[PATCH v5 22/26] nvme: support multiple namespaces

[Klaus Jensen <k.jensen@samsung.com>]

This adds support for multiple namespaces by introducing a new 'nvme-ns'
device model. The nvme device creates a bus named from the device name
('id'). The nvme-ns devices then connect to this and registers
themselves with the nvme device.

This changes how an nvme device is created. Example with two namespaces:

  -drive file=nvme0n1.img,if=none,id=disk1
  -drive file=nvme0n2.img,if=none,id=disk2
  -device nvme,serial=deadbeef,id=nvme0
  -device nvme-ns,drive=disk1,bus=nvme0,nsid=1
  -device nvme-ns,drive=disk2,bus=nvme0,nsid=2

The drive property is kept on the nvme device to keep the change
backward compatible, but the property is now optional. Specifying a
drive for the nvme device will always create the namespace with nsid 1.

Signed-off-by: Klaus Jensen <klaus.jensen@cnexlabs.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
---
 hw/block/Makefile.objs |   2 +-
 hw/block/nvme-ns.c     | 158 +++++++++++++++++++++++++++
 hw/block/nvme-ns.h     |  60 +++++++++++
 hw/block/nvme.c        | 235 +++++++++++++++++++++++++----------------
 hw/block/nvme.h        |  47 ++++-----
 hw/block/trace-events  |   6 +-
 6 files changed, 389 insertions(+), 119 deletions(-)
 create mode 100644 hw/block/nvme-ns.c
 create mode 100644 hw/block/nvme-ns.h

diff --git a/hw/block/Makefile.objs b/hw/block/Makefile.objs
index 28c2495a00dc..45f463462f1e 100644
--- a/hw/block/Makefile.objs
+++ b/hw/block/Makefile.objs
@@ -7,7 +7,7 @@ common-obj-$(CONFIG_PFLASH_CFI02) += pflash_cfi02.o
 common-obj-$(CONFIG_XEN) += xen-block.o
 common-obj-$(CONFIG_ECC) += ecc.o
 common-obj-$(CONFIG_ONENAND) += onenand.o
-common-obj-$(CONFIG_NVME_PCI) += nvme.o
+common-obj-$(CONFIG_NVME_PCI) += nvme.o nvme-ns.o
 common-obj-$(CONFIG_SWIM) += swim.o
 
