, config=options)
+
+
 def test_mempool(mempool_device):
     device = mempool_device