Archipelago » qemu

/*

 * QEMU NVM Express Controller

 *

 * Copyright (c) 2012, Intel Corporation

 *

 * Written by Keith Busch <keith.busch@intel.com>

 *

 * This code is licensed under the GNU GPL v2 or later.

 */

/**

 * Reference Specs: http://www.nvmexpress.org, 1.1, 1.0e

 *

 *  http://www.nvmexpress.org/resources/

 */

/**

 * Usage: add options:

 *      -drive file=<file>,if=none,id=<drive_id>

 *      -device nvme,drive=<drive_id>,serial=<serial>,id=<id[optional]>

 */

#include <hw/block/block.h>

#include <hw/hw.h>

#include <hw/pci/msix.h>

#include <hw/pci/pci.h>

#include "nvme.h"

static void nvme_process_sq(void *opaque);

static int nvme_check_sqid(NvmeCtrl *n, uint16_t sqid)

{

    return sqid < n->num_queues && n->sq[sqid] != NULL ? 0 : -1;

}

static int nvme_check_cqid(NvmeCtrl *n, uint16_t cqid)

{

    return cqid < n->num_queues && n->cq[cqid] != NULL ? 0 : -1;

}

static void nvme_inc_cq_tail(NvmeCQueue *cq)

{

    cq->tail++;

    if (cq->tail >= cq->size) {

        cq->tail = 0;

        cq->phase = !cq->phase;

    }

}

static void nvme_inc_sq_head(NvmeSQueue *sq)

{

    sq->head = (sq->head + 1) % sq->size;

}

static uint8_t nvme_cq_full(NvmeCQueue *cq)

{

    return (cq->tail + 1) % cq->size == cq->head;

}

static uint8_t nvme_sq_empty(NvmeSQueue *sq)

{

    return sq->head == sq->tail;

}

static void nvme_isr_notify(NvmeCtrl *n, NvmeCQueue *cq)

{

    if (cq->irq_enabled) {

        if (msix_enabled(&(n->parent_obj))) {

            msix_notify(&(n->parent_obj), cq->vector);

        } else {

            pci_irq_pulse(&n->parent_obj);

        }

    }

}

static uint16_t nvme_map_prp(QEMUSGList *qsg, uint64_t prp1, uint64_t prp2,

    uint32_t len, NvmeCtrl *n)

{

    hwaddr trans_len = n->page_size - (prp1 % n->page_size);

    trans_len = MIN(len, trans_len);

    int num_prps = (len >> n->page_bits) + 1;

    if (!prp1) {

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    pci_dma_sglist_init(qsg, &n->parent_obj, num_prps);

    qemu_sglist_add(qsg, prp1, trans_len);

    len -= trans_len;

    if (len) {

        if (!prp2) {

            goto unmap;

        }

        if (len > n->page_size) {

            uint64_t prp_list[n->max_prp_ents];

            uint32_t nents, prp_trans;

            int i = 0;

            nents = (len + n->page_size - 1) >> n->page_bits;

            prp_trans = MIN(n->max_prp_ents, nents) * sizeof(uint64_t);

            pci_dma_read(&n->parent_obj, prp2, (void *)prp_list, prp_trans);

            while (len != 0) {

                uint64_t prp_ent = le64_to_cpu(prp_list[i]);

                if (i == n->max_prp_ents - 1 && len > n->page_size) {

                    if (!prp_ent || prp_ent & (n->page_size - 1)) {

                        goto unmap;

                    }

                    i = 0;

                    nents = (len + n->page_size - 1) >> n->page_bits;

                    prp_trans = MIN(n->max_prp_ents, nents) * sizeof(uint64_t);

                    pci_dma_read(&n->parent_obj, prp_ent, (void *)prp_list,

                        prp_trans);

                    prp_ent = le64_to_cpu(prp_list[i]);

                }

                if (!prp_ent || prp_ent & (n->page_size - 1)) {

                    goto unmap;

                }

                trans_len = MIN(len, n->page_size);

                qemu_sglist_add(qsg, prp_ent, trans_len);

                len -= trans_len;

                i++;

            }

        } else {

            if (prp2 & (n->page_size - 1)) {

                goto unmap;

            }

            qemu_sglist_add(qsg, prp2, len);

        }

    }

    return NVME_SUCCESS;

 unmap:

    qemu_sglist_destroy(qsg);

    return NVME_INVALID_FIELD | NVME_DNR;

}

static uint16_t nvme_dma_read_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,

    uint64_t prp1, uint64_t prp2)

{

    QEMUSGList qsg;

    if (nvme_map_prp(&qsg, prp1, prp2, len, n)) {

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    if (dma_buf_read(ptr, len, &qsg)) {

        qemu_sglist_destroy(&qsg);

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    return NVME_SUCCESS;

}

static void nvme_post_cqes(void *opaque)

{

    NvmeCQueue *cq = opaque;

    NvmeCtrl *n = cq->ctrl;

    NvmeRequest *req, *next;

    QTAILQ_FOREACH_SAFE(req, &cq->req_list, entry, next) {

        NvmeSQueue *sq;

        hwaddr addr;

        if (nvme_cq_full(cq)) {

            break;

        }

        QTAILQ_REMOVE(&cq->req_list, req, entry);

        sq = req->sq;

        req->cqe.status = cpu_to_le16((req->status << 1) | cq->phase);

        req->cqe.sq_id = cpu_to_le16(sq->sqid);

        req->cqe.sq_head = cpu_to_le16(sq->head);

        addr = cq->dma_addr + cq->tail * n->cqe_size;

        nvme_inc_cq_tail(cq);

        pci_dma_write(&n->parent_obj, addr, (void *)&req->cqe,

            sizeof(req->cqe));

        QTAILQ_INSERT_TAIL(&sq->req_list, req, entry);

    }

    nvme_isr_notify(n, cq);

}

static void nvme_enqueue_req_completion(NvmeCQueue *cq, NvmeRequest *req)

{

    assert(cq->cqid == req->sq->cqid);

    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);

}

static void nvme_rw_cb(void *opaque, int ret)

{

    NvmeRequest *req = opaque;

    NvmeSQueue *sq = req->sq;

    NvmeCtrl *n = sq->ctrl;

    NvmeCQueue *cq = n->cq[sq->cqid];

    bdrv_acct_done(n->conf.bs, &req->acct);

    if (!ret) {

        req->status = NVME_SUCCESS;

    } else {

        req->status = NVME_INTERNