[PATCH v5 17/26] nvme: allow multiple aios per command

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

This refactors how the device issues asynchronous block backend
requests. The NvmeRequest now holds a queue of NvmeAIOs that are
associated with the command. This allows multiple aios to be issued for
a command. Only when all requests have been completed will the device
post a completion queue entry.

Because the device is currently guaranteed to only issue a single aio
request per command, the benefit is not immediately obvious. But this
functionality is required to support metadata, the dataset management
command and other features.

Signed-off-by: Klaus Jensen <klaus.jensen@cnexlabs.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
---
 hw/block/nvme.c       | 449 +++++++++++++++++++++++++++++++++---------
 hw/block/nvme.h       | 134 +++++++++++--
 hw/block/trace-events |   8 +
 3 files changed, 480 insertions(+), 111 deletions(-)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 334265efb21e..e97da35c4ca1 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -19,7 +19,8 @@
  *      -drive file=<file>,if=none,id=<drive_id>
  *      -device nvme,drive=<drive_id>,serial=<serial>,id=<id[optional]>, \
  *              cmb_size_mb=<cmb_size_mb[optional]>, \
- *              num_queues=<N[optional]>
+ *              num_queues=<N[optional]>, \
+ *              mdts=<mdts[optional]>
  *
  * 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.
@@ -57,6 +58,7 @@
     } while (0)
 
 static void nvme_process_sq(void *opaque);
+static void nvme_aio_cb(void *opaque, int ret);
 
 static inline void *nvme_addr_to_cmb(NvmeCtrl *n, hwaddr addr)
 {
@@ -341,6 +343,107 @@ static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
     return status;
 }
 