 obj-$(CONFIG_SH4) += tc58128.o
diff --git a/hw/block/nvme-ns.c b/hw/block/nvme-ns.c
new file mode 100644
index 000000000000..0e5be44486f4
--- /dev/null
+++ b/hw/block/nvme-ns.c
@@ -0,0 +1,158 @@
+#include "qemu/osdep.h"
+#include "qemu/units.h"
+#include "qemu/cutils.h"
+#include "qemu/log.h"
+#include "hw/block/block.h"
+#include "hw/pci/msix.h"
+#include "sysemu/sysemu.h"
+#include "sysemu/block-backend.h"
+#include "qapi/error.h"
+
+#include "hw/qdev-properties.h"
+#include "hw/qdev-core.h"
+
+#include "nvme.h"
+#include "nvme-ns.h"
+
+static int nvme_ns_init(NvmeNamespace *ns)
+{
+    NvmeIdNs *id_ns = &ns->id_ns;
+
+    id_ns->lbaf[0].ds = BDRV_SECTOR_BITS;
+    id_ns->nuse = id_ns->ncap = id_ns->nsze =
+        cpu_to_le64(nvme_ns_nlbas(ns));
+
+    return 0;
+}
+
+static int nvme_ns_init_blk(NvmeCtrl *n, NvmeNamespace *ns, NvmeIdCtrl *id,
+    Error **errp)
+{
+    uint64_t perm, shared_perm;
+
+    Error *local_err = NULL;
+    int ret;
+
+    perm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE;
+    shared_perm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
+        BLK_PERM_GRAPH_MOD;
+
+    ret = blk_set_perm(ns->blk, perm, shared_perm, &local_err);
+    if (ret) {
+        error_propagate_prepend(errp, local_err, "blk_set_perm: ");
+        return ret;
+    }
+
+    ns->size = blk_getlength(ns->blk);
+    if (ns->size < 0) {
+        error_setg_errno(errp, -ns->size, "blk_getlength");
+        return 1;
+    }
+
+    switch (n->conf.wce) {
+    case ON_OFF_AUTO_ON:
+        n->features.volatile_wc = 1;
+        break;
+    case ON_OFF_AUTO_OFF:
+        n->features.volatile_wc = 0;
+    case ON_OFF_AUTO_AUTO:
+        n->features.volatile_wc = blk_enable_write_cache(ns->blk);
+        break;
+    default:
+        abort();
+    }
+
+    blk_set_enable_write_cache(ns->blk, n->features.volatile_wc);
+
+    return 0;
+}
+
+static int nvme_ns_check_constraints(NvmeNamespace *ns, Error **errp)
+{
+    if (!ns->blk) {
+        error_setg(errp, "block backend not configured");
+        return 1;
+    }
+
+    return 0;
+}
+
+int nvme_ns_setup(NvmeCtrl *n, NvmeNamespace *ns, Error **errp)
+{
+    Error *local_err = NULL;
+
+    if (nvme_ns_check_constraints(ns, &local_err)) {
+        error_propagate_prepend(errp, local_err,
+            "nvme_ns_check_constraints: ");
+        return 1;
+    }
+
+    if (nvme_ns_init_blk(n, ns, &n->id_ctrl, &local_err)) {
+        error_propagate_prepend(errp, local_err, "nvme_ns_init_blk: ");
+        return 1;
+    }
+
+    nvme_ns_init(ns);
+    if (nvme_register_namespace(n, ns, &local_err)) {
+        error_propagate_prepend(errp, local_err, "nvme_register_namespace: ");
+        return 1;
+    }
+
+    return 0;
+}
+
+static void nvme_ns_realize(DeviceState *dev, Error **errp)
+{
+    NvmeNamespace *ns = NVME_NS(dev);
+    BusState *s = qdev_get_parent_bus(dev);
+    NvmeCtrl *n = NVME(s->parent);
+    Error *local_err = NULL;
+
+    if (nvme_ns_setup(n, ns, &local_err)) {
+        error_propagate_prepend(errp, local_err, "nvme_ns_setup: ");
+        return;
+    }
+}
+
+static Property nvme_ns_props[] = {
+    DEFINE_NVME_NS_PROPERTIES(NvmeNamespace, params),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void nvme_ns_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
+
+    dc->bus_type = TYPE_NVME_BUS;
+    dc->realize = nvme_ns_realize;
+    device_class_set_props(dc, nvme_ns_props);
+    dc->desc = "virtual nvme namespace";
+}
+
+static void nvme_ns_instance_init(Object *obj)
+{
+    NvmeNamespace *ns = NVME_NS(obj);
+    char *bootindex = g_strdup_printf("/namespace@%d,0", ns->params.nsid);
+
+    device_add_bootindex_property(obj, &ns->bootindex, "bootindex",
+        bootindex, DEVICE(obj), &error_abort);
+
+    g_free(bootindex);
+}
+
+static const TypeInfo nvme_ns_info = {
+    .name = TYPE_NVME_NS,
+    .parent = TYPE_DEVICE,
+    .class_init = nvme_ns_class_init,
+    .instance_size = sizeof(NvmeNamespace),
+    .instance_init = nvme_ns_instance_init,
+};
+
+static void nvme_ns_register_types(void)
+{
+    type_register_static(&nvme_ns_info);
+}
+
+type_init(nvme_ns_register_types)
diff --git a/hw/block/nvme-ns.h b/hw/block/nvme-ns.h
new file mode 100644
index 000000000000..b564bac25f6d
--- /dev/null
+++ b/hw/block/nvme-ns.h
@@ -0,0 +1,60 @@
+#ifndef NVME_NS_H
+#define NVME_NS_H
+
+#define TYPE_NVME_NS "nvme-ns"
+#define NVME_NS(obj) \
+    OBJECT_CHECK(NvmeNamespace, (obj), TYPE_NVME_NS)
+
+#define DEFINE_NVME_NS_PROPERTIES(_state, _props) \
+    DEFINE_PROP_DRIVE("drive", _state, blk), \
+    DEFINE_PROP_UINT32("nsid", _state, _props.nsid, 0)
+
+typedef struct NvmeNamespaceParams {
+    uint32_t nsid;
+} NvmeNamespaceParams;
+
+typedef struct NvmeNamespace {
+    DeviceState  parent_obj;
+    BlockBackend *blk;
+    int32_t      bootindex;
+    int64_t      size;
+
+    NvmeIdNs            id_ns;
+    NvmeNamespaceParams params;
+} NvmeNamespace;
+
+static inline uint32_t nvme_nsid(NvmeNamespace *ns)
+{
+    if (ns) {
+        return ns->params.nsid;
+    }
+
+    return -1;
+}
+
+static inline NvmeLBAF nvme_ns_lbaf(NvmeNamespace *ns)
+{
+    NvmeIdNs *id_ns = &ns->id_ns;
+    return id_ns->lbaf[NVME_ID_NS_FLBAS_INDEX(id_ns->flbas)];
+}
+
+static inline uint8_t nvme_ns_lbads(NvmeNamespace *ns)
+{
+    return nvme_ns_lbaf(ns).ds;
+}
+
+static inline size_t nvme_ns_lbads_bytes(NvmeNamespace *ns)
+{
+    return 1 << nvme_ns_lbads(ns);
+}
+
+static inline uint64_t nvme_ns_nlbas(NvmeNamespace *ns)
+{
+    return ns->size >> nvme_ns_lbads(ns);
+}
+
+typedef struct NvmeCtrl NvmeCtrl;
+
+int nvme_ns_setup(NvmeCtrl *n, NvmeNamespace *ns, Error **errp);
+
+#endif /* NVME_NS_H */
diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index a91c60fdc111..3a377bc56734 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -17,10 +17,11 @@
 /**
  * Usage: add options:
  *      -drive file=<file>,if=none,id=<drive_id>
- *      -device nvme,drive=<drive_id>,serial=<serial>,id=<id[optional]>, \
+ *      -device nvme,serial=<serial>,id=<bus_name>, \
  *              cmb_size_mb=<cmb_size_mb[optional]>, \
  *              num_queues=<N[optional]>, \
  *              mdts=<mdts[optional]>
+ *      -device nvme-ns,drive=<drive_id>,bus=bus_name,nsid=1
  *
  * Note cmb_size_mb denotes size of CMB in MB. CMB is assumed to be at
  * offset 0 in BAR2 and supports only WDS, RDS and SQS for now.
@@ -28,6 +29,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/units.h"
+#include "qemu/error-report.h"
 #include "hw/block/block.h"
 #include "hw/pci/msix.h"
 #include "hw/pci/pci.h"
@@ -43,6 +45,7 @@
 #include "qemu/cutils.h"
 #include "trace.h"
 #include "nvme.h"
+#include "nvme-ns.h"
 
