Index: usr.sbin/bhyve/pci_nvme.c
===================================================================
--- usr.sbin/bhyve/pci_nvme.c
+++ usr.sbin/bhyve/pci_nvme.c
@@ -365,6 +365,8 @@
 	cd->oncs = (NVME_CTRLR_DATA_ONCS_DSM_MASK << NVME_CTRLR_DATA_ONCS_DSM_SHIFT);
 	cd->fna = 0x03;
 
+	cd->vwc = 1 << NVME_CTRLR_DATA_VWC_PRESENT_SHIFT;
+
 	cd->power_state[0].mp = 10;
 }
 
@@ -979,6 +981,7 @@
 		break;
 	case NVME_FEAT_VOLATILE_WRITE_CACHE:
 		DPRINTF(("  volatile write cache\r\n"));
+		compl->cdw0 = 1;
 		break;
 	case NVME_FEAT_NUMBER_OF_QUEUES:
 		compl->cdw0 = NVME_FEATURE_NUM_QUEUES(sc);
@@ -1472,6 +1475,50 @@
 	return (err);
 }
 
+static int
+nvme_opc_flush(struct pci_nvme_softc *sc,
+    struct nvme_command *cmd,
+    struct pci_nvme_blockstore *nvstore,
+    struct pci_nvme_ioreq *req,
+    uint16_t *status)
+{
+	int err;
+
+	/* Check if the given nsid in command is out-of-range */
+	if ((!cmd->nsid || cmd->nsid > sc->ctrldata.nn) &&
+	    cmd->nsid != NVME_GLOBAL_NAMESPACE_TAG) {
+		pci_nvme_status_genc(status,
+		    NVME_SC_INVALID_NAMESPACE_OR_FORMAT);
+
+		return (1);
+	}
+
+	if (nvstore->type == NVME_STOR_RAM) {
+		uint16_t status;
+
+		pci_nvme_status_genc(&status, NVME_SC_SUCCESS);
+		pci_nvme_set_completion(sc, req->nvme_sq, req->sqid, cmd->cid, 0,
+		    status, 1);
+
+		return (0);
+	}
+
+	req->opc = cmd->opc;
+	req->cid = cmd->cid;
+	req->nsid = cmd->nsid;
+	req->io_req.br_iovcnt = 0;
+	req->io_req.br_offset = 0;
+	req->io_req.br_resid = 0;
+
+	req->io_req.br_callback = pci_nvme_io_done;
+
+	err = blockif_flush(sc->nvstore.ctx, &req->io_req);
+	if (err)
+		pci_nvme_status_genc(status, NVME_SC_INTERNAL_DEVICE_ERROR);
+
+	return (err);
+}
+
 static void
 pci_nvme_handle_io_cmd(struct pci_nvme_softc* sc, uint16_t idx)
 {
@@ -1506,13 +1553,7 @@
 
 		lba = ((uint64_t)cmd->cdw11 << 32) | cmd->cdw10;
 
-		if (cmd->opc == NVME_OPC_FLUSH) {
-			pci_nvme_status_genc(&status, NVME_SC_SUCCESS);
-			pci_nvme_set_completion(sc, sq, idx, cmd->cid, 0,
-			                        status, 1);
-
-			continue;
-		} else if (cmd->opc == 0x08) {
+		if (cmd->opc == 0x08) {
 			/* TODO: write zeroes */
 			WPRINTF(("%s write zeroes lba 0x%lx blocks %u\r\n",
 			        __func__, lba, cmd->cdw12 & 0xFFFF));
@@ -1529,7 +1570,15 @@
 			req->sqid = idx;
 		}
 
-		if (cmd->opc == NVME_OPC_DATASET_MANAGEMENT) {
+		if (cmd->opc == NVME_OPC_FLUSH) {
+			if (nvme_opc_flush(sc, cmd, &sc->nvstore, req,
+			    &status)) {
+				pci_nvme_set_completion(sc, sq, idx, cmd->cid,
+				    0, status, 1);
+				pci_nvme_release_ioreq(sc, req);
+			}
+			continue;
+		} else if (cmd->opc == NVME_OPC_DATASET_MANAGEMENT) {
 			if (nvme_opc_dataset_mgmt(sc, cmd, &sc->nvstore, req,
 			    &status)) {
 				pci_nvme_set_completion(sc, sq, idx, cmd->cid,