+static uint16_t nvme_map(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
+{
+    NvmeNamespace *ns = req->ns;
+
+    uint32_t len = req->nlb << nvme_ns_lbads(ns);
+    uint64_t prp1 = le64_to_cpu(cmd->prp1);
+    uint64_t prp2 = le64_to_cpu(cmd->prp2);
+
+    return nvme_map_prp(n, &req->qsg, &req->iov, prp1, prp2, len, req);
+}
+
+static void nvme_aio_destroy(NvmeAIO *aio)
+{
+    g_free(aio);
+}
+
+static inline void nvme_req_register_aio(NvmeRequest *req, NvmeAIO *aio,
+    NvmeAIOOp opc)
+{
+    aio->opc = opc;
+
+    trace_nvme_dev_req_register_aio(nvme_cid(req), aio, blk_name(aio->blk),
+        aio->offset, aio->len, nvme_aio_opc_str(aio), req);
+
+    if (req) {
+        QTAILQ_INSERT_TAIL(&req->aio_tailq, aio, tailq_entry);
+    }
+}
+
+static void nvme_aio(NvmeAIO *aio)
+{
+    BlockBackend *blk = aio->blk;
+    BlockAcctCookie *acct = &aio->acct;
+    BlockAcctStats *stats = blk_get_stats(blk);
+
+    bool is_write, dma;
+
+    switch (aio->opc) {
+    case NVME_AIO_OPC_NONE:
+        break;
+
+    case NVME_AIO_OPC_FLUSH:
+        block_acct_start(stats, acct, 0, BLOCK_ACCT_FLUSH);
+        aio->aiocb = blk_aio_flush(blk, nvme_aio_cb, aio);
+        break;
+
+    case NVME_AIO_OPC_WRITE_ZEROES:
+        block_acct_start(stats, acct, aio->len, BLOCK_ACCT_WRITE);
+        aio->aiocb = blk_aio_pwrite_zeroes(blk, aio->offset, aio->len,
+            BDRV_REQ_MAY_UNMAP, nvme_aio_cb, aio);
+        break;
+
+    case NVME_AIO_OPC_READ:
+    case NVME_AIO_OPC_WRITE:
+        dma = aio->qsg != NULL;
+        is_write = (aio->opc == NVME_AIO_OPC_WRITE);
+
+        block_acct_start(stats, acct, aio->len,
+            is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
+
+        if (dma) {
+            aio->aiocb = is_write ?
+                dma_blk_write(blk, aio->qsg, aio->offset,
+                    BDRV_SECTOR_SIZE, nvme_aio_cb, aio) :
+                dma_blk_read(blk, aio->qsg, aio->offset,
+                    BDRV_SECTOR_SIZE, nvme_aio_cb, aio);
+
+            return;
+        }
+
+        aio->aiocb = is_write ?
+            blk_aio_pwritev(blk, aio->offset, aio->iov, 0,
+                nvme_aio_cb, aio) :
+            blk_aio_preadv(blk, aio->offset, aio->iov, 0,
+                nvme_aio_cb, aio);
+
+        break;
+    }
+}
+
+static void nvme_rw_aio(BlockBackend *blk, uint64_t offset, NvmeRequest *req)
+{
+    NvmeAIO *aio;
+    size_t len = req->qsg.nsg > 0 ? req->qsg.size : req->iov.size;
+
+    aio = g_new0(NvmeAIO, 1);
+
+    *aio = (NvmeAIO) {
+        .blk = blk,
+        .offset = offset,
+        .len = len,
+        .req = req,
+        .qsg = &req->qsg,
+        .iov = &req->iov,
+    };
+
+    nvme_req_register_aio(req, aio, nvme_req_is_write(req) ?
+        NVME_AIO_OPC_WRITE : NVME_AIO_OPC_READ);
+    nvme_aio(aio);
+}
+
 static void nvme_post_cqes(void *opaque)
 {
     NvmeCQueue *cq = opaque;
@@ -364,6 +467,7 @@ static void nvme_post_cqes(void *opaque)
         nvme_inc_cq_tail(cq);
         pci_dma_write(&n->parent_obj, addr, (void *)&req->cqe,
             sizeof(req->cqe));
+        nvme_req_clear(req);
         QTAILQ_INSERT_TAIL(&sq->req_list, req, entry);
     }
     if (cq->tail != cq->head) {
@@ -374,8 +478,8 @@ static void nvme_post_cqes(void *opaque)
 static void nvme_enqueue_req_completion(NvmeCQueue *cq, NvmeRequest *req)
 {
     assert(cq->cqid == req->sq->cqid);
-    trace_nvme_dev_enqueue_req_completion(nvme_cid(req), cq->cqid,
-        req->status);
+    trace_nvme_dev_enqueue_req_completion(nvme_cid(req), cq->cqid, req->status);
+
     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);
@@ -460,135 +564,272 @@ static void nvme_clear_events(NvmeCtrl *n, uint8_t event_type)
     }
 }
 
-static void nvme_rw_cb(void *opaque, int ret)
+static inline uint16_t nvme_check_mdts(NvmeCtrl *n, size_t len,
+    NvmeRequest *req)
+{
+    uint8_t mdts = n->params.mdts;
+
+    if (mdts && len > n->page_size << mdts) {
+        trace_nvme_dev_err_mdts(nvme_cid(req), n->page_size << mdts, len);
+        return NVME_INVALID_FIELD | NVME_DNR;
+    }
+
+    return NVME_SUCCESS;
+}
+
+static inline uint16_t nvme_check_prinfo(NvmeCtrl *n, NvmeRequest *req)
+{
+    NvmeRwCmd *rw = (NvmeRwCmd *) &req->cmd;
+    NvmeNamespace *ns = req->ns;
+
+    uint16_t ctrl = le16_to_cpu(rw->control);
+
+    if ((ctrl & NVME_RW_PRINFO_PRACT) && !(ns->id_ns.dps & DPS_TYPE_MASK)) {
+        trace_nvme_dev_err_prinfo(nvme_cid(req), ctrl);
+        return NVME_INVALID_FIELD | NVME_DNR;
+    }
+
+    return NVME_SUCCESS;
+}
+
+static inline uint16_t nvme_check_bounds(NvmeCtrl *n, uint64_t slba,
+    uint32_t nlb, NvmeRequest *req)
+{
+    NvmeNamespace *ns = req->ns;
+    uint64_t nsze = le64_to_cpu(ns->id_ns.nsze);
+
+    if (unlikely((slba + nlb) > nsze)) {
+        block_acct_invalid(blk_get_stats(n->conf.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;
+    }
+
+    return NVME_SUCCESS;
+}
+
+static uint16_t nvme_check_rw(NvmeCtrl *n, NvmeRequest *req)
+{
+    NvmeNamespace *ns = req->ns;
+    size_t len = req->nlb << nvme_ns_lbads(ns);
+    uint16_t status;
+
+    status = nvme_check_mdts(n, len, req);
+    if (status) {
+        return status;
+    }
+
+    status = nvme_check_prinfo(n, req);
+    if (status) {
+        return status;
+    }
+
+    status = nvme_check_bounds(n, req->slba, req->nlb, req);
+    if (status) {
+        return status;
+    }
+
+    return NVME_SUCCESS;
+}
+
+static void nvme_rw_cb(NvmeRequest *req, void *opaque)
 {
-    NvmeRequest *req = opaque;
     NvmeSQueue *sq = req->sq;
     NvmeCtrl *n = sq->ctrl;
     NvmeCQueue *cq = n->cq[sq->cqid];
 
