diff --git a/docs/system/devices/nvme.rst b/docs/system/devices/nvme.rst
index aba2533..30f841e 100644
--- a/docs/system/devices/nvme.rst
+++ b/docs/system/devices/nvme.rst
@@ -104,8 +104,8 @@
 .. code-block:: console
 
    -device nvme-subsys,id=nvme-subsys-0,nqn=subsys0
-   -device nvme,serial=a,subsys=nvme-subsys-0
-   -device nvme,serial=b,subsys=nvme-subsys-0
+   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
+   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
 
 This will create an NVM subsystem with two controllers. Having controllers
 linked to an ``nvme-subsys`` device allows additional ``nvme-ns`` parameters:
diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index ca335dd..533ad14 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -264,6 +264,7 @@
     [NVME_ADM_CMD_ASYNC_EV_REQ]     = NVME_CMD_EFF_CSUPP,
     [NVME_ADM_CMD_NS_ATTACHMENT]    = NVME_CMD_EFF_CSUPP | NVME_CMD_EFF_NIC,
     [NVME_ADM_CMD_VIRT_MNGMT]       = NVME_CMD_EFF_CSUPP,
+    [NVME_ADM_CMD_DBBUF_CONFIG]     = NVME_CMD_EFF_CSUPP,
     [NVME_ADM_CMD_FORMAT_NVM]       = NVME_CMD_EFF_CSUPP | NVME_CMD_EFF_LBCC,
 };
 
@@ -1330,6 +1331,13 @@
     }
 }
 
+static void nvme_update_cq_head(NvmeCQueue *cq)
+{
+    pci_dma_read(&cq->ctrl->parent_obj, cq->db_addr, &cq->head,
+            sizeof(cq->head));
+    trace_pci_nvme_shadow_doorbell_cq(cq->cqid, cq->head);
+}
+
 static void nvme_post_cqes(void *opaque)
 {
     NvmeCQueue *cq = opaque;
@@ -1342,6 +1350,10 @@
         NvmeSQueue *sq;
         hwaddr addr;
 
+        if (n->dbbuf_enabled) {
+            nvme_update_cq_head(cq);
+        }
+
         if (nvme_cq_full(cq)) {
             break;
         }
@@ -1388,7 +1400,14 @@
 
     QTAILQ_REMOVE(&req->sq->out_req_list, req, entry);
     QTAILQ_INSERT_TAIL(&cq->req_list, req, entry);
-    timer_mod(cq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 500);
+
+    if (req->sq->ioeventfd_enabled) {
+        /* Post CQE directly since we are in main loop thread */
+        nvme_post_cqes(cq);
+    } else {
+        /* Schedule the timer to post CQE later since we are in vcpu thread */
+        timer_mod(cq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 500);
+    }
 }
 
 static void nvme_process_aers(void *opaque)
@@ -4214,10 +4233,82 @@
     return NVME_INVALID_OPCODE | NVME_DNR;
 }
 