 #define NVME_SPEC_VER 0x00010300
 #define NVME_MAX_QS PCI_MSIX_FLAGS_QSIZE
@@ -85,6 +88,17 @@ static int nvme_addr_read(NvmeCtrl *n, hwaddr addr, void *buf, int size)
     return pci_dma_read(&n->parent_obj, addr, buf, size);
 }
 
+static uint16_t nvme_nsid_err(NvmeCtrl *n, uint32_t nsid)
+{
+    if (nsid && nsid < n->num_namespaces) {
+        trace_nvme_dev_err_inactive_ns(nsid, n->num_namespaces);
+        return NVME_INVALID_FIELD | NVME_DNR;
+    }
+
+    trace_nvme_dev_err_invalid_ns(nsid, n->num_namespaces);
+    return NVME_INVALID_NSID | NVME_DNR;
+}
+
 static int nvme_check_sqid(NvmeCtrl *n, uint16_t sqid)
 {
     return sqid < n->params.num_queues && n->sq[sqid] != NULL ? 0 : -1;
@@ -889,7 +903,7 @@ static inline uint16_t nvme_check_bounds(NvmeCtrl *n, uint64_t slba,
     uint64_t nsze = le64_to_cpu(ns->id_ns.nsze);
 
     if (unlikely((slba + nlb) > nsze)) {
-        block_acct_invalid(blk_get_stats(n->conf.blk),
+        block_acct_invalid(blk_get_stats(ns->blk),
             nvme_req_is_write(req) ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
         trace_nvme_dev_err_invalid_lba_range(slba, nlb, nsze);
         return NVME_LBA_RANGE | NVME_DNR;
@@ -924,11 +938,12 @@ static uint16_t nvme_check_rw(NvmeCtrl *n, NvmeRequest *req)
 
 static void nvme_rw_cb(NvmeRequest *req, void *opaque)
 {
+    NvmeNamespace *ns = req->ns;
     NvmeSQueue *sq = req->sq;
     NvmeCtrl *n = sq->ctrl;
     NvmeCQueue *cq = n->cq[sq->cqid];
 
-    trace_nvme_dev_rw_cb(nvme_cid(req), req->cmd.nsid);
+    trace_nvme_dev_rw_cb(nvme_cid(req), nvme_nsid(ns));
 
     nvme_enqueue_req_completion(cq, req);
 }
@@ -1011,10 +1026,11 @@ static void nvme_aio_cb(void *opaque, int ret)
 
 static uint16_t nvme_flush(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
 {
+    NvmeNamespace *ns = req->ns;
     NvmeAIO *aio = g_new0(NvmeAIO, 1);
 
     *aio = (NvmeAIO) {
-        .blk = n->conf.blk,
+        .blk = ns->blk,
         .req = req,
     };
 
@@ -1038,12 +1054,12 @@ static uint16_t nvme_write_zeros(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
     req->slba = le64_to_cpu(rw->slba);
     req->nlb  = le16_to_cpu(rw->nlb) + 1;
 
-    trace_nvme_dev_write_zeros(nvme_cid(req), le32_to_cpu(cmd->nsid),
-        req->slba, req->nlb);
+    trace_nvme_dev_write_zeros(nvme_cid(req), nvme_nsid(ns), req->slba,
+        req->nlb);
 
     status = nvme_check_bounds(n, req->slba, req->nlb, req);
     if (unlikely(status)) {
-        block_acct_invalid(blk_get_stats(n->conf.blk), BLOCK_ACCT_WRITE);
+        block_acct_invalid(blk_get_stats(ns->blk), BLOCK_ACCT_WRITE);
         return status;
     }
 
@@ -1053,7 +1069,7 @@ static uint16_t nvme_write_zeros(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
     aio = g_new0(NvmeAIO, 1);
 