-    if (!ret) {
-        block_acct_done(blk_get_stats(n->conf.blk), &req->acct);
-        req->status = NVME_SUCCESS;
-    } else {
-        block_acct_failed(blk_get_stats(n->conf.blk), &req->acct);
-        req->status = NVME_INTERNAL_DEV_ERROR;
-    }
-
-    if (req->qsg.nalloc) {
-        qemu_sglist_destroy(&req->qsg);
-    }
-    if (req->iov.nalloc) {
-        qemu_iovec_destroy(&req->iov);
-    }
+    trace_nvme_dev_rw_cb(nvme_cid(req), req->cmd.nsid);
 
     nvme_enqueue_req_completion(cq, req);
 }
 
-static uint16_t nvme_flush(NvmeCtrl *n, NvmeNamespace *ns, NvmeCmd *cmd,
-    NvmeRequest *req)
+static void nvme_aio_cb(void *opaque, int ret)
 {
-    block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,
-         BLOCK_ACCT_FLUSH);
-    req->aiocb = blk_aio_flush(n->conf.blk, nvme_rw_cb, req);
+    NvmeAIO *aio = opaque;
+    NvmeRequest *req = aio->req;
 
-    return NVME_NO_COMPLETE;
-}
+    BlockBackend *blk = aio->blk;
+    BlockAcctCookie *acct = &aio->acct;
+    BlockAcctStats *stats = blk_get_stats(blk);
 
-static uint16_t nvme_write_zeros(NvmeCtrl *n, NvmeNamespace *ns, NvmeCmd *cmd,
-    NvmeRequest *req)
-{
-    NvmeRwCmd *rw = (NvmeRwCmd *)cmd;
-    const uint8_t lba_index = NVME_ID_NS_FLBAS_INDEX(ns->id_ns.flbas);
-    const uint8_t data_shift = ns->id_ns.lbaf[lba_index].ds;
-    uint64_t slba = le64_to_cpu(rw->slba);
-    uint32_t nlb  = le16_to_cpu(rw->nlb) + 1;
-    uint64_t offset = slba << data_shift;
-    uint32_t count = nlb << data_shift;
-
-    if (unlikely(slba + nlb > ns->id_ns.nsze)) {
-        trace_nvme_dev_err_invalid_lba_range(slba, nlb, ns->id_ns.nsze);
-        return NVME_LBA_RANGE | NVME_DNR;
-    }
-
-    block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,
-                     BLOCK_ACCT_WRITE);
-    req->aiocb = blk_aio_pwrite_zeroes(n->conf.blk, offset, count,
-                                        BDRV_REQ_MAY_UNMAP, nvme_rw_cb, req);
-    return NVME_NO_COMPLETE;
-}
-
-static uint16_t nvme_rw(NvmeCtrl *n, NvmeNamespace *ns, NvmeCmd *cmd,
-    NvmeRequest *req)
-{
-    NvmeRwCmd *rw = (NvmeRwCmd *)cmd;
-    uint32_t nlb  = le32_to_cpu(rw->nlb) + 1;
-    uint64_t slba = le64_to_cpu(rw->slba);
-    uint64_t prp1 = le64_to_cpu(rw->prp1);
-    uint64_t prp2 = le64_to_cpu(rw->prp2);
-
-    uint8_t lba_index  = NVME_ID_NS_FLBAS_INDEX(ns->id_ns.flbas);
-    uint8_t data_shift = ns->id_ns.lbaf[lba_index].ds;
-    uint64_t data_size = (uint64_t)nlb << data_shift;
-    uint64_t data_offset = slba << data_shift;
-    int is_write = rw->opcode == NVME_CMD_WRITE ? 1 : 0;
-    enum BlockAcctType acct = is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ;
+    Error *local_err = NULL;
 