+static void nvme_cq_notifier(EventNotifier *e)
+{
+    NvmeCQueue *cq = container_of(e, NvmeCQueue, notifier);
+    NvmeCtrl *n = cq->ctrl;
+
+    event_notifier_test_and_clear(&cq->notifier);
+
+    nvme_update_cq_head(cq);
+
+    if (cq->tail == cq->head) {
+        if (cq->irq_enabled) {
+            n->cq_pending--;
+        }
+
+        nvme_irq_deassert(n, cq);
+    }
+
+    nvme_post_cqes(cq);
+}
+
+static int nvme_init_cq_ioeventfd(NvmeCQueue *cq)
+{
+    NvmeCtrl *n = cq->ctrl;
+    uint16_t offset = (cq->cqid << 3) + (1 << 2);
+    int ret;
+
+    ret = event_notifier_init(&cq->notifier, 0);
+    if (ret < 0) {
+        return ret;
+    }
+
+    event_notifier_set_handler(&cq->notifier, nvme_cq_notifier);
+    memory_region_add_eventfd(&n->iomem,
+                              0x1000 + offset, 4, false, 0, &cq->notifier);
+
+    return 0;
+}
+
+static void nvme_sq_notifier(EventNotifier *e)
+{
+    NvmeSQueue *sq = container_of(e, NvmeSQueue, notifier);
+
+    event_notifier_test_and_clear(&sq->notifier);
+
+    nvme_process_sq(sq);
+}
+
+static int nvme_init_sq_ioeventfd(NvmeSQueue *sq)
+{
+    NvmeCtrl *n = sq->ctrl;
+    uint16_t offset = sq->sqid << 3;
+    int ret;
+
+    ret = event_notifier_init(&sq->notifier, 0);
+    if (ret < 0) {
+        return ret;
+    }
+
+    event_notifier_set_handler(&sq->notifier, nvme_sq_notifier);
+    memory_region_add_eventfd(&n->iomem,
+                              0x1000 + offset, 4, false, 0, &sq->notifier);
+
+    return 0;
+}
+
 static void nvme_free_sq(NvmeSQueue *sq, NvmeCtrl *n)
 {
+    uint16_t offset = sq->sqid << 3;
+
     n->sq[sq->sqid] = NULL;
     timer_free(sq->timer);
+    if (sq->ioeventfd_enabled) {
+        memory_region_del_eventfd(&n->iomem,
+                                  0x1000 + offset, 4, false, 0, &sq->notifier);
+        event_notifier_cleanup(&sq->notifier);
+    }
     g_free(sq->io_req);
     if (sq->sqid) {
         g_free(sq);
@@ -4287,6 +4378,17 @@
     }
     sq->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, nvme_process_sq, sq);
 
+    if (n->dbbuf_enabled) {
+        sq->db_addr = n->dbbuf_dbs + (sqid << 3);
+        sq->ei_addr = n->dbbuf_eis + (sqid << 3);
+
+        if (n->params.ioeventfd && sq->sqid != 0) {
+            if (!nvme_init_sq_ioeventfd(sq)) {
+                sq->ioeventfd_enabled = true;
+            }
+        }
+    }
+
     assert(n->cq[cqid]);
     cq = n->cq[cqid];
     QTAILQ_INSERT_TAIL(&(cq->sq_list), sq, entry);
@@ -4588,8 +4690,15 @@
 
 static void nvme_free_cq(NvmeCQueue *cq, NvmeCtrl *n)
 {
+    uint16_t offset = (cq->cqid << 3) + (1 << 2);
+
     n->cq[cq->cqid] = NULL;
     timer_free(cq->timer);
+    if (cq->ioeventfd_enabled) {
+        memory_region_del_eventfd(&n->iomem,
+                                  0x1000 + offset, 4, false, 0, &cq->notifier);
+        event_notifier_cleanup(&cq->notifier);
+    }
     if (msix_enabled(&n->parent_obj)) {
         msix_vector_unuse(&n->parent_obj, cq->vector);
     }
@@ -4645,6 +4754,16 @@
     cq->head = cq->tail = 0;
     QTAILQ_INIT(&cq->req_list);
     QTAILQ_INIT(&cq->sq_list);
+    if (n->dbbuf_enabled) {
+        cq->db_addr = n->dbbuf_dbs + (cqid << 3) + (1 << 2);
+        cq->ei_addr = n->dbbuf_eis + (cqid << 3) + (1 << 2);
+
+        if (n->params.ioeventfd && cqid != 0) {
+            if (!nvme_init_cq_ioeventfd(cq)) {
+                cq->ioeventfd_enabled = true;
+            }
+        }
+    }
     n->cq[cqid] = cq;
     cq->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, nvme_post_cqes, cq);
 }
@@ -5988,6 +6107,64 @@
     }
 }
 