     *aio = (NvmeAIO) {
-        .blk = n->conf.blk,
+        .blk = ns->blk,
         .offset = offset,
         .len = count,
         .req = req,
@@ -1077,22 +1093,23 @@ static uint16_t nvme_rw(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
     req->nlb  = le16_to_cpu(rw->nlb) + 1;
     req->slba = le64_to_cpu(rw->slba);
 
-    trace_nvme_dev_rw(nvme_req_is_write(req) ? "write" : "read", req->nlb,
-        req->nlb << nvme_ns_lbads(req->ns), req->slba);
+    trace_nvme_dev_rw(nvme_cid(req), nvme_req_is_write(req) ? "write" : "read",
+        nvme_nsid(ns), req->nlb, req->nlb << nvme_ns_lbads(ns),
+        req->slba);
 
     status = nvme_check_rw(n, req);
     if (status) {
-        block_acct_invalid(blk_get_stats(n->conf.blk), acct);
+        block_acct_invalid(blk_get_stats(ns->blk), acct);
         return status;
     }
 
     status = nvme_map(n, cmd, req);
     if (status) {
-        block_acct_invalid(blk_get_stats(n->conf.blk), acct);
+        block_acct_invalid(blk_get_stats(ns->blk), acct);
         return status;
     }
 
-    nvme_rw_aio(n->conf.blk, req->slba << nvme_ns_lbads(ns), req);
+    nvme_rw_aio(ns->blk, req->slba << nvme_ns_lbads(ns), req);
     nvme_req_set_cb(req, nvme_rw_cb, NULL);
 
     return NVME_NO_COMPLETE;
@@ -1105,12 +1122,11 @@ static uint16_t nvme_io_cmd(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
     trace_nvme_dev_io_cmd(nvme_cid(req), nsid, le16_to_cpu(req->sq->sqid),
         cmd->opcode);
 
-    if (unlikely(nsid == 0 || nsid > n->num_namespaces)) {
-        trace_nvme_dev_err_invalid_ns(nsid, n->num_namespaces);
-        return NVME_INVALID_NSID | NVME_DNR;
-    }
+    req->ns = nvme_ns(n, nsid);
 
-    req->ns = &n->namespaces[nsid - 1];
+    if (unlikely(!req->ns)) {
+        return nvme_nsid_err(n, nsid);
+    }
 
     switch (cmd->opcode) {
     case NVME_CMD_FLUSH:
@@ -1256,18 +1272,24 @@ static uint16_t nvme_smart_info(NvmeCtrl *n, NvmeCmd *cmd, uint8_t rae,
     uint64_t units_read = 0, units_written = 0, read_commands = 0,
         write_commands = 0;
     NvmeSmartLog smart;
-    BlockAcctStats *s;
 
     if (nsid && nsid != 0xffffffff) {
         return NVME_INVALID_FIELD | NVME_DNR;
     }
 
-    s = blk_get_stats(n->conf.blk);
+    for (int i = 1; i <= n->num_namespaces; i++) {
+        NvmeNamespace *ns = nvme_ns(n, i);
+        if (!ns) {
+            continue;
+        }
 
-    units_read = s->nr_bytes[BLOCK_ACCT_READ] >> BDRV_SECTOR_BITS;
-    units_written = s->nr_bytes[BLOCK_ACCT_WRITE] >> BDRV_SECTOR_BITS;
-    read_commands = s->nr_ops[BLOCK_ACCT_READ];
-    write_commands = s->nr_ops[BLOCK_ACCT_WRITE];
+        BlockAcctStats *s = blk_get_stats(ns->blk);
+
+        units_read += s->nr_bytes[BLOCK_ACCT_READ] >> BDRV_SECTOR_BITS;
+        units_written += s->nr_bytes[BLOCK_ACCT_WRITE] >> BDRV_SECTOR_BITS;
+        read_commands += s->nr_ops[BLOCK_ACCT_READ];
+        write_commands += s->nr_ops[BLOCK_ACCT_WRITE];
+    }
 
     if (off > sizeof(smart)) {
         return NVME_INVALID_FIELD | NVME_DNR;
@@ -1477,19 +1499,25 @@ static uint16_t nvme_identify_ctrl(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
 
 static uint16_t nvme_identify_ns(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
 {
-    NvmeNamespace *ns;
+    NvmeIdNs *id_ns, inactive = { 0 };
     uint32_t nsid = le32_to_cpu(cmd->nsid);
+    NvmeNamespace *ns = nvme_ns(n, nsid);
 
     trace_nvme_dev_identify_ns(nsid);
 
-    if (unlikely(nsid == 0 || nsid > n->num_namespaces)) {
-        trace_nvme_dev_err_invalid_ns(nsid, n->num_namespaces);
-        return NVME_INVALID_NSID | NVME_DNR;
+    if (unlikely(!ns)) {
+        uint16_t status = nvme_nsid_err(n, nsid);
+
+        if (!nvme_status_is_error(status, NVME_INVALID_FIELD)) {
+            return status;
+        }
+
+        id_ns = &inactive;
+    } else {
+        id_ns = &ns->id_ns;
     }
 