-    trace_nvme_dev_rw(is_write ? "write" : "read", nlb, data_size, slba);
+    trace_nvme_dev_aio_cb(nvme_cid(req), aio, blk_name(blk), aio->offset,
+        nvme_aio_opc_str(aio), req);
 
-    if (unlikely((slba + nlb) > ns->id_ns.nsze)) {
-        block_acct_invalid(blk_get_stats(n->conf.blk), acct);
-        trace_nvme_dev_err_invalid_lba_range(slba, nlb, ns->id_ns.nsze);
-        return NVME_LBA_RANGE | NVME_DNR;
+    if (req) {
+        QTAILQ_REMOVE(&req->aio_tailq, aio, tailq_entry);
     }
 
-    if (nvme_map_prp(n, &req->qsg, &req->iov, prp1, prp2, data_size, req)) {
-        block_acct_invalid(blk_get_stats(n->conf.blk), acct);
-        return NVME_INVALID_FIELD | NVME_DNR;
-    }
-
-    if (req->qsg.nsg > 0) {
-        block_acct_start(blk_get_stats(n->conf.blk), &req->acct, req->qsg.size,
-            acct);
-
-        req->aiocb = is_write ?
-            dma_blk_write(n->conf.blk, &req->qsg, data_offset, BDRV_SECTOR_SIZE,
-                          nvme_rw_cb, req) :
-            dma_blk_read(n->conf.blk, &req->qsg, data_offset, BDRV_SECTOR_SIZE,
-                         nvme_rw_cb, req);
+    if (!ret) {
+        block_acct_done(stats, acct);
     } else {
-        block_acct_start(blk_get_stats(n->conf.blk), &req->acct, req->iov.size,
-            acct);
+        block_acct_failed(stats, acct);
 
-        req->aiocb = is_write ?
-            blk_aio_pwritev(n->conf.blk, data_offset, &req->iov, 0, nvme_rw_cb,
-                            req) :
-            blk_aio_preadv(n->conf.blk, data_offset, &req->iov, 0, nvme_rw_cb,
-                           req);
+        if (req) {
+            uint16_t status;
+
+            switch (aio->opc) {
+            case NVME_AIO_OPC_READ:
+                status = NVME_UNRECOVERED_READ;
+                break;
+            case NVME_AIO_OPC_WRITE:
+            case NVME_AIO_OPC_WRITE_ZEROES:
+                status = NVME_WRITE_FAULT;
+                break;
+            default:
+                status = NVME_INTERNAL_DEV_ERROR;
+                break;
+            }
+
+            trace_nvme_dev_err_aio(nvme_cid(req), aio, blk_name(blk),
+                aio->offset, nvme_aio_opc_str(aio), req, status);
+
+            error_setg_errno(&local_err, -ret, "aio failed");
+            error_report_err(local_err);
+
+            /*
+             * An Internal Error trumps all other errors. For other errors,
+             * only set the first error encountered. Any additional errors will
+             * be recorded in the error information log page.
+             */
+            if (!req->status ||
+                nvme_status_is_error(status, NVME_INTERNAL_DEV_ERROR)) {
+                req->status = status;
+            }
+        }
+    }
+
+    if (aio->cb) {
+        aio->cb(aio, aio->cb_arg, ret);
+    }
+
+    if (req && QTAILQ_EMPTY(&req->aio_tailq)) {
+        if (req->cb) {
+            req->cb(req, req->cb_arg);
+        } else {
+            NvmeSQueue *sq = req->sq;
+            NvmeCtrl *n = sq->ctrl;
+            NvmeCQueue *cq = n->cq[sq->cqid];
+
+            nvme_enqueue_req_completion(cq, req);
+        }
     }
 