+static uint16_t nvme_dbbuf_config(NvmeCtrl *n, const NvmeRequest *req)
+{
+    uint64_t dbs_addr = le64_to_cpu(req->cmd.dptr.prp1);
+    uint64_t eis_addr = le64_to_cpu(req->cmd.dptr.prp2);
+    int i;
+
+    /* Address should be page aligned */
+    if (dbs_addr & (n->page_size - 1) || eis_addr & (n->page_size - 1)) {
+        return NVME_INVALID_FIELD | NVME_DNR;
+    }
+
+    /* Save shadow buffer base addr for use during queue creation */
+    n->dbbuf_dbs = dbs_addr;
+    n->dbbuf_eis = eis_addr;
+    n->dbbuf_enabled = true;
+
+    for (i = 0; i < n->params.max_ioqpairs + 1; i++) {
+        NvmeSQueue *sq = n->sq[i];
+        NvmeCQueue *cq = n->cq[i];
+
+        if (sq) {
+            /*
+             * CAP.DSTRD is 0, so offset of ith sq db_addr is (i<<3)
+             * nvme_process_db() uses this hard-coded way to calculate
+             * doorbell offsets. Be consistent with that here.
+             */
+            sq->db_addr = dbs_addr + (i << 3);
+            sq->ei_addr = eis_addr + (i << 3);
+            pci_dma_write(&n->parent_obj, sq->db_addr, &sq->tail,
+                    sizeof(sq->tail));
+
+            if (n->params.ioeventfd && sq->sqid != 0) {
+                if (!nvme_init_sq_ioeventfd(sq)) {
+                    sq->ioeventfd_enabled = true;
+                }
+            }
+        }
+
+        if (cq) {
+            /* CAP.DSTRD is 0, so offset of ith cq db_addr is (i<<3)+(1<<2) */
+            cq->db_addr = dbs_addr + (i << 3) + (1 << 2);
+            cq->ei_addr = eis_addr + (i << 3) + (1 << 2);
+            pci_dma_write(&n->parent_obj, cq->db_addr, &cq->head,
+                    sizeof(cq->head));
+
+            if (n->params.ioeventfd && cq->cqid != 0) {
+                if (!nvme_init_cq_ioeventfd(cq)) {
+                    cq->ioeventfd_enabled = true;
+                }
+            }
+        }
+    }
+
+    trace_pci_nvme_dbbuf_config(dbs_addr, eis_addr);
+
+    return NVME_SUCCESS;
+}
+
 static uint16_t nvme_admin_cmd(NvmeCtrl *n, NvmeRequest *req)
 {
     trace_pci_nvme_admin_cmd(nvme_cid(req), nvme_sqid(req), req->cmd.opcode,
@@ -6032,6 +6209,8 @@
         return nvme_ns_attachment(n, req);
     case NVME_ADM_CMD_VIRT_MNGMT:
         return nvme_virt_mngmt(n, req);
+    case NVME_ADM_CMD_DBBUF_CONFIG:
+        return nvme_dbbuf_config(n, req);
     case NVME_ADM_CMD_FORMAT_NVM:
         return nvme_format(n, req);
     default:
@@ -6041,6 +6220,20 @@
     return NVME_INVALID_OPCODE | NVME_DNR;
 }
 
+static void nvme_update_sq_eventidx(const NvmeSQueue *sq)
+{
+    pci_dma_write(&sq->ctrl->parent_obj, sq->ei_addr, &sq->tail,
+                  sizeof(sq->tail));
+    trace_pci_nvme_eventidx_sq(sq->sqid, sq->tail);
+}
+
+static void nvme_update_sq_tail(NvmeSQueue *sq)
+{
+    pci_dma_read(&sq->ctrl->parent_obj, sq->db_addr, &sq->tail,
+                 sizeof(sq->tail));
+    trace_pci_nvme_shadow_doorbell_sq(sq->sqid, sq->tail);
+}
+
 static void nvme_process_sq(void *opaque)
 {
     NvmeSQueue *sq = opaque;
@@ -6052,6 +6245,10 @@
     NvmeCmd cmd;
     NvmeRequest *req;
 