-    ns = &n->namespaces[nsid - 1];
-
-    return nvme_dma(n, (uint8_t *) &ns->id_ns, sizeof(ns->id_ns), cmd,
+    return nvme_dma(n, (uint8_t *) id_ns, sizeof(NvmeIdNs), cmd,
         DMA_DIRECTION_FROM_DEVICE, req);
 }
 
@@ -1505,11 +1533,11 @@ static uint16_t nvme_identify_ns_list(NvmeCtrl *n, NvmeCmd *cmd,
     trace_nvme_dev_identify_ns_list(min_nsid);
 
     list = g_malloc0(data_len);
-    for (i = 0; i < n->num_namespaces; i++) {
-        if (i < min_nsid) {
+    for (i = 1; i <= n->num_namespaces; i++) {
+        if (i <= min_nsid || !nvme_ns(n, i)) {
             continue;
         }
-        list[j++] = cpu_to_le32(i + 1);
+        list[j++] = cpu_to_le32(i);
         if (j == data_len / sizeof(uint32_t)) {
             break;
         }
@@ -1539,9 +1567,8 @@ static uint16_t nvme_identify_ns_descr_list(NvmeCtrl *n, NvmeCmd *cmd,
 
     trace_nvme_dev_identify_ns_descr_list(nsid);
 
-    if (unlikely(nsid == 0 || nsid > n->num_namespaces)) {
-        trace_nvme_dev_err_invalid_ns(nsid, n->num_namespaces);
-        return NVME_INVALID_NSID | NVME_DNR;
+    if (unlikely(!nvme_ns(n, nsid))) {
+        return nvme_nsid_err(n, nsid);
     }
 
     /*
@@ -1681,7 +1708,7 @@ static uint16_t nvme_get_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
         result = cpu_to_le32(n->features.err_rec);
         break;
     case NVME_VOLATILE_WRITE_CACHE:
-        result = blk_enable_write_cache(n->conf.blk);
+        result = cpu_to_le32(n->features.volatile_wc);
         trace_nvme_dev_getfeat_vwcache(result ? "enabled" : "disabled");
         break;
     case NVME_NUMBER_OF_QUEUES:
@@ -1735,6 +1762,8 @@ static uint16_t nvme_set_feature_timestamp(NvmeCtrl *n, NvmeCmd *cmd,
 
 static uint16_t nvme_set_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
 {
+    NvmeNamespace *ns;
+
     uint32_t dw10 = le32_to_cpu(cmd->cdw10);
     uint32_t dw11 = le32_to_cpu(cmd->cdw11);
 
@@ -1766,8 +1795,19 @@ static uint16_t nvme_set_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
 
         break;
     case NVME_VOLATILE_WRITE_CACHE:
-        blk_set_enable_write_cache(n->conf.blk, dw11 & 1);
+        n->features.volatile_wc = dw11;
+
+        for (int i = 1; i <= n->num_namespaces; i++) {
+            ns = nvme_ns(n, i);
+            if (!ns) {
+                continue;
+            }
+
+            blk_set_enable_write_cache(ns->blk, dw11 & 1);
+        }
+
         break;
+
     case NVME_NUMBER_OF_QUEUES:
         if (n->qs_created) {
             return NVME_CMD_SEQ_ERROR | NVME_DNR;
@@ -1890,9 +1930,17 @@ static void nvme_process_sq(void *opaque)
 
 static void nvme_clear_ctrl(NvmeCtrl *n)
 {
+    NvmeNamespace *ns;
     int i;
 
-    blk_drain(n->conf.blk);
+    for (i = 1; i <= n->num_namespaces; i++) {
+        ns = nvme_ns(n, i);
+        if (!ns) {
+            continue;
+        }
+
+        blk_drain(ns->blk);
+    }
 
     for (i = 0; i < n->params.num_queues; i++) {
         if (n->sq[i] != NULL) {
@@ -1915,7 +1963,15 @@ static void nvme_clear_ctrl(NvmeCtrl *n)
     n->outstanding_aers = 0;
     n->qs_created = false;
 
-    blk_flush(n->conf.blk);
+    for (i = 1; i <= n->num_namespaces; i++) {
+        ns = nvme_ns(n, i);
+        if (!ns) {
+            continue;
+        }
+
+        blk_flush(ns->blk);
+    }
+
     n->bar.cc = 0;
 }
 
@@ -2335,8 +2391,8 @@ static int nvme_check_constraints(NvmeCtrl *n, Error **errp)
 {
     NvmeParams *params = &n->params;
 
-    if (!n->conf.blk) {
-        error_setg(errp, "nvme: block backend not configured");
+    if (!n->namespace.blk && !n->parent_obj.qdev.id) {
+        error_setg(errp, "nvme: invalid 'id' parameter");
         return 1;
     }
 
@@ -2353,22 +2409,10 @@ static int nvme_check_constraints(NvmeCtrl *n, Error **errp)
     return 0;
 }
 
