Add virtual memory support: PE_MMU, VA allocator, fabric MmuMapMsg

Implement VA/MMU layer (ADR-0011 Phase 1) enabling Triton kernels to use
contiguous virtual addresses on sharded tensors.

Key changes:
- PE_MMU component: hybrid inbox (MmuMapMsg) + sync translate() for PE_DMA
- VirtualAllocator + PEMemAllocator: free-list with coalescing
- MmuMapMsg/MmuUnmapMsg fabric path with SIP-level routing
- DPPolicy-based mapping: replicate=local, sharded=broadcast
- Tensor lifecycle: del + weakref cleanup, context manager
- Rename: TensorHandle.pa→addr, DmaReadCmd.src_pa→src_addr, ctx→torch

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/kernbench/runtime_api/tensor.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import math
+import weakref
 from dataclasses import dataclass
 from typing import Literal
 
@@ -26,6 +27,7 @@ class TensorHandle:
     dtype: str
     itemsize: int
     shards: tuple[TensorShard, ...]
+    va_base: int = 0  # VA base address for the entire tensor
 
     @property
     def nbytes(self) -> int:
@@ -56,8 +58,19 @@ def deploy_tensor(
     placement: list[ShardSpec],
     allocators: dict[int, PEMemAllocator],
     mem_kind: Literal["hbm", "tcm"] = "hbm",
+    va_allocator=None,
+    mmus: dict | None = None,
 ) -> TensorHandle:
+    from kernbench.policy.address.pe_mmu import PeMMU
+
     isize = dtype_itemsize(dtype)
+    total_nbytes = math.prod(shape) * isize
+
+    # Allocate VA range for the entire tensor (if VA allocator provided)
+    va_base = 0
+    if va_allocator is not None:
+        va_base = va_allocator.alloc(total_nbytes)
+
     shards: list[TensorShard] = []
     for spec in placement:
         alloc = allocators[spec.pe_index]
@@ -65,20 +78,29 @@ def deploy_tensor(
             pa = alloc.alloc_hbm(spec.nbytes)
         else:
             pa = alloc.alloc_tcm(spec.nbytes)
+        encoded_pa = pa.encode()
         shards.append(TensorShard(
             sip=alloc._sip_id,
             cube=alloc._cube_id,
             pe=alloc._pe_id,
-            pa=pa.encode(),
+            pa=encoded_pa,
             nbytes=spec.nbytes,
             offset_bytes=spec.offset_bytes,
         ))
+
+        # Register VA→PA mapping in all MMUs (broadcast)
+        if va_base and mmus is not None:
+            shard_va = va_base + spec.offset_bytes
+            for mmu in mmus.values():
+                mmu.map(va=shard_va, pa=encoded_pa, size=spec.nbytes)
+
     return TensorHandle(
         name=name,
         shape=shape,
         dtype=dtype,
         itemsize=isize,
         shards=tuple(shards),
+        va_base=va_base,
     )
 
 
@@ -101,8 +123,7 @@ class Tensor:
 
     Usage::
 
-        a = ctx.zeros((M, K), dtype="f16")
-        a = ctx.zeros((M, K), dtype="f16", placement=dp.replicate(num_pe=8))
+        a = ctx.zeros((M, K), dtype="f16", dp=DPPolicy(cube="replicate", pe="replicate"))
         ctx.launch("kernel_name", kernel_fn, a, b, out, M=M, K=K)
     """
 
@@ -117,6 +138,14 @@ class Tensor:
         self.name = name
         self._dp_metadata: DPMetadata | None = None
         self._handle: TensorHandle | None = None
+        self._ctx_ref: weakref.ref | None = None  # set by RuntimeContext
+
+    def __del__(self) -> None:
+        if self._ctx_ref is None or self._handle is None:
+            return
+        ctx = self._ctx_ref()
+        if ctx is not None:
+            ctx._free_tensor(self)
 
     @property
     def itemsize(self) -> int:
@@ -133,6 +162,13 @@ class Tensor:
             raise RuntimeError(f"Tensor '{self.name}' is not deployed yet")
         return self._handle.shards[0].pa
 
+    @property
+    def va(self) -> int:
+        """VA base address for the entire tensor."""
+        if self._handle is None:
+            raise RuntimeError(f"Tensor '{self.name}' is not deployed yet")
+        return self._handle.va_base
+
     def to(
         self,
         placement: list[ShardSpec] | None = None,
@@ -163,4 +199,5 @@ class Tensor:
                 )
                 for s in self._handle.shards
             ),
+            va_base=self._handle.va_base,
         )