+    if (n->dbbuf_enabled) {
+        nvme_update_sq_tail(sq);
+    }
+
     while (!(nvme_sq_empty(sq) || QTAILQ_EMPTY(&sq->req_list))) {
         addr = sq->dma_addr + sq->head * n->sqe_size;
         if (nvme_addr_read(n, addr, (void *)&cmd, sizeof(cmd))) {
@@ -6075,6 +6272,11 @@
             req->status = status;
             nvme_enqueue_req_completion(cq, req);
         }
+
+        if (n->dbbuf_enabled) {
+            nvme_update_sq_eventidx(sq);
+            nvme_update_sq_tail(sq);
+        }
     }
 }
 
@@ -6184,6 +6386,10 @@
     stl_le_p(&n->bar.intms, 0);
     stl_le_p(&n->bar.intmc, 0);
     stl_le_p(&n->bar.cc, 0);
+
+    n->dbbuf_dbs = 0;
+    n->dbbuf_eis = 0;
+    n->dbbuf_enabled = false;
 }
 
 static void nvme_ctrl_shutdown(NvmeCtrl *n)
@@ -6694,6 +6900,10 @@
 
         start_sqs = nvme_cq_full(cq) ? 1 : 0;
         cq->head = new_head;
+        if (!qid && n->dbbuf_enabled) {
+            pci_dma_write(&n->parent_obj, cq->db_addr, &cq->head,
+                          sizeof(cq->head));
+        }
         if (start_sqs) {
             NvmeSQueue *sq;
             QTAILQ_FOREACH(sq, &cq->sq_list, entry) {
@@ -6751,6 +6961,23 @@
         trace_pci_nvme_mmio_doorbell_sq(sq->sqid, new_tail);
 
         sq->tail = new_tail;
+        if (!qid && n->dbbuf_enabled) {
+            /*
+             * The spec states "the host shall also update the controller's
+             * corresponding doorbell property to match the value of that entry
+             * in the Shadow Doorbell buffer."
+             *
+             * Since this context is currently a VM trap, we can safely enforce
+             * the requirement from the device side in case the host is
+             * misbehaving.
+             *
+             * Note, we shouldn't have to do this, but various drivers
+             * including ones that run on Linux, are not updating Admin Queues,
+             * so we can't trust reading it for an appropriate sq tail.
+             */
+            pci_dma_write(&n->parent_obj, sq->db_addr, &sq->tail,
+                          sizeof(sq->tail));
+        }
         timer_mod(sq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 500);
     }
 }
@@ -7231,7 +7458,8 @@
 
     id->mdts = n->params.mdts;
     id->ver = cpu_to_le32(NVME_SPEC_VER);
-    id->oacs = cpu_to_le16(NVME_OACS_NS_MGMT | NVME_OACS_FORMAT);
+    id->oacs =
+        cpu_to_le16(NVME_OACS_NS_MGMT | NVME_OACS_FORMAT | NVME_OACS_DBBUF);
     id->cntrltype = 0x1;
 
     /*
@@ -7436,6 +7664,7 @@
     DEFINE_PROP_UINT8("vsl", NvmeCtrl, params.vsl, 7),
     DEFINE_PROP_BOOL("use-intel-id", NvmeCtrl, params.use_intel_id, false),
     DEFINE_PROP_BOOL("legacy-cmb", NvmeCtrl, params.legacy_cmb, false),
+    DEFINE_PROP_BOOL("ioeventfd", NvmeCtrl, params.ioeventfd, true),
     DEFINE_PROP_UINT8("zoned.zasl", NvmeCtrl, params.zasl, 0),
     DEFINE_PROP_BOOL("zoned.auto_transition", NvmeCtrl,
                      params.auto_transition_zones, true),
diff --git a/hw/nvme/ns.c b/hw/nvme/ns.c
index 870c3ca..62a1f97 100644
--- a/hw/nvme/ns.c
+++ b/hw/nvme/ns.c
@@ -546,6 +546,8 @@
     int i;
 