-static int nvme_init_blk(NvmeCtrl *n, Error **errp)
-{
-    blkconf_blocksizes(&n->conf);
-    if (!blkconf_apply_backend_options(&n->conf, blk_is_read_only(n->conf.blk),
-        false, errp)) {
-        return 1;
-    }
-
-    return 0;
-}
-
 static void nvme_init_state(NvmeCtrl *n)
 {
-    n->num_namespaces = 1;
+    n->num_namespaces = 0;
     n->reg_size = pow2ceil(0x1004 + 2 * (n->params.num_queues + 1) * 4);
-    n->namespaces = g_new0(NvmeNamespace, n->num_namespaces);
     n->sq = g_new0(NvmeSQueue *, n->params.num_queues);
     n->cq = g_new0(NvmeCQueue *, n->params.num_queues);
 
@@ -2483,12 +2527,7 @@ static void nvme_init_ctrl(NvmeCtrl *n)
     id->cqes = (0x4 << 4) | 0x4;
     id->nn = cpu_to_le32(n->num_namespaces);
     id->oncs = cpu_to_le16(NVME_ONCS_WRITE_ZEROS | NVME_ONCS_TIMESTAMP);
-
-
-    if (blk_enable_write_cache(n->conf.blk)) {
-        id->vwc = 1;
-    }
-
+    id->vwc = 1;
     id->sgls = cpu_to_le32(0x1);
 
     strcpy((char *) id->subnqn, "nqn.2019-08.org.qemu:");
@@ -2509,22 +2548,25 @@ static void nvme_init_ctrl(NvmeCtrl *n)
     n->bar.intmc = n->bar.intms = 0;
 }
 
-static int nvme_init_namespace(NvmeCtrl *n, NvmeNamespace *ns, Error **errp)
+int nvme_register_namespace(NvmeCtrl *n, NvmeNamespace *ns, Error **errp)
 {
-    int64_t bs_size;
-    NvmeIdNs *id_ns = &ns->id_ns;
+    uint32_t nsid = nvme_nsid(ns);
 
-    bs_size = blk_getlength(n->conf.blk);
-    if (bs_size < 0) {
-        error_setg_errno(errp, -bs_size, "blk_getlength");
+    if (nsid == 0 || nsid > NVME_MAX_NAMESPACES) {
+        error_setg(errp, "invalid nsid");
         return 1;
     }
 
-    id_ns->lbaf[0].ds = BDRV_SECTOR_BITS;
-    n->ns_size = bs_size;
+    if (n->namespaces[nsid - 1]) {
+        error_setg(errp, "nsid must be unique");
+        return 1;
+    }
+
+    trace_nvme_dev_register_namespace(nsid);
 
-    id_ns->ncap = id_ns->nuse = id_ns->nsze =
-        cpu_to_le64(nvme_ns_nlbas(n, ns));
+    n->namespaces[nsid - 1] = ns;
+    n->num_namespaces = MAX(n->num_namespaces, nsid);
+    n->id_ctrl.nn = cpu_to_le32(n->num_namespaces);
 
     return 0;
 }
@@ -2532,30 +2574,31 @@ static int nvme_init_namespace(NvmeCtrl *n, NvmeNamespace *ns, Error **errp)
 static void nvme_realize(PCIDevice *pci_dev, Error **errp)
 {
     NvmeCtrl *n = NVME(pci_dev);
+    NvmeNamespace *ns;
     Error *local_err = NULL;
-    int i;
 
     if (nvme_check_constraints(n, &local_err)) {
         error_propagate_prepend(errp, local_err, "nvme_check_constraints: ");
         return;
     }
 
+    qbus_create_inplace(&n->bus, sizeof(NvmeBus), TYPE_NVME_BUS,
+        &pci_dev->qdev, n->parent_obj.qdev.id);
+
     nvme_init_state(n);
-
-    if (nvme_init_blk(n, &local_err)) {
-        error_propagate_prepend(errp, local_err, "nvme_init_blk: ");
-        return;
-    }
-
-    for (i = 0; i < n->num_namespaces; i++) {
-        if (nvme_init_namespace(n, &n->namespaces[i], &local_err)) {
-            error_propagate_prepend(errp, local_err, "nvme_init_namespace: ");
-            return;
-        }
-    }
-
     nvme_init_pci(n, pci_dev);
     nvme_init_ctrl(n);
+
+    /* setup a namespace if the controller drive property was given */
+    if (n->namespace.blk) {
+        ns = &n->namespace;
+        ns->params.nsid = 1;
+
+        if (nvme_ns_setup(n, ns, &local_err)) {
+            error_propagate_prepend(errp, local_err, "nvme_ns_setup: ");
+            return;
+        }
+    }
 }
 
 static void nvme_exit(PCIDevice *pci_dev)
@@ -2576,7 +2619,8 @@ static void nvme_exit(PCIDevice *pci_dev)
 }
 
 static Property nvme_props[] = {
-    DEFINE_BLOCK_PROPERTIES(NvmeCtrl, conf),
+    DEFINE_BLOCK_PROPERTIES_BASE(NvmeCtrl, conf), \
+    DEFINE_PROP_DRIVE("drive", NvmeCtrl, namespace.blk), \
     DEFINE_NVME_PROPERTIES(NvmeCtrl, params),
     DEFINE_PROP_END_OF_LIST(),
 };
@@ -2608,26 +2652,35 @@ static void nvme_instance_init(Object *obj)
 {
     NvmeCtrl *s = NVME(obj);
 
