[KV offload] Enable CPU KV offload on CUDA alike Platforms (#27770)

Signed-off-by: zhewenli <zhewenli@meta.com>

tests/v1/kv_offload/test_cpu_offloading.py

@@ -12,7 +12,6 @@ from tqdm import tqdm
 from vllm import LLM, SamplingParams, TokensPrompt
 from vllm.config import KVEventsConfig, KVTransferConfig
 from vllm.distributed.kv_events import BlockStored, KVEventBatch
-from vllm.platforms import current_platform
 
 CPU_BLOCK_SIZES = [16, 48]
 
@@ -64,9 +63,6 @@ class MockSubscriber:
         self.sub.close()
 
 
-@pytest.mark.skipif(
-    not current_platform.is_cuda(), reason="CPU offloading only supported on CUDA"
-)
 @pytest.mark.parametrize("cpu_block_size", CPU_BLOCK_SIZES)
 def test_cpu_offloading(cpu_block_size: int) -> None:
     """

vllm/v1/kv_offload/cpu.py

@@ -51,9 +51,9 @@ class CPUOffloadingSpec(OffloadingSpec):
         self, kv_caches: dict[str, torch.Tensor]
     ) -> Iterator[tuple[type[LoadStoreSpec], type[LoadStoreSpec], OffloadingHandler]]:
         if not self._handler:
-            if not current_platform.is_cuda():
+            if not current_platform.is_cuda_alike():
                 raise Exception(
-                    "CPU Offloading is currently only supported on CUDA GPUs"
+                    "CPU Offloading is currently only supported on CUDA-alike GPUs"
                 )
 
             layer_names = list(kv_caches.keys())