diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c
--- a/sys/dev/nvme/nvme_ctrlr.c
+++ b/sys/dev/nvme/nvme_ctrlr.c
@@ -730,6 +730,7 @@
 	aer->ctrlr = ctrlr;
 	req = nvme_allocate_request_null(M_WAITOK, nvme_ctrlr_async_event_cb,
 	    aer);
+	req->payload_read = true;
 	aer->req = req;
 	aer->log_page_id = 0;		/* Not a valid page */
 
@@ -1320,6 +1321,7 @@
 	*req = nvme_allocate_request_null(M_WAITOK, cb_fn, cb_arg);
 	(*req)->payload = memdesc_vmpages(upages, len, addr & PAGE_MASK);
 	(*req)->payload_valid = true;
+	(*req)->payload_read = is_read;
 	return (0);
 }
 
@@ -1373,9 +1375,11 @@
 			    nvme_pt_done, pt);
 			if (ret != 0)
 				return (ret);
-		} else
+		} else {
 			req = nvme_allocate_request_vaddr(pt->buf, pt->len,
 			    M_WAITOK, nvme_pt_done, pt);
+			req->payload_read = pt->is_read;
+		}
 	} else
 		req = nvme_allocate_request_null(M_WAITOK, nvme_pt_done, pt);
 
@@ -1456,10 +1460,12 @@
 			    &req, nvme_npc_done, npc);
 			if (ret != 0)
 				return (ret);
-		} else
+		} else {
 			req = nvme_allocate_request_vaddr(
 			    (void *)(uintptr_t)npc->addr, npc->data_len,
 			    M_WAITOK, nvme_npc_done, npc);
+			req->payload_read = npc->opcode & 0x1;
+		}
 	} else
 		req = nvme_allocate_request_null(M_WAITOK, nvme_npc_done, npc);
 
diff --git a/sys/dev/nvme/nvme_ctrlr_cmd.c b/sys/dev/nvme/nvme_ctrlr_cmd.c
--- a/sys/dev/nvme/nvme_ctrlr_cmd.c
+++ b/sys/dev/nvme/nvme_ctrlr_cmd.c
@@ -38,7 +38,7 @@
 
 	req = nvme_allocate_request_vaddr(payload,
 	    sizeof(struct nvme_controller_data), M_WAITOK, cb_fn, cb_arg);
-
+	req->payload_read = true;
 	cmd = &req->cmd;
 	cmd->opc = NVME_OPC_IDENTIFY;
 
@@ -60,6 +60,7 @@
 
 	req = nvme_allocate_request_vaddr(payload,
 	    sizeof(struct nvme_namespace_data), M_WAITOK, cb_fn, cb_arg);
+	req->payload_read = true;
 
 	cmd = &req->cmd;
 	cmd->opc = NVME_OPC_IDENTIFY;
@@ -265,6 +266,7 @@
 	 */
 	req = nvme_allocate_request_vaddr(payload, payload_size,
 	    M_NOWAIT, cb_fn, cb_arg);
+	req->payload_read = true;
 
 	cmd = &req->cmd;
 	cmd->opc = NVME_OPC_GET_LOG_PAGE;
diff --git a/sys/dev/nvme/nvme_ns_cmd.c b/sys/dev/nvme/nvme_ns_cmd.c
--- a/sys/dev/nvme/nvme_ns_cmd.c
+++ b/sys/dev/nvme/nvme_ns_cmd.c
@@ -39,6 +39,7 @@
 	    lba_count * nvme_ns_get_sector_size(ns), M_NOWAIT, cb_fn, cb_arg);
 	if (req == NULL)
 		return (ENOMEM);
+	req->payload_read = true;
 
 	nvme_ns_read_cmd(&req->cmd, ns->id, lba, lba_count);
 
@@ -58,6 +59,7 @@
 	req = nvme_allocate_request_bio(bp, M_NOWAIT, cb_fn, cb_arg);
 	if (req == NULL)
 		return (ENOMEM);
+	req->payload_read = true;
 	lba = bp->bio_offset / nvme_ns_get_sector_size(ns);
 	lba_count = bp->bio_bcount / nvme_ns_get_sector_size(ns);
 	nvme_ns_read_cmd(&req->cmd, ns->id, lba, lba_count);
@@ -77,6 +79,7 @@
 	    lba_count * nvme_ns_get_sector_size(ns), M_NOWAIT, cb_fn, cb_arg);
 	if (req == NULL)
 		return (ENOMEM);
+	req->payload_read = false;
 
 	nvme_ns_write_cmd(&req->cmd, ns->id, lba, lba_count);
 