+    nvme_aio_destroy(aio);
+}
+
+static uint16_t nvme_flush(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
+{
+    NvmeAIO *aio = g_new0(NvmeAIO, 1);
+
+    *aio = (NvmeAIO) {
+        .blk = n->conf.blk,
+        .req = req,
+    };
+
+    nvme_req_register_aio(req, aio, NVME_AIO_OPC_FLUSH);
+    nvme_aio(aio);
+
+    return NVME_NO_COMPLETE;
+}
+
+static uint16_t nvme_write_zeros(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
+{
+    NvmeAIO *aio;
+
+    NvmeNamespace *ns = req->ns;
+    NvmeRwCmd *rw = (NvmeRwCmd *) cmd;
+
+    int64_t offset;
+    size_t count;
+    uint16_t status;
+
+    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);
+
+    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);
+        return status;
+    }
+
+    offset = req->slba << nvme_ns_lbads(ns);
+    count = req->nlb << nvme_ns_lbads(ns);
+
+    aio = g_new0(NvmeAIO, 1);
+
+    *aio = (NvmeAIO) {
+        .blk = n->conf.blk,
+        .offset = offset,
+        .len = count,
+        .req = req,
+    };
+
+    nvme_req_register_aio(req, aio, NVME_AIO_OPC_WRITE_ZEROES);
+    nvme_aio(aio);
+
+    return NVME_NO_COMPLETE;
+}
+
+static uint16_t nvme_rw(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
+{
+    NvmeRwCmd *rw = (NvmeRwCmd *) cmd;
+    NvmeNamespace *ns = req->ns;
+    int status;
+
+    enum BlockAcctType acct =
+        nvme_req_is_write(req) ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ;
+
+    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);
+
+    status = nvme_check_rw(n, req);
+    if (status) {
+        block_acct_invalid(blk_get_stats(n->conf.blk), acct);
+        return status;
+    }
+
+    status = nvme_map(n, cmd, req);
+    if (status) {
+        block_acct_invalid(blk_get_stats(n->conf.blk), acct);
+        return status;
+    }
+
+    nvme_rw_aio(n->conf.blk, req->slba << nvme_ns_lbads(ns), req);
+    nvme_req_set_cb(req, nvme_rw_cb, NULL);
+
     return NVME_NO_COMPLETE;
 }
 
 static uint16_t nvme_io_cmd(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
 {
-    NvmeNamespace *ns;
     uint32_t nsid = le32_to_cpu(cmd->nsid);
 
+    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;
     }
 
-    ns = &n->namespaces[nsid - 1];
+    req->ns = &n->namespaces[nsid - 1];
+
     switch (cmd->opcode) {
     case NVME_CMD_FLUSH:
-        return nvme_flush(n, ns, cmd, req);
+        return nvme_flush(n, cmd, req);
     case NVME_CMD_WRITE_ZEROS:
-        return nvme_write_zeros(n, ns, cmd, req);
+        return nvme_write_zeros(n, cmd, req);
     case NVME_CMD_WRITE:
     case NVME_CMD_READ:
-        return nvme_rw(n, ns, cmd, req);
+        return nvme_rw(n, cmd, req);
     default:
         trace_nvme_dev_err_invalid_opc(cmd->opcode);
         return NVME_INVALID_OPCODE | NVME_DNR;
@@ -612,6 +853,7 @@ static uint16_t nvme_del_sq(NvmeCtrl *n, NvmeCmd *cmd)
     NvmeRequest *req, *next;
     NvmeSQueue *sq;
     NvmeCQueue *cq;
+    NvmeAIO *aio;
     uint16_t qid = le16_to_cpu(c->qid);
 