     if (!n->subsys) {
+        /* If no subsys, the ns cannot be attached to more than one ctrl. */
+        ns->params.shared = false;
         if (ns->params.detached) {
             error_setg(errp, "detached requires that the nvme device is "
                        "linked to an nvme-subsys device");
diff --git a/hw/nvme/nvme.h b/hw/nvme/nvme.h
index 99437d3..79f5c28 100644
--- a/hw/nvme/nvme.h
+++ b/hw/nvme/nvme.h
@@ -341,6 +341,7 @@
     case NVME_ADM_CMD_ASYNC_EV_REQ:     return "NVME_ADM_CMD_ASYNC_EV_REQ";
     case NVME_ADM_CMD_NS_ATTACHMENT:    return "NVME_ADM_CMD_NS_ATTACHMENT";
     case NVME_ADM_CMD_VIRT_MNGMT:       return "NVME_ADM_CMD_VIRT_MNGMT";
+    case NVME_ADM_CMD_DBBUF_CONFIG:     return "NVME_ADM_CMD_DBBUF_CONFIG";
     case NVME_ADM_CMD_FORMAT_NVM:       return "NVME_ADM_CMD_FORMAT_NVM";
     default:                            return "NVME_ADM_CMD_UNKNOWN";
     }
@@ -372,7 +373,11 @@
     uint32_t    tail;
     uint32_t    size;
     uint64_t    dma_addr;
+    uint64_t    db_addr;
+    uint64_t    ei_addr;
     QEMUTimer   *timer;
+    EventNotifier notifier;
+    bool        ioeventfd_enabled;
     NvmeRequest *io_req;
     QTAILQ_HEAD(, NvmeRequest) req_list;
     QTAILQ_HEAD(, NvmeRequest) out_req_list;
@@ -389,7 +394,11 @@
     uint32_t    vector;
     uint32_t    size;
     uint64_t    dma_addr;
+    uint64_t    db_addr;
+    uint64_t    ei_addr;
     QEMUTimer   *timer;
+    EventNotifier notifier;
+    bool        ioeventfd_enabled;
     QTAILQ_HEAD(, NvmeSQueue) sq_list;
     QTAILQ_HEAD(, NvmeRequest) req_list;
 } NvmeCQueue;
@@ -412,6 +421,7 @@
     uint8_t  zasl;
     bool     auto_transition_zones;
     bool     legacy_cmb;
+    bool     ioeventfd;
     uint8_t  sriov_max_vfs;
     uint16_t sriov_vq_flexible;
     uint16_t sriov_vi_flexible;
@@ -445,6 +455,9 @@
     uint8_t     smart_critical_warning;
     uint32_t    conf_msix_qsize;
     uint32_t    conf_ioqpairs;
+    uint64_t    dbbuf_dbs;
+    uint64_t    dbbuf_eis;
+    bool        dbbuf_enabled;
 
