diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index 5d6e525..89ef9c2 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -276,7 +276,8 @@ struct hv_ref_tsc_page {
 /* Define synthetic interrupt controller message constants. */
 #define HV_MESSAGE_SIZE			(256)
 #define HV_MESSAGE_PAYLOAD_BYTE_COUNT	(240)
-#define HV_MESSAGE_PAYLOAD_QWORD_COUNT	(30)
+
+#define HV_MESSAGE_FLAG_PENDING		(1)
 
 /* Define hypervisor message types. */
 enum hv_message_type {
@@ -308,42 +309,19 @@ enum hv_message_type {
 	HVMSG_X64_LEGACY_FP_ERROR		= 0x80010005
 };
 
-/* Define synthetic interrupt controller message flags. */
-union hv_message_flags {
-	__u8 asu8;
-	struct {
-		__u8 msg_pending:1;
-		__u8 reserved:7;
-	};
-};
-
-/* Define port identifier type. */
-union hv_port_id {
-	__u32 asu32;
-	struct {
-		__u32 id:24;
-		__u32 reserved:8;
-	} u;
-};
-
 /* Define synthetic interrupt controller message header. */
 struct hv_message_header {
 	__u32 message_type;
 	__u8 payload_size;
-	union hv_message_flags message_flags;
+	__u8 message_flags;
 	__u8 reserved[2];
-	union {
-		__u64 sender;
-		union hv_port_id port;
-	};
+	__u64 origination_id;
 };
 
 /* Define synthetic interrupt controller message format. */
 struct hv_message {
 	struct hv_message_header header;
-	union {
-		__u64 payload[HV_MESSAGE_PAYLOAD_QWORD_COUNT];
-	} u;
+	__u64 payload[HV_MESSAGE_PAYLOAD_BYTE_COUNT / 8];
 };
 
 /* Define the synthetic interrupt message page layout. */
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 8ce6d64..87713cc 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -260,7 +260,7 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 	 */
 	mb();
 
-	if (msg->header.message_flags.msg_pending) {
+	if (msg->header.message_flags & HV_MESSAGE_FLAG_PENDING) {
 		/*
 		 * This will cause message queue rescan to
 		 * possibly deliver another msg from the
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index c7db112..546dddc 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -137,7 +137,7 @@ static void synic_clear_sint_msg_pending(struct kvm_vcpu_hv_synic *synic,
 	msg_page = kmap_atomic(page);
 
 	msg = &msg_page->sint_message[sint];
-	msg->header.message_flags.msg_pending = 0;
+	msg->header.message_flags &= ~HV_MESSAGE_FLAG_PENDING;
 
 	kunmap_atomic(msg_page);
 	kvm_release_page_dirty(page);
@@ -564,10 +564,10 @@ static int synic_deliver_msg(struct kvm_vcpu_hv_synic *synic, u32 sint,
 	dst_msg = &msg_page->sint_message[sint];
 	if (sync_cmpxchg(&dst_msg->header.message_type, HVMSG_NONE,
 			 src_msg->header.message_type) != HVMSG_NONE) {
-		dst_msg->header.message_flags.msg_pending = 1;
+		dst_msg->header.message_flags |= HV_MESSAGE_FLAG_PENDING;
 		r = -EAGAIN;
 	} else {
-		memcpy(&dst_msg->u.payload, &src_msg->u.payload,
+		memcpy(&dst_msg->payload, &src_msg->payload,
 		       src_msg->header.payload_size);
 		dst_msg->header.message_type = src_msg->header.message_type;
 		dst_msg->header.payload_size = src_msg->header.payload_size;
@@ -588,7 +588,7 @@ static int stimer_send_msg(struct kvm_vcpu_hv_stimer *stimer)
 	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);
 	struct hv_message *msg = &stimer->msg;
 	struct hv_timer_message_payload *payload =
-			(struct hv_timer_message_payload *)&msg->u.payload;
+			(struct hv_timer_message_payload *)&msg->payload;
 
 	payload->expiration_time = stimer->exp_time;
 	payload->delivery_time = get_time_ref_counter(vcpu->kvm);
@@ -653,7 +653,7 @@ static void stimer_prepare_msg(struct kvm_vcpu_hv_stimer *stimer)
 {
 	struct hv_message *msg = &stimer->msg;
 	struct hv_timer_message_payload *payload =
-			(struct hv_timer_message_payload *)&msg->u.payload;
+			(struct hv_timer_message_payload *)&msg->payload;
 
 	memset(&msg->header, 0, sizeof(msg->header));
 	msg->header.message_type = HVMSG_TIMER_EXPIRED;
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 4a5cc11..3576a0b 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -680,7 +680,7 @@ static void vmbus_wait_for_unload(void)
 				continue;
 
 			hdr = (struct vmbus_channel_message_header *)
-				msg->u.payload;
+				msg->payload;
 
 			if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
 				complete(&vmbus_connection.unload_event);
@@ -1071,14 +1071,14 @@ void vmbus_onmessage(void *context)
 	struct vmbus_channel_message_header *hdr;
 	int size;
 
-	hdr = (struct vmbus_channel_message_header *)msg->u.payload;
+	hdr = (struct vmbus_channel_message_header *)msg->payload;
 	size = msg->header.payload_size;
 
 	if (hdr->msgtype >= CHANNELMSG_COUNT) {
 		pr_err("Received invalid channel message type %d size %d\n",
 			   hdr->msgtype, size);
 		print_hex_dump_bytes("", DUMP_PREFIX_NONE,
-				     (unsigned char *)msg->u.payload, size);
+				     (unsigned char *)msg->payload, size);
 		return;
 	}
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index f6b626b..60571a8 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -883,7 +883,7 @@ void vmbus_on_msg_dpc(unsigned long data)
 		/* no msg */
 		return;
 
-	hdr = (struct vmbus_channel_message_header *)msg->u.payload;
+	hdr = (struct vmbus_channel_message_header *)msg->payload;
 
 	if (hdr->msgtype >= CHANNELMSG_COUNT) {
 		WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