-    device_add_bootindex_property(obj, &s->conf.bootindex,
-                                  "bootindex", "/namespace@1,0",
-                                  DEVICE(obj), &error_abort);
+    if (s->namespace.blk) {
+        device_add_bootindex_property(obj, &s->conf.bootindex,
+                                      "bootindex", "/namespace@1,0",
+                                      DEVICE(obj), &error_abort);
+    }
 }
 
 static const TypeInfo nvme_info = {
     .name          = TYPE_NVME,
     .parent        = TYPE_PCI_DEVICE,
     .instance_size = sizeof(NvmeCtrl),
-    .class_init    = nvme_class_init,
     .instance_init = nvme_instance_init,
+    .class_init    = nvme_class_init,
     .interfaces = (InterfaceInfo[]) {
         { INTERFACE_PCIE_DEVICE },
         { }
     },
 };
 
+static const TypeInfo nvme_bus_info = {
+    .name = TYPE_NVME_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(NvmeBus),
+};
+
 static void nvme_register_types(void)
 {
     type_register_static(&nvme_info);
+    type_register_static(&nvme_bus_info);
 }
 
 type_init(nvme_register_types)
diff --git a/hw/block/nvme.h b/hw/block/nvme.h
index 3319f8edd7e1..c3cef0f024da 100644
--- a/hw/block/nvme.h
+++ b/hw/block/nvme.h
@@ -2,6 +2,9 @@
 #define HW_NVME_H
 
 #include "block/nvme.h"
+#include "nvme-ns.h"
+
+#define NVME_MAX_NAMESPACES 256
 
 #define DEFINE_NVME_PROPERTIES(_state, _props) \
     DEFINE_PROP_STRING("serial", _state, _props.serial), \
@@ -108,26 +111,6 @@ typedef struct NvmeCQueue {
     QTAILQ_HEAD(, NvmeRequest) req_list;
 } NvmeCQueue;
 
-typedef struct NvmeNamespace {
-    NvmeIdNs        id_ns;
-} NvmeNamespace;
-
-static inline NvmeLBAF nvme_ns_lbaf(NvmeNamespace *ns)
-{
-    NvmeIdNs *id_ns = &ns->id_ns;
-    return id_ns->lbaf[NVME_ID_NS_FLBAS_INDEX(id_ns->flbas)];
-}
-
-static inline uint8_t nvme_ns_lbads(NvmeNamespace *ns)
-{
-    return nvme_ns_lbaf(ns).ds;
-}
-
-static inline size_t nvme_ns_lbads_bytes(NvmeNamespace *ns)
-{
-    return 1 << nvme_ns_lbads(ns);
-}
-
 typedef enum NvmeAIOOp {
     NVME_AIO_OPC_NONE         = 0x0,
     NVME_AIO_OPC_FLUSH        = 0x1,
@@ -182,6 +165,13 @@ static inline bool nvme_req_is_write(NvmeRequest *req)
     }
 }
 
+#define TYPE_NVME_BUS "nvme-bus"
+#define NVME_BUS(obj) OBJECT_CHECK(NvmeBus, (obj), TYPE_NVME_BUS)
+
+typedef struct NvmeBus {
+    BusState parent_bus;
+} NvmeBus;
+
 #define TYPE_NVME "nvme"
 #define NVME(obj) \
         OBJECT_CHECK(NvmeCtrl, (obj), TYPE_NVME)
@@ -191,8 +181,9 @@ typedef struct NvmeCtrl {
     MemoryRegion iomem;
     MemoryRegion ctrl_mem;
     NvmeBar      bar;
-    BlockConf    conf;
     NvmeParams   params;
+    NvmeBus      bus;
+    BlockConf    conf;
 
     bool        qs_created;
     uint32_t    page_size;
@@ -203,7 +194,6 @@ typedef struct NvmeCtrl {
     uint32_t    reg_size;
     uint32_t    num_namespaces;
     uint32_t    max_q_ents;
-    uint64_t    ns_size;
     uint8_t     outstanding_aers;
     uint32_t    cmbsz;
     uint32_t    cmbloc;
@@ -219,7 +209,8 @@ typedef struct NvmeCtrl {
     QTAILQ_HEAD(, NvmeAsyncEvent) aer_queue;
     int         aer_queued;
 
-    NvmeNamespace   *namespaces;
+    NvmeNamespace   namespace;
+    NvmeNamespace   *namespaces[NVME_MAX_NAMESPACES];
     NvmeSQueue      **sq;
     NvmeCQueue      **cq;
     NvmeSQueue      admin_sq;
@@ -228,9 +219,13 @@ typedef struct NvmeCtrl {
     NvmeFeatureVal  features;
 } NvmeCtrl;
 