     struct {
         MemoryRegion mem;
diff --git a/hw/nvme/trace-events b/hw/nvme/trace-events
index 065e1c8..fccb79f 100644
--- a/hw/nvme/trace-events
+++ b/hw/nvme/trace-events
@@ -3,6 +3,7 @@
 pci_nvme_irq_pin(void) "pulsing IRQ pin"
 pci_nvme_irq_masked(void) "IRQ is masked"
 pci_nvme_dma_read(uint64_t prp1, uint64_t prp2) "DMA read, prp1=0x%"PRIx64" prp2=0x%"PRIx64""
+pci_nvme_dbbuf_config(uint64_t dbs_addr, uint64_t eis_addr) "dbs_addr=0x%"PRIx64" eis_addr=0x%"PRIx64""
 pci_nvme_map_addr(uint64_t addr, uint64_t len) "addr 0x%"PRIx64" len %"PRIu64""
 pci_nvme_map_addr_cmb(uint64_t addr, uint64_t len) "addr 0x%"PRIx64" len %"PRIu64""
 pci_nvme_map_prp(uint64_t trans_len, uint32_t len, uint64_t prp1, uint64_t prp2, int num_prps) "trans_len %"PRIu64" len %"PRIu32" prp1 0x%"PRIx64" prp2 0x%"PRIx64" num_prps %d"
@@ -83,6 +84,8 @@
 pci_nvme_enqueue_event_masked(uint8_t typ) "type 0x%"PRIx8""
 pci_nvme_no_outstanding_aers(void) "ignoring event; no outstanding AERs"
 pci_nvme_enqueue_req_completion(uint16_t cid, uint16_t cqid, uint32_t dw0, uint32_t dw1, uint16_t status) "cid %"PRIu16" cqid %"PRIu16" dw0 0x%"PRIx32" dw1 0x%"PRIx32" status 0x%"PRIx16""
+pci_nvme_eventidx_cq(uint16_t cqid, uint16_t new_eventidx) "cqid %"PRIu16" new_eventidx %"PRIu16""
+pci_nvme_eventidx_sq(uint16_t sqid, uint16_t new_eventidx) "sqid %"PRIu16" new_eventidx %"PRIu16""
 pci_nvme_mmio_read(uint64_t addr, unsigned size) "addr 0x%"PRIx64" size %d"
 pci_nvme_mmio_write(uint64_t addr, uint64_t data, unsigned size) "addr 0x%"PRIx64" data 0x%"PRIx64" size %d"
 pci_nvme_mmio_doorbell_cq(uint16_t cqid, uint16_t new_head) "cqid %"PRIu16" new_head %"PRIu16""
@@ -99,6 +102,8 @@
 pci_nvme_mmio_stopped(void) "cleared controller enable bit"
 pci_nvme_mmio_shutdown_set(void) "shutdown bit set"
 pci_nvme_mmio_shutdown_cleared(void) "shutdown bit cleared"
+pci_nvme_shadow_doorbell_cq(uint16_t cqid, uint16_t new_shadow_doorbell) "cqid %"PRIu16" new_shadow_doorbell %"PRIu16""
+pci_nvme_shadow_doorbell_sq(uint16_t sqid, uint16_t new_shadow_doorbell) "sqid %"PRIu16" new_shadow_doorbell %"PRIu16""
 pci_nvme_open_zone(uint64_t slba, uint32_t zone_idx, int all) "open zone, slba=%"PRIu64", idx=%"PRIu32", all=%"PRIi32""
 pci_nvme_close_zone(uint64_t slba, uint32_t zone_idx, int all) "close zone, slba=%"PRIu64", idx=%"PRIu32", all=%"PRIi32""
 pci_nvme_finish_zone(uint64_t slba, uint32_t zone_idx, int all) "finish zone, slba=%"PRIu64", idx=%"PRIu32", all=%"PRIi32""
diff --git a/include/block/nvme.h b/include/block/nvme.h
index 373c70b..8027b71 100644
--- a/include/block/nvme.h
+++ b/include/block/nvme.h
@@ -98,28 +98,28 @@
 #define NVME_CAP_PMRS(cap)  (((cap) >> CAP_PMRS_SHIFT)   & CAP_PMRS_MASK)
 #define NVME_CAP_CMBS(cap)  (((cap) >> CAP_CMBS_SHIFT)   & CAP_CMBS_MASK)
 