     if (unlikely(!qid || nvme_check_sqid(n, qid))) {
@@ -624,8 +866,11 @@ static uint16_t nvme_del_sq(NvmeCtrl *n, NvmeCmd *cmd)
     sq = n->sq[qid];
     while (!QTAILQ_EMPTY(&sq->out_req_list)) {
         req = QTAILQ_FIRST(&sq->out_req_list);
-        assert(req->aiocb);
-        blk_aio_cancel(req->aiocb);
+        while (!QTAILQ_EMPTY(&req->aio_tailq)) {
+            aio = QTAILQ_FIRST(&req->aio_tailq);
+            assert(aio->aiocb);
+            blk_aio_cancel(aio->aiocb);
+        }
     }
     if (!nvme_check_cqid(n, sq->cqid)) {
         cq = n->cq[sq->cqid];
@@ -662,6 +907,7 @@ static void nvme_init_sq(NvmeSQueue *sq, NvmeCtrl *n, uint64_t dma_addr,
     QTAILQ_INIT(&sq->out_req_list);
     for (i = 0; i < sq->size; i++) {
         sq->io_req[i].sq = sq;
+        QTAILQ_INIT(&(sq->io_req[i].aio_tailq));
         QTAILQ_INSERT_TAIL(&(sq->req_list), &sq->io_req[i], entry);
     }
     sq->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, nvme_process_sq, sq);
@@ -800,6 +1046,7 @@ static uint16_t nvme_get_log(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
     uint32_t numdl, numdu;
     uint64_t off, lpol, lpou;
     size_t   len;
+    uint16_t status;
 
     numdl = (dw10 >> 16);
     numdu = (dw11 & 0xffff);
@@ -815,6 +1062,11 @@ static uint16_t nvme_get_log(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
 
     trace_nvme_dev_get_log(nvme_cid(req), lid, lsp, rae, len, off);
 
+    status = nvme_check_mdts(n, len, req);
+    if (status) {
+        return status;
+    }
+
     switch (lid) {
     case NVME_LOG_ERROR_INFO:
         if (!rae) {
@@ -1348,7 +1600,7 @@ static void nvme_process_sq(void *opaque)
         req = QTAILQ_FIRST(&sq->req_list);
         QTAILQ_REMOVE(&sq->req_list, req, entry);
         QTAILQ_INSERT_TAIL(&sq->out_req_list, req, entry);
-        memset(&req->cqe, 0, sizeof(req->cqe));
+
         req->cqe.cid = cmd.cid;
         memcpy(&req->cmd, &cmd, sizeof(NvmeCmd));
 
@@ -1928,6 +2180,7 @@ static void nvme_init_ctrl(NvmeCtrl *n)
     id->ieee[0] = 0x00;
     id->ieee[1] = 0x02;
     id->ieee[2] = 0xb3;
+    id->mdts = params->mdts;
     id->ver = cpu_to_le32(NVME_SPEC_VER);
     id->oacs = cpu_to_le16(0);
 
diff --git a/hw/block/nvme.h b/hw/block/nvme.h
index d27baa9d5391..3319f8edd7e1 100644
--- a/hw/block/nvme.h
+++ b/hw/block/nvme.h
@@ -8,7 +8,8 @@
     DEFINE_PROP_UINT32("cmb_size_mb", _state, _props.cmb_size_mb, 0), \
     DEFINE_PROP_UINT32("num_queues", _state, _props.num_queues, 64), \
     DEFINE_PROP_UINT8("aerl", _state, _props.aerl, 3), \
-    DEFINE_PROP_UINT32("aer_max_queued", _state, _props.aer_max_queued, 64)
+    DEFINE_PROP_UINT32("aer_max_queued", _state, _props.aer_max_queued, 64), \
+    DEFINE_PROP_UINT8("mdts", _state, _props.mdts, 7)
 
 typedef struct NvmeParams {
     char     *serial;
@@ -16,6 +17,7 @@ typedef struct NvmeParams {
     uint32_t cmb_size_mb;
     uint8_t  aerl;
     uint32_t aer_max_queued;
+    uint8_t  mdts;
 } NvmeParams;
 
 typedef struct NvmeAsyncEvent {
@@ -23,17 +25,58 @@ typedef struct NvmeAsyncEvent {
     NvmeAerResult result;
 } NvmeAsyncEvent;
 