-static inline uint64_t nvme_ns_nlbas(NvmeCtrl *n, NvmeNamespace *ns)
+static inline NvmeNamespace *nvme_ns(NvmeCtrl *n, uint32_t nsid)
 {
-    return n->ns_size >> nvme_ns_lbads(ns);
+    if (!nsid || nsid > n->num_namespaces) {
+        return NULL;
+    }
+
+    return n->namespaces[nsid - 1];
 }
 
 static inline uint16_t nvme_cid(NvmeRequest *req)
@@ -253,4 +248,6 @@ static inline NvmeCtrl *nvme_ctrl(NvmeRequest *req)
     return req->sq->ctrl;
 }
 
+int nvme_register_namespace(NvmeCtrl *n, NvmeNamespace *ns, Error **errp);
+
 #endif /* HW_NVME_H */
diff --git a/hw/block/trace-events b/hw/block/trace-events
index 81d69e15fc32..aaf1fcda7923 100644
--- a/hw/block/trace-events
+++ b/hw/block/trace-events
@@ -29,6 +29,7 @@ hd_geometry_guess(void *blk, uint32_t cyls, uint32_t heads, uint32_t secs, int t
 
 # nvme.c
 # nvme traces for successful events
+nvme_dev_register_namespace(uint32_t nsid) "nsid %"PRIu32""
 nvme_dev_irq_msix(uint32_t vector) "raising MSI-X IRQ vector %u"
 nvme_dev_irq_pin(void) "pulsing IRQ pin"
 nvme_dev_irq_masked(void) "IRQ is masked"
@@ -38,7 +39,7 @@ nvme_dev_map_sgl(uint16_t cid, uint8_t typ, uint32_t nlb, uint64_t len) "cid %"P
 nvme_dev_req_register_aio(uint16_t cid, void *aio, const char *blkname, uint64_t offset, uint64_t count, const char *opc, void *req) "cid %"PRIu16" aio %p blk \"%s\" offset %"PRIu64" count %"PRIu64" opc \"%s\" req %p"
 nvme_dev_aio_cb(uint16_t cid, void *aio, const char *blkname, uint64_t offset, const char *opc, void *req) "cid %"PRIu16" aio %p blk \"%s\" offset %"PRIu64" opc \"%s\" req %p"
 nvme_dev_io_cmd(uint16_t cid, uint32_t nsid, uint16_t sqid, uint8_t opcode) "cid %"PRIu16" nsid %"PRIu32" sqid %"PRIu16" opc 0x%"PRIx8""
-nvme_dev_rw(const char *verb, uint32_t blk_count, uint64_t byte_count, uint64_t lba) "%s %"PRIu32" blocks (%"PRIu64" bytes) from LBA %"PRIu64""
+nvme_dev_rw(uint16_t cid, const char *verb, uint32_t nsid, uint32_t nlb, uint64_t count, uint64_t lba) "cid %"PRIu16" %s nsid %"PRIu32" nlb %"PRIu32" count %"PRIu64" lba 0x%"PRIx64""
 nvme_dev_rw_cb(uint16_t cid, uint32_t nsid) "cid %"PRIu16" nsid %"PRIu32""
 nvme_dev_write_zeros(uint16_t cid, uint32_t nsid, uint64_t slba, uint32_t nlb) "cid %"PRIu16" nsid %"PRIu32" slba %"PRIu64" nlb %"PRIu32""
 nvme_dev_create_sq(uint64_t addr, uint16_t sqid, uint16_t cqid, uint16_t qsize, uint16_t qflags) "create submission queue, addr=0x%"PRIx64", sqid=%"PRIu16", cqid=%"PRIu16", qsize=%"PRIu16", qflags=%"PRIu16""
@@ -94,7 +95,8 @@ nvme_dev_err_invalid_prplist_ent(uint64_t prplist) "PRP list entry is null or no
 nvme_dev_err_invalid_prp2_align(uint64_t prp2) "PRP2 is not page aligned: 0x%"PRIx64""
 nvme_dev_err_invalid_prp2_missing(void) "PRP2 is null and more data to be transferred"
 nvme_dev_err_invalid_prp(void) "invalid PRP"
-nvme_dev_err_invalid_ns(uint32_t ns, uint32_t limit) "invalid namespace %u not within 1-%u"
+nvme_dev_err_invalid_ns(uint32_t nsid, uint32_t nn) "nsid %"PRIu32" nn %"PRIu32""
+nvme_dev_err_inactive_ns(uint32_t nsid, uint32_t nn) "nsid %"PRIu32" nn %"PRIu32""
 nvme_dev_err_invalid_opc(uint8_t opc) "invalid opcode 0x%"PRIx8""
 nvme_dev_err_invalid_admin_opc(uint8_t opc) "invalid admin opcode 0x%"PRIx8""
 nvme_dev_err_invalid_lba_range(uint64_t start, uint64_t len, uint64_t limit) "Invalid LBA start=%"PRIu64" len=%"PRIu64" limit=%"PRIu64""
-- 
2.25.0