-#define NVME_CAP_SET_MQES(cap, val)   (cap |= (uint64_t)(val & CAP_MQES_MASK)  \
-                                                           << CAP_MQES_SHIFT)
-#define NVME_CAP_SET_CQR(cap, val)    (cap |= (uint64_t)(val & CAP_CQR_MASK)   \
-                                                           << CAP_CQR_SHIFT)
-#define NVME_CAP_SET_AMS(cap, val)    (cap |= (uint64_t)(val & CAP_AMS_MASK)   \
-                                                           << CAP_AMS_SHIFT)
-#define NVME_CAP_SET_TO(cap, val)     (cap |= (uint64_t)(val & CAP_TO_MASK)    \
-                                                           << CAP_TO_SHIFT)
-#define NVME_CAP_SET_DSTRD(cap, val)  (cap |= (uint64_t)(val & CAP_DSTRD_MASK) \
-                                                           << CAP_DSTRD_SHIFT)
-#define NVME_CAP_SET_NSSRS(cap, val)  (cap |= (uint64_t)(val & CAP_NSSRS_MASK) \
-                                                           << CAP_NSSRS_SHIFT)
-#define NVME_CAP_SET_CSS(cap, val)    (cap |= (uint64_t)(val & CAP_CSS_MASK)   \
-                                                           << CAP_CSS_SHIFT)
-#define NVME_CAP_SET_MPSMIN(cap, val) (cap |= (uint64_t)(val & CAP_MPSMIN_MASK)\
-                                                           << CAP_MPSMIN_SHIFT)
-#define NVME_CAP_SET_MPSMAX(cap, val) (cap |= (uint64_t)(val & CAP_MPSMAX_MASK)\
-                                                           << CAP_MPSMAX_SHIFT)
-#define NVME_CAP_SET_PMRS(cap, val)   (cap |= (uint64_t)(val & CAP_PMRS_MASK)  \
-                                                           << CAP_PMRS_SHIFT)
-#define NVME_CAP_SET_CMBS(cap, val)   (cap |= (uint64_t)(val & CAP_CMBS_MASK)  \
-                                                           << CAP_CMBS_SHIFT)
+#define NVME_CAP_SET_MQES(cap, val)   \
+    ((cap) |= (uint64_t)((val) & CAP_MQES_MASK)   << CAP_MQES_SHIFT)
+#define NVME_CAP_SET_CQR(cap, val)    \
+    ((cap) |= (uint64_t)((val) & CAP_CQR_MASK)    << CAP_CQR_SHIFT)
+#define NVME_CAP_SET_AMS(cap, val)    \
+    ((cap) |= (uint64_t)((val) & CAP_AMS_MASK)    << CAP_AMS_SHIFT)
+#define NVME_CAP_SET_TO(cap, val)     \
+    ((cap) |= (uint64_t)((val) & CAP_TO_MASK)     << CAP_TO_SHIFT)
+#define NVME_CAP_SET_DSTRD(cap, val)  \
+    ((cap) |= (uint64_t)((val) & CAP_DSTRD_MASK)  << CAP_DSTRD_SHIFT)
+#define NVME_CAP_SET_NSSRS(cap, val)  \
+    ((cap) |= (uint64_t)((val) & CAP_NSSRS_MASK)  << CAP_NSSRS_SHIFT)
+#define NVME_CAP_SET_CSS(cap, val)    \
+    ((cap) |= (uint64_t)((val) & CAP_CSS_MASK)    << CAP_CSS_SHIFT)
+#define NVME_CAP_SET_MPSMIN(cap, val) \
+    ((cap) |= (uint64_t)((val) & CAP_MPSMIN_MASK) << CAP_MPSMIN_SHIFT)
+#define NVME_CAP_SET_MPSMAX(cap, val) \
+    ((cap) |= (uint64_t)((val) & CAP_MPSMAX_MASK) << CAP_MPSMAX_SHIFT)
+#define NVME_CAP_SET_PMRS(cap, val)   \
+    ((cap) |= (uint64_t)((val) & CAP_PMRS_MASK)   << CAP_PMRS_SHIFT)
+#define NVME_CAP_SET_CMBS(cap, val)   \
+    ((cap) |= (uint64_t)((val) & CAP_CMBS_MASK)   << CAP_CMBS_SHIFT)
 
 enum NvmeCapCss {
     NVME_CAP_CSS_NVM        = 1 << 0,
@@ -596,6 +596,7 @@
     NVME_ADM_CMD_DOWNLOAD_FW    = 0x11,
     NVME_ADM_CMD_NS_ATTACHMENT  = 0x15,
     NVME_ADM_CMD_VIRT_MNGMT     = 0x1c,
+    NVME_ADM_CMD_DBBUF_CONFIG   = 0x7c,
     NVME_ADM_CMD_FORMAT_NVM     = 0x80,
     NVME_ADM_CMD_SECURITY_SEND  = 0x81,
     NVME_ADM_CMD_SECURITY_RECV  = 0x82,
@@ -1141,6 +1142,7 @@
     NVME_OACS_FORMAT    = 1 << 1,
     NVME_OACS_FW        = 1 << 2,
     NVME_OACS_NS_MGMT   = 1 << 3,
+    NVME_OACS_DBBUF     = 1 << 8,
 };
 
 enum NvmeIdCtrlOncs {