meta-arm/meta-arm/recipes-security/trusted-services/files/0022-Change-MM-communicate-RPC-protocol-of-call-endpoint.patch

From 0f02f04c7f0a7130874dc4bc1a500604d580c4dc Mon Sep 17 00:00:00 2001
From: Imre Kis <imre.kis@arm.com>
Date: Wed, 20 Jul 2022 15:19:17 +0200
Subject: [PATCH 22/24] Change MM communicate RPC protocol of call endpoint

Replace buffer address and size parameter by offset in buffer parameter
and move to 64 bit FF-A direct message call. Deny all 32 bit direct
messages in SMM gateway.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I7a69b440ff9842960229b2bfdd1b5ae5318d9c26

Upstream-Status: Pending [In review]
Signed-off-by: Anton Antonov <Anton.Antonov@arm.com>

---
 .../common/mm_communicate_call_args.h         |  15 ++-
 .../endpoint/sp/mm_communicate_call_ep.c      |  58 ++++-----
 .../endpoint/sp/test/mock_mm_service.cpp      |   6 +-
 .../endpoint/sp/test/mock_mm_service.h        |   4 +-
 .../sp/test/test_mm_communicate_call_ep.cpp   | 110 +++++++++++-------
 .../endpoint/sp/test/test_mock_mm_service.cpp |   4 +-
 .../smm-gateway/common/smm_gateway_sp.c       |  17 ++-
 7 files changed, 123 insertions(+), 91 deletions(-)

diff --git a/components/rpc/mm_communicate/common/mm_communicate_call_args.h b/components/rpc/mm_communicate/common/mm_communicate_call_args.h
index 7d7311d..280c04d 100644
--- a/components/rpc/mm_communicate/common/mm_communicate_call_args.h
+++ b/components/rpc/mm_communicate/common/mm_communicate_call_args.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: BSD-3-Clause */
 /*
- * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved.
  */
 
 #ifndef MM_COMMUNICATE_CALL_ARGS_H_
@@ -12,13 +12,12 @@
  */
 
 /* SP message arg indexes */
-#define MM_COMMUNICATE_CALL_ARGS_COMM_BUFFER_ADDRESS	0
-#define MM_COMMUNICATE_CALL_ARGS_COMM_BUFFER_SIZE	1
+#define MM_COMMUNICATE_CALL_ARGS_COMM_BUFFER_OFFSET	0
 
-#define MM_COMMUNICATE_CALL_ARGS_RETURN_ID		0
-#define MM_COMMUNICATE_CALL_ARGS_RETURN_CODE		1
-#define MM_COMMUNICATE_CALL_ARGS_MBZ0			2
-#define MM_COMMUNICATE_CALL_ARGS_MBZ1			3
-#define MM_COMMUNICATE_CALL_ARGS_MBZ2			4
+#define MM_COMMUNICATE_CALL_ARGS_RETURN_CODE		0
+#define MM_COMMUNICATE_CALL_ARGS_MBZ0			1
+#define MM_COMMUNICATE_CALL_ARGS_MBZ1			2
+#define MM_COMMUNICATE_CALL_ARGS_MBZ2			3
+#define MM_COMMUNICATE_CALL_ARGS_MBZ3			4
 
 #endif /* MM_COMMUNICATE_CALL_ARGS_H_ */
diff --git a/components/rpc/mm_communicate/endpoint/sp/mm_communicate_call_ep.c b/components/rpc/mm_communicate/endpoint/sp/mm_communicate_call_ep.c
index dc49e64..93aa0f4 100644
--- a/components/rpc/mm_communicate/endpoint/sp/mm_communicate_call_ep.c
+++ b/components/rpc/mm_communicate/endpoint/sp/mm_communicate_call_ep.c
@@ -35,7 +35,8 @@ bool mm_communicate_call_ep_init(struct mm_communicate_ep *call_ep, uint8_t *com
 
 static int32_t invoke_mm_service(struct mm_communicate_ep *call_ep, uint16_t source_id,
 				 struct mm_service_interface *iface,
-				 EFI_MM_COMMUNICATE_HEADER *header)
+				 EFI_MM_COMMUNICATE_HEADER *header,
+				 size_t buffer_size)
 {
 	rpc_status_t rpc_status = TS_RPC_ERROR_INTERNAL;
 	struct mm_service_call_req call_req = { 0 };
@@ -49,11 +50,11 @@ static int32_t invoke_mm_service(struct mm_communicate_ep *call_ep, uint16_t sou
 	 */
 	call_req.req_buf.data = header->Data;
 	call_req.req_buf.data_len = header->MessageLength;
-	call_req.req_buf.size = call_ep->comm_buffer_size - EFI_MM_COMMUNICATE_HEADER_SIZE;
+	call_req.req_buf.size = buffer_size;
 
