cuda.core: report host accessibility for NUMA-located VMM resources (#2503)

`VirtualMemoryResource.__init__` classifies "host", "host_numa" and
"host_numa_current" all as host-located (it clears `self.device` for
each), but `is_host_accessible` compared with `== "host"`. A resource
configured with `location_type="host_numa"` or `"host_numa_current"`
therefore reported `is_host_accessible is False` *and*
`is_device_accessible is False` -- an impossible answer that propagates
to `Buffer.is_host_accessible`, which forwards to the memory resource.

Share a single `_HOST_LOCATION_TYPES` set between the constructor and
the property so the two classifications cannot drift again.

Author: LeSingh1

cuda_core/cuda/core/_memory/_virtual_memory_resource.py

@@ -33,6 +33,16 @@
 
 __all__ = ["VirtualMemoryResource", "VirtualMemoryResourceOptions"]
 
+# Location types whose physical backing lives in host memory. Shared by
+# VirtualMemoryResource.__init__ and is_host_accessible so the two cannot drift.
+_HOST_LOCATION_TYPES = frozenset(
+    {
+        VirtualMemoryLocationType.HOST,
+        VirtualMemoryLocationType.HOST_NUMA,
+        VirtualMemoryLocationType.HOST_NUMA_CURRENT,
+    }
+)
+
 
 @dataclass
 class VirtualMemoryResourceOptions:
@@ -169,8 +179,7 @@ def __init__(self, device_id: Device | int, config: VirtualMemoryResourceOptions
         self.config: VirtualMemoryResourceOptions = check_or_create_options(  # type: ignore[assignment]
             VirtualMemoryResourceOptions, config, "VirtualMemoryResource options", keep_none=False
         )
-        # Matches ("host", "host_numa", "host_numa_current")
-        if "host" in self.config.location_type:
+        if self.config.location_type in _HOST_LOCATION_TYPES:
             self.device = None
 
         if not self.device and self.config.location_type == "device":
@@ -609,7 +618,7 @@ def is_host_accessible(self) -> bool:
         """
         Indicates whether the allocated memory is accessible from the host.
         """
-        return self.config.location_type == "host"
+        return self.config.location_type in _HOST_LOCATION_TYPES
 
     @property
     def device_id(self) -> int:

cuda_core/tests/test_memory.py

@@ -1875,6 +1875,23 @@ def test_vmm_options_handle_type_win32_raises():
         VirtualMemoryResourceOptions._handle_type_to_driver("win32")
 
 
+@pytest.mark.agent_authored(model="claude-opus-5")
+@pytest.mark.parametrize("location_type", ["host", "host_numa", "host_numa_current"])
+def test_vmm_host_location_types_report_host_accessible(location_type):
+    """Every host-backed location type reports is_host_accessible.
+
+    __init__ classifies "host", "host_numa" and "host_numa_current" alike when
+    deciding the resource is not bound to a device, so is_host_accessible must
+    agree; otherwise a NUMA-located resource claims to be neither host- nor
+    device-accessible.
+    """
+    device = Device()
+    device.set_current()
+    mr = VirtualMemoryResource(device, config=VirtualMemoryResourceOptions(location_type=location_type))
+    assert mr.device is None
+    assert mr.is_host_accessible is True
+
+
 def test_device_memory_resource_peer_accessible_by_non_owned(mempool_device):
     """peer_accessible_by on a non-owned (default) DMR queries the driver live."""
     dev = mempool_device