For P2P, use the peer list when allocating Device memory or pinned host.

Each new allocation is automatically mapped into the address space of
all enabled peers.

include/hcc_detail/hip_hcc.h

@@ -35,6 +35,10 @@ THE SOFTWARE.
 //Use the new HCC accelerator_view::copy instead of am_copy
 #define USE_AV_COPY 0
 
+// Compile peer-to-peer support.
+// 2= use upcoming HCC APIs.
+#define USE_PEER_TO_PEER 1
+
 //#define INLINE static inline
 
 //---
@@ -523,7 +527,7 @@ public:
     bool removePeer(ihipDevice_t *peer);
 
     uint32_t peerCnt() const { return _peerCnt; };
-    uint32_t peerAgents() const { return _peerAgents; };
+    hsa_agent_t *peerAgents() const { return _peerAgents; };
 
 
 private:

include/hcc_detail/hip_runtime_api.h

@@ -919,19 +919,22 @@ hipError_t hipDeviceCanAccessPeer (int* canAccessPeer, int deviceId, int peerDev
  *
  * @param [in] peerDeviceId
  *
- * TODO:cudaErrorPeerAccessNotEnabled and cudaErrorInvalidDevice error not supported in HIP, return hipErrorUnknown
- * Returns #hipSuccess, #hipErrorUnknown
+ * Returns #hipSuccess, #hipErrorPeerAccessNotEnabled
  */
 hipError_t  hipDeviceDisablePeerAccess (int peerDeviceId);
 
 /**
  * @brief Enable direct access from current device's virtual address space to memory allocations physically located on a peer device.  
  *
+ * Memory which already allocated on peer device will be mapped into the address space of the current device.  In addition, all
+ * future memory allocations on peerDeviceId will be mapped into the address space of the current device when the memory is allocated.
+ * The peer memory remains accessible from the current device until a call to hipDeviceDisablePeerAccess or @hipDeviceReset.
+ *
+ *
  * @param [in] peerDeviceId
  * @param [in] flags
  *
- * TODO:cudaErrorInvalidDevice error not supported in HIP, return hipErrorUnknown
- * Returns #hipSuccess, #hipErrorInvalidDevice, #hipErrorInvalidValue, #hipErrorUnknown
+ * Returns #hipSuccess, #hipErrorInvalidDevice, #hipErrorInvalidValue, #hipErrorPeerAccessAlreadyEnabled
  */
 hipError_t  hipDeviceEnablePeerAccess (int  peerDeviceId, unsigned int flags);