-typedef struct NvmeRequest {
-    struct NvmeSQueue       *sq;
-    BlockAIOCB              *aiocb;
-    uint16_t                status;
-    NvmeCqe                 cqe;
-    BlockAcctCookie         acct;
-    QEMUSGList              qsg;
-    QEMUIOVector            iov;
-    NvmeCmd                 cmd;
-    QTAILQ_ENTRY(NvmeRequest)entry;
-} NvmeRequest;
+typedef struct NvmeRequest NvmeRequest;
+typedef void NvmeRequestCompletionFunc(NvmeRequest *req, void *opaque);
+
+struct NvmeRequest {
+    struct NvmeSQueue    *sq;
+    struct NvmeNamespace *ns;
+
+    NvmeCqe  cqe;
+    NvmeCmd  cmd;
+    uint16_t status;
+
+    uint64_t slba;
+    uint32_t nlb;
+
+    QEMUSGList   qsg;
+    QEMUIOVector iov;
+
+    NvmeRequestCompletionFunc *cb;
+    void                      *cb_arg;
+
+    QTAILQ_HEAD(, NvmeAIO)    aio_tailq;
+    QTAILQ_ENTRY(NvmeRequest) entry;
+};
+
+static inline void nvme_req_clear(NvmeRequest *req)
+{
+    req->ns = NULL;
+    memset(&req->cqe, 0, sizeof(req->cqe));
+    req->status = NVME_SUCCESS;
+    req->slba = req->nlb = 0x0;
+    req->cb = req->cb_arg = NULL;
+
+    if (req->qsg.sg) {
+        qemu_sglist_destroy(&req->qsg);
+    }
+
+    if (req->iov.iov) {
+        qemu_iovec_destroy(&req->iov);
+    }
+}
+
+static inline void nvme_req_set_cb(NvmeRequest *req,
+    NvmeRequestCompletionFunc *cb, void *cb_arg)
+{
+    req->cb = cb;
+    req->cb_arg = cb_arg;
+}
+
+static inline void nvme_req_clear_cb(NvmeRequest *req)
+{
+    req->cb = req->cb_arg = NULL;
+}
 
 typedef struct NvmeSQueue {
     struct NvmeCtrl *ctrl;
@@ -85,6 +128,60 @@ 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,
+    NVME_AIO_OPC_READ         = 0x2,
+    NVME_AIO_OPC_WRITE        = 0x3,
+    NVME_AIO_OPC_WRITE_ZEROES = 0x4,
+} NvmeAIOOp;
+
+typedef struct NvmeAIO NvmeAIO;
+typedef void NvmeAIOCompletionFunc(NvmeAIO *aio, void *opaque, int ret);
+
+struct NvmeAIO {
+    NvmeRequest *req;
+
+    NvmeAIOOp       opc;
+    int64_t         offset;
+    size_t          len;
+    BlockBackend    *blk;
+    BlockAIOCB      *aiocb;
+    BlockAcctCookie acct;
+
+    NvmeAIOCompletionFunc *cb;
+    void                  *cb_arg;
+
+    QEMUSGList   *qsg;
+    QEMUIOVector *iov;
+
+    QTAILQ_ENTRY(NvmeAIO) tailq_entry;
+};
+
+static inline const char *nvme_aio_opc_str(NvmeAIO *aio)
+{
+    switch (aio->opc) {
+    case NVME_AIO_OPC_NONE:         return "NVME_AIO_OP_NONE";
+    case NVME_AIO_OPC_FLUSH:        return "NVME_AIO_OP_FLUSH";
+    case NVME_AIO_OPC_READ:         return "NVME_AIO_OP_READ";
+    case NVME_AIO_OPC_WRITE:        return "NVME_AIO_OP_WRITE";
+    case NVME_AIO_OPC_WRITE_ZEROES: return "NVME_AIO_OP_WRITE_ZEROES";
+    default:                        return "NVME_AIO_OP_UNKNOWN";
+    }
+}
+
+static inline bool nvme_req_is_write(NvmeRequest *req)
+{
+    switch (req->cmd.opcode) {
+    case NVME_CMD_WRITE:
+    case NVME_CMD_WRITE_UNCOR:
+    case NVME_CMD_WRITE_ZEROS:
+        return true;
+    default:
+        return false;
+    }
+}
+
 #define TYPE_NVME "nvme"
 #define NVME(obj) \
         OBJECT_CHECK(NvmeCtrl, (obj), TYPE_NVME)
@@ -139,10 +236,21 @@ static inline uint64_t nvme_ns_nlbas(NvmeCtrl *n, NvmeNamespace *ns)
 static inline uint16_t nvme_cid(NvmeRequest *req)
 {
     if (req) {
-        return le16_to_cpu(req->cqe.cid);
+        return le16_to_cpu(req->cmd.cid);
     }
 