 	call_req.resp_buf.data = header->Data;
 	call_req.resp_buf.data_len = 0;
-	call_req.resp_buf.size = call_ep->comm_buffer_size - EFI_MM_COMMUNICATE_HEADER_SIZE;
+	call_req.resp_buf.size = buffer_size;
 
 	result = iface->receive(iface, &call_req);
 
@@ -63,32 +64,38 @@ static int32_t invoke_mm_service(struct mm_communicate_ep *call_ep, uint16_t sou
 }
 
 static int32_t handle_mm_communicate(struct mm_communicate_ep *call_ep, uint16_t source_id,
-				     uintptr_t buffer_addr, size_t buffer_size)
+				     size_t buffer_offset)
 {
-	uintptr_t buffer_arg = 0;
-	size_t request_size = 0;
+	size_t header_end_offset = 0;
+	size_t request_end_offset = 0;
+	size_t buffer_size = 0;
 	EFI_MM_COMMUNICATE_HEADER *header = NULL;
 	unsigned int i = 0;
 
-	/* Validating call args according to ARM MM spec 3.2.4 */
-	if (buffer_addr == 0)
+	if (ADD_OVERFLOW(buffer_offset, EFI_MM_COMMUNICATE_HEADER_SIZE, &header_end_offset))
+		return MM_RETURN_CODE_INVALID_PARAMETER;
+
+	if (call_ep->comm_buffer_size < header_end_offset)
 		return MM_RETURN_CODE_INVALID_PARAMETER;
 
 	/* Validating comm buffer contents */
-	header = (EFI_MM_COMMUNICATE_HEADER *)call_ep->comm_buffer;
-	if (ADD_OVERFLOW(header->MessageLength, EFI_MM_COMMUNICATE_HEADER_SIZE, &request_size))
+	header = (EFI_MM_COMMUNICATE_HEADER *)(call_ep->comm_buffer + buffer_offset);
+	if (ADD_OVERFLOW(header_end_offset, header->MessageLength, &request_end_offset))
 		return MM_RETURN_CODE_INVALID_PARAMETER;
 
-	if (call_ep->comm_buffer_size < request_size)
+	if (call_ep->comm_buffer_size < request_end_offset)
 		return MM_RETURN_CODE_INVALID_PARAMETER;
 
+	buffer_size = call_ep->comm_buffer_size - header_end_offset;
+
 	/* Finding iface_id by GUID */
 	for (i = 0; i < ARRAY_SIZE(call_ep->service_table); i++) {
 		const struct mm_service_entry *entry = &call_ep->service_table[i];
 
 		if (entry->iface != NULL &&
 		    memcmp(&header->HeaderGuid, &entry->guid, sizeof(entry->guid)) == 0)
-			return invoke_mm_service(call_ep, source_id, entry->iface, header);
+			return invoke_mm_service(call_ep, source_id, entry->iface, header,
+						 buffer_size);
 	}
 
 	return MM_RETURN_CODE_NOT_SUPPORTED;
@@ -123,19 +130,16 @@ void mm_communicate_call_ep_receive(struct mm_communicate_ep *mm_communicate_cal
 				    const struct ffa_direct_msg *req_msg,
 				    struct ffa_direct_msg *resp_msg)
 {
-	int32_t return_value = 0;
-	uintptr_t buffer_address = 0;
-	size_t buffer_size = 0;
-
-	buffer_address = req_msg->args.args32[MM_COMMUNICATE_CALL_ARGS_COMM_BUFFER_ADDRESS];
-	buffer_size = req_msg->args.args32[MM_COMMUNICATE_CALL_ARGS_COMM_BUFFER_SIZE];
-
-	return_value = handle_mm_communicate(mm_communicate_call_ep, req_msg->source_id,
-					     buffer_address, buffer_size);
-
-	resp_msg->args.args32[MM_COMMUNICATE_CALL_ARGS_RETURN_ID] = ARM_SVC_ID_SP_EVENT_COMPLETE;
-	resp_msg->args.args32[MM_COMMUNICATE_CALL_ARGS_RETURN_CODE] = return_value;
-	resp_msg->args.args32[MM_COMMUNICATE_CALL_ARGS_MBZ0] = 0;
-	resp_msg->args.args32[MM_COMMUNICATE_CALL_ARGS_MBZ1] = 0;
-	resp_msg->args.args32[MM_COMMUNICATE_CALL_ARGS_MBZ2] = 0;
+	int32_t return_value = MM_RETURN_CODE_NOT_SUPPORTED;
+	size_t buffer_offset = req_msg->args.args64[MM_COMMUNICATE_CALL_ARGS_COMM_BUFFER_OFFSET];
+
+	return_value = handle_mm_communicate(mm_communicate_call_ep,
+						req_msg->source_id,
+						buffer_offset);
+
+	resp_msg->args.args64[MM_COMMUNICATE_CALL_ARGS_RETURN_CODE] = return_value;
+	resp_msg->args.args64[MM_COMMUNICATE_CALL_ARGS_MBZ0] = 0;
+	resp_msg->args.args64[MM_COMMUNICATE_CALL_ARGS_MBZ1] = 0;
+	resp_msg->args.args64[MM_COMMUNICATE_CALL_ARGS_MBZ2] = 0;
+	resp_msg->args.args64[MM_COMMUNICATE_CALL_ARGS_MBZ3] = 0;
 }
diff --git a/components/rpc/mm_communicate/endpoint/sp/test/mock_mm_service.cpp b/components/rpc/mm_communicate/endpoint/sp/test/mock_mm_service.cpp
index a58c33a..0ae2a80 100644
--- a/components/rpc/mm_communicate/endpoint/sp/test/mock_mm_service.cpp
+++ b/components/rpc/mm_communicate/endpoint/sp/test/mock_mm_service.cpp
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: BSD-3-Clause
 /*
- * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved.
  */
 
 #include <CppUTestExt/MockSupport.h>
@@ -16,7 +16,7 @@ void mock_mm_service_init(void)
 
 void expect_mock_mm_service_receive(struct mm_service_interface *iface,
 				    const struct mm_service_call_req *req,
-				    int32_t result)
+				    int64_t result)
 {
 	mock().expectOneCall("mm_service_receive").onObject(iface).
 		withOutputParameterReturning("resp_buf_data_len", &req->resp_buf.data_len,
@@ -31,5 +31,5 @@ int32_t mock_mm_service_receive(struct mm_service_interface *iface,
 	return mock().actualCall("mm_service_receive").onObject(iface).
 		withOutputParameter("resp_buf_data_len", &req->resp_buf.data_len).
 		withParameterOfType("mm_service_call_req", "req", req).
-		returnIntValue();
+		returnLongIntValue();
 }
diff --git a/components/rpc/mm_communicate/endpoint/sp/test/mock_mm_service.h b/components/rpc/mm_communicate/endpoint/sp/test/mock_mm_service.h
index 768022d..56c8a26 100644
--- a/components/rpc/mm_communicate/endpoint/sp/test/mock_mm_service.h
+++ b/components/rpc/mm_communicate/endpoint/sp/test/mock_mm_service.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: BSD-3-Clause */
 /*
- * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved.
  */
 
 #ifndef MOCK_MM_SERVICE_H_
@@ -16,7 +16,7 @@ void mock_mm_service_init(void);
 
 void expect_mock_mm_service_receive(struct mm_service_interface *iface,
 				    const struct mm_service_call_req *req,
-				    int32_t result);
+				    int64_t result);
 
 int32_t mock_mm_service_receive(struct mm_service_interface *iface,
 				struct mm_service_call_req *req);
diff --git a/components/rpc/mm_communicate/endpoint/sp/test/test_mm_communicate_call_ep.cpp b/components/rpc/mm_communicate/endpoint/sp/test/test_mm_communicate_call_ep.cpp
index 55a61fb..5aaa3a6 100644
--- a/components/rpc/mm_communicate/endpoint/sp/test/test_mm_communicate_call_ep.cpp
+++ b/components/rpc/mm_communicate/endpoint/sp/test/test_mm_communicate_call_ep.cpp
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: BSD-3-Clause
 /*
- * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved.
  */
 
 #include <CppUTest/TestHarness.h>
@@ -32,14 +32,14 @@ TEST_GROUP(mm_communicate_call_ep)
 		mock().clear();
 	}
 
-	void check_sp_msg(const struct ffa_direct_msg *msg, uint32_t arg0,
-			  uint32_t arg1, uint32_t arg2, uint32_t arg3, uint32_t arg4)
+	void check_sp_msg(const struct ffa_direct_msg *msg, uint64_t arg0,
+			  uint64_t arg1, uint64_t arg2, uint64_t arg3, uint64_t arg4)
 	{
-		UNSIGNED_LONGLONGS_EQUAL(arg0, msg->args[0]);
-		UNSIGNED_LONGLONGS_EQUAL(arg1, msg->args[1]);
-		UNSIGNED_LONGLONGS_EQUAL(arg2, msg->args[2]);
-		UNSIGNED_LONGLONGS_EQUAL(arg3, msg->args[3]);
-		UNSIGNED_LONGLONGS_EQUAL(arg4,  msg->args[4]);
+		UNSIGNED_LONGLONGS_EQUAL(arg0, msg->args.args64[0]);
+		UNSIGNED_LONGLONGS_EQUAL(arg1, msg->args.args64[1]);
+		UNSIGNED_LONGLONGS_EQUAL(arg2, msg->args.args64[2]);
+		UNSIGNED_LONGLONGS_EQUAL(arg3, msg->args.args64[3]);
+		UNSIGNED_LONGLONGS_EQUAL(arg4,  msg->args.args64[4]);
 	}
 
 	struct mm_communicate_ep call_ep;
@@ -114,59 +114,54 @@ TEST(mm_communicate_call_ep, attach_do_not_fit)
 	}
 }
 
-TEST(mm_communicate_call_ep, mm_communicate_no_buffer_arg)
+TEST(mm_communicate_call_ep, mm_communicate_offset_int_overflow)
 {
 	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
+	req_msg.args.args64[0] = 0xffffffffffffffff;
 
 	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	check_sp_msg(&resp_msg, ARM_SVC_ID_SP_EVENT_COMPLETE, MM_RETURN_CODE_INVALID_PARAMETER,
-		     0, 0, 0);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_INVALID_PARAMETER, 0, 0, 0, 0);
 }
 
-TEST(mm_communicate_call_ep, mm_communicate_length_overflow)
+TEST(mm_communicate_call_ep, mm_communicate_offset_overflow)
 {
 	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
+	req_msg.args.args64[0] = sizeof(comm_buffer) - EFI_MM_COMMUNICATE_HEADER_SIZE + 1;
+
+	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	req_msg.args[0] = (uintptr_t)comm_buffer;
-	req_msg.args[1] = sizeof(comm_buffer);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_INVALID_PARAMETER, 0, 0, 0, 0);
+}
 
+TEST(mm_communicate_call_ep, mm_communicate_length_overflow)
+{
+	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
 	header->MessageLength = UINT64_MAX - EFI_MM_COMMUNICATE_HEADER_SIZE + 1;
 
 	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	check_sp_msg(&resp_msg, ARM_SVC_ID_SP_EVENT_COMPLETE, MM_RETURN_CODE_INVALID_PARAMETER,
-		     0, 0, 0);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_INVALID_PARAMETER, 0, 0, 0, 0);
 }
 
 TEST(mm_communicate_call_ep, mm_communicate_too_large)
 {
 	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
-
-	req_msg.args[0] = (uintptr_t)comm_buffer;
-	req_msg.args[1] = sizeof(comm_buffer);
-
 	header->MessageLength = sizeof(comm_buffer) - EFI_MM_COMMUNICATE_HEADER_SIZE + 1;
 
 	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	check_sp_msg(&resp_msg, ARM_SVC_ID_SP_EVENT_COMPLETE, MM_RETURN_CODE_INVALID_PARAMETER,
-		     0, 0, 0);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_INVALID_PARAMETER, 0, 0, 0, 0);
 }
 
 TEST(mm_communicate_call_ep, mm_communicate_no_handler)
 {
 	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
-
-	req_msg.args[0] = (uintptr_t)comm_buffer;
-	req_msg.args[1] = sizeof(comm_buffer);
-
 	header->MessageLength = 0;
 