@@ -96,6 +99,7 @@
 	req = nvme_allocate_request_bio(bp, M_NOWAIT, cb_fn, cb_arg);
 	if (req == NULL)
 		return (ENOMEM);
+	req->payload_read = false;
 	lba = bp->bio_offset / nvme_ns_get_sector_size(ns);
 	lba_count = bp->bio_bcount / nvme_ns_get_sector_size(ns);
 	nvme_ns_write_cmd(&req->cmd, ns->id, lba, lba_count);
@@ -117,6 +121,7 @@
 	    cb_arg);
 	if (req == NULL)
 		return (ENOMEM);
+	req->payload_read = false;
 
 	cmd = &req->cmd;
 	cmd->opc = NVME_OPC_DATASET_MANAGEMENT;
@@ -163,7 +168,7 @@
 	    nvme_completion_poll_cb, &status);
 	if (req == NULL)
 		return (ENOMEM);
-
+	req->payload_read = false;
 	cmd = &req->cmd;
 
 	if (len > 0) {
diff --git a/sys/dev/nvme/nvme_private.h b/sys/dev/nvme/nvme_private.h
--- a/sys/dev/nvme/nvme_private.h
+++ b/sys/dev/nvme/nvme_private.h
@@ -115,7 +115,7 @@
 	int32_t				retries;
 	bool				payload_valid;
 	bool				timeout;
-	bool				spare[2];		/* Future use */
+	bool				payload_read;
 	STAILQ_ENTRY(nvme_request)	stailq;
 };
 
diff --git a/sys/dev/nvme/nvme_qpair.c b/sys/dev/nvme/nvme_qpair.c
--- a/sys/dev/nvme/nvme_qpair.c
+++ b/sys/dev/nvme/nvme_qpair.c
@@ -237,9 +237,10 @@
 
 	if (!retry) {
 		if (req->payload_valid) {
+			bus_dmasync_op_t op = req->payload_read ?
+			    BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE;
 			bus_dmamap_sync(qpair->dma_tag_payload,
-			    tr->payload_dma_map,
-			    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
+			    tr->payload_dma_map, op);
 		}
 		if (req->cb_fn)
 			req->cb_fn(req->cb_arg, cpl);
@@ -1116,8 +1117,11 @@
 		tr->req->cmd.prp2 = 0;
 	}
 
-	bus_dmamap_sync(tr->qpair->dma_tag_payload, tr->payload_dma_map,
-	    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
+	if (tr->req->payload_valid) {
+		bus_dmamap_sync(tr->qpair->dma_tag_payload, tr->payload_dma_map,
+		    tr->req->payload_read ?
+		    BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
+	}
 	nvme_qpair_submit_tracker(tr->qpair, tr);
 }
 
diff --git a/sys/dev/nvme/nvme_sim.c b/sys/dev/nvme/nvme_sim.c
--- a/sys/dev/nvme/nvme_sim.c
+++ b/sys/dev/nvme/nvme_sim.c
@@ -99,6 +99,7 @@
 	payload = nvmeio->data_ptr;
 	size = nvmeio->dxfer_len;
 	/* SG LIST ??? */
+	/* We only support NONE, IN, or OUT transactions, but not BOTH */
 	if ((nvmeio->ccb_h.flags & CAM_DATA_MASK) == CAM_DATA_BIO)
 		req = nvme_allocate_request_bio((struct bio *)payload,
 		    M_NOWAIT, nvme_sim_nvmeio_done, ccb);
@@ -116,6 +117,8 @@
 		xpt_done(ccb);
 		return;
 	}
+	if (payload != NULL)
+		req->payload_read = (nvmeio->ccb_h.flags & CAM_DIR_IN) != 0;
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 
 	memcpy(&req->cmd, &ccb->nvmeio.cmd, sizeof(ccb->nvmeio.cmd));