     return 0xffff;
 }
 
+static inline bool nvme_status_is_error(uint16_t status, uint16_t err)
+{
+    /* strip DNR and MORE */
+    return (status & 0xfff) == err;
+}
+
+static inline NvmeCtrl *nvme_ctrl(NvmeRequest *req)
+{
+    return req->sq->ctrl;
+}
+
 #endif /* HW_NVME_H */
diff --git a/hw/block/trace-events b/hw/block/trace-events
index 77aa0da99ee0..90a57fb6099a 100644
--- a/hw/block/trace-events
+++ b/hw/block/trace-events
@@ -34,7 +34,12 @@ nvme_dev_irq_pin(void) "pulsing IRQ pin"
 nvme_dev_irq_masked(void) "IRQ is masked"
 nvme_dev_dma_read(uint64_t prp1, uint64_t prp2) "DMA read, prp1=0x%"PRIx64" prp2=0x%"PRIx64""
 nvme_dev_map_prp(uint16_t cid, uint8_t opc, uint64_t trans_len, uint32_t len, uint64_t prp1, uint64_t prp2, int num_prps) "cid %"PRIu16" opc 0x%"PRIx8" trans_len %"PRIu64" len %"PRIu32" prp1 0x%"PRIx64" prp2 0x%"PRIx64" num_prps %d"
+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_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""
 nvme_dev_create_cq(uint64_t addr, uint16_t cqid, uint16_t vector, uint16_t size, uint16_t qflags, int ien) "create completion queue, addr=0x%"PRIx64", cqid=%"PRIu16", vector=%"PRIu16", qsize=%"PRIu16", qflags=%"PRIu16", ien=%d"
 nvme_dev_del_sq(uint16_t qid) "deleting submission queue sqid=%"PRIu16""
@@ -75,6 +80,9 @@ nvme_dev_mmio_shutdown_set(void) "shutdown bit set"
 nvme_dev_mmio_shutdown_cleared(void) "shutdown bit cleared"
 
 # nvme traces for error conditions
+nvme_dev_err_mdts(uint16_t cid, size_t mdts, size_t len) "cid %"PRIu16" mdts %"PRIu64" len %"PRIu64""
+nvme_dev_err_prinfo(uint16_t cid, uint16_t ctrl) "cid %"PRIu16" ctrl %"PRIu16""
+nvme_dev_err_aio(uint16_t cid, void *aio, const char *blkname, uint64_t offset, const char *opc, void *req, uint16_t status) "cid %"PRIu16" aio %p blk \"%s\" offset %"PRIu64" opc \"%s\" req %p status 0x%"PRIx16""
 nvme_dev_err_invalid_dma(void) "PRP/SGL is too small for transfer size"
 nvme_dev_err_invalid_prplist_ent(uint64_t prplist) "PRP list entry is null or not page aligned: 0x%"PRIx64""
 nvme_dev_err_invalid_prp2_align(uint64_t prp2) "PRP2 is not page aligned: 0x%"PRIx64""
-- 
2.25.0