 	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	check_sp_msg(&resp_msg, ARM_SVC_ID_SP_EVENT_COMPLETE, MM_RETURN_CODE_NOT_SUPPORTED,
-		     0, 0, 0);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_NOT_SUPPORTED, 0, 0, 0, 0);
 }
 
 TEST(mm_communicate_call_ep, mm_communicate_single_handler_not_matching)
@@ -175,16 +170,11 @@ TEST(mm_communicate_call_ep, mm_communicate_single_handler_not_matching)
 
 	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
 	mm_communicate_call_ep_attach_service(&call_ep, &guid0, &iface);
-
-	req_msg.args[0] = (uintptr_t)comm_buffer;
-	req_msg.args[1] = sizeof(comm_buffer);
-
 	header->MessageLength = 0;
 
 	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	check_sp_msg(&resp_msg, ARM_SVC_ID_SP_EVENT_COMPLETE, MM_RETURN_CODE_NOT_SUPPORTED,
-		     0, 0, 0);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_NOT_SUPPORTED, 0, 0, 0, 0);
 }
 
 TEST(mm_communicate_call_ep, mm_communicate_single_handler_matching)
@@ -211,19 +201,55 @@ TEST(mm_communicate_call_ep, mm_communicate_single_handler_matching)
 	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
 	mm_communicate_call_ep_attach_service(&call_ep, &guid0, &iface);
 
-	req_msg.args[0] = (uintptr_t)comm_buffer;
-	req_msg.args[1] = sizeof(comm_buffer);
+	memcpy(&header->HeaderGuid, &guid0, sizeof(guid0));
+	header->MessageLength = req_len;
+
+	expect_mock_mm_service_receive(&iface, &req, MM_RETURN_CODE_SUCCESS);
+
+	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
+
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_SUCCESS, 0, 0, 0, 0);
+}
+
+TEST(mm_communicate_call_ep, mm_communicate_single_handler_matching_with_offset)
+{
+	const size_t offset = 0x10;
+	EFI_MM_COMMUNICATE_HEADER *header = (EFI_MM_COMMUNICATE_HEADER *)(comm_buffer + offset);
+
+	const size_t req_len = 16;
+	struct mm_service_interface iface = {
+		.context = (void *)0x1234,
+		.receive = mock_mm_service_receive
+	};
+	struct mm_service_call_req req = {
+		.guid = &guid0,
+		.req_buf = {
+			.size = sizeof(comm_buffer) - EFI_MM_COMMUNICATE_HEADER_SIZE - offset,
+			.data_len = req_len,
+			.data = header->Data
+		},
+		.resp_buf = {
+			.size = sizeof(comm_buffer) - EFI_MM_COMMUNICATE_HEADER_SIZE - offset,
+			.data_len = 0,
+			.data = header->Data
+		},
+	};
+
+	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
+	mm_communicate_call_ep_attach_service(&call_ep, &guid0, &iface);
 
 	memcpy(&header->HeaderGuid, &guid0, sizeof(guid0));
 	header->MessageLength = req_len;
+	req_msg.args.args64[0] = offset;
 
 	expect_mock_mm_service_receive(&iface, &req, MM_RETURN_CODE_SUCCESS);
 
 	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	check_sp_msg(&resp_msg, ARM_SVC_ID_SP_EVENT_COMPLETE, MM_RETURN_CODE_SUCCESS, 0, 0, 0);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_SUCCESS, 0, 0, 0, 0);
 }
 
+
 TEST(mm_communicate_call_ep, mm_communicate_single_handler_matching_error)
 {
 	const size_t req_len = 16;
@@ -248,9 +274,6 @@ TEST(mm_communicate_call_ep, mm_communicate_single_handler_matching_error)
 	CHECK_TRUE(mm_communicate_call_ep_init(&call_ep, comm_buffer, sizeof(comm_buffer)));
 	mm_communicate_call_ep_attach_service(&call_ep, &guid0, &iface);
 
-	req_msg.args[0] = (uintptr_t)comm_buffer;
-	req_msg.args[1] = sizeof(comm_buffer);
-
 	memcpy(&header->HeaderGuid, &guid0, sizeof(guid0));
 	header->MessageLength = req_len;
 
@@ -258,7 +281,7 @@ TEST(mm_communicate_call_ep, mm_communicate_single_handler_matching_error)
 
 	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	check_sp_msg(&resp_msg, ARM_SVC_ID_SP_EVENT_COMPLETE, MM_RETURN_CODE_NO_MEMORY, 0, 0, 0);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_NO_MEMORY, 0, 0, 0, 0);
 }
 
 TEST(mm_communicate_call_ep, mm_communicate_two_handlers)
@@ -290,9 +313,6 @@ TEST(mm_communicate_call_ep, mm_communicate_two_handlers)
 	mm_communicate_call_ep_attach_service(&call_ep, &guid0, &iface0);
 	mm_communicate_call_ep_attach_service(&call_ep, &guid1, &iface1);
 
-	req_msg.args[0] = (uintptr_t)comm_buffer;
-	req_msg.args[1] = sizeof(comm_buffer);
-
 	memcpy(&header->HeaderGuid, &guid1, sizeof(guid0));
 	header->MessageLength = req_len;
 
@@ -300,5 +320,5 @@ TEST(mm_communicate_call_ep, mm_communicate_two_handlers)
 
 	mm_communicate_call_ep_receive(&call_ep, &req_msg, &resp_msg);
 
-	check_sp_msg(&resp_msg, ARM_SVC_ID_SP_EVENT_COMPLETE, MM_RETURN_CODE_SUCCESS, 0, 0, 0);
+	check_sp_msg(&resp_msg, MM_RETURN_CODE_SUCCESS, 0, 0, 0, 0);
 }
diff --git a/components/rpc/mm_communicate/endpoint/sp/test/test_mock_mm_service.cpp b/components/rpc/mm_communicate/endpoint/sp/test/test_mock_mm_service.cpp
index 360a8fa..600386e 100644
--- a/components/rpc/mm_communicate/endpoint/sp/test/test_mock_mm_service.cpp
+++ b/components/rpc/mm_communicate/endpoint/sp/test/test_mock_mm_service.cpp
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: BSD-3-Clause
 /*
- * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved.
  */
 
 #include <CppUTest/TestHarness.h>
@@ -44,7 +44,7 @@ TEST(mock_mm_service, receive)
 			.data = (void *)0x2345
 		}
 	};
-	int32_t result = -123456;
+	int64_t result = -123456;
 
 	expect_mock_mm_service_receive(&iface, &req, result);
 	LONGS_EQUAL(result, mock_mm_service_receive(&iface, &req));
diff --git a/deployments/smm-gateway/common/smm_gateway_sp.c b/deployments/smm-gateway/common/smm_gateway_sp.c
index 3697b7f..3062877 100644
--- a/deployments/smm-gateway/common/smm_gateway_sp.c
+++ b/deployments/smm-gateway/common/smm_gateway_sp.c
@@ -11,6 +11,7 @@
 #include "components/rpc/mm_communicate/endpoint/sp/mm_communicate_call_ep.h"
 #include "components/service/smm_variable/frontend/mm_communicate/smm_variable_mm_service.h"
 #include "platform/interface/memory_region.h"
+#include "protocols/common/mm/mm_smc.h"
 #include <ffa_api.h>
 #include <sp_api.h>
 #include <sp_messaging.h>
@@ -68,12 +69,20 @@ void __noreturn sp_main(struct ffa_init_info *init_info)
 	ffa_msg_wait(&req_msg);
 
 	while (1) {
+		if (FFA_IS_32_BIT_FUNC(req_msg.function_id)) {
+			EMSG("MM communicate over 32 bit FF-A messages is not supported");
+			ffa_msg_send_direct_resp_32(req_msg.destination_id, req_msg.source_id,
+						    MM_RETURN_CODE_NOT_SUPPORTED, 0, 0, 0, 0,
+						    &req_msg);
+			continue;
+		}
+
 		mm_communicate_call_ep_receive(&mm_communicate_call_ep, &req_msg, &resp_msg);
 
-		ffa_msg_send_direct_resp_32(req_msg.destination_id,
-					 req_msg.source_id, resp_msg.args.args32[0],
-					 resp_msg.args.args32[1], resp_msg.args.args32[2],
-					 resp_msg.args.args32[3], resp_msg.args.args32[4],
+		ffa_msg_send_direct_resp_64(req_msg.destination_id,
+					 req_msg.source_id, resp_msg.args.args64[0],
+					 resp_msg.args.args64[1], resp_msg.args.args64[2],
+					 resp_msg.args.args64[3], resp_msg.args.args64[4],
 					 &req_msg);
 	}
 
-- 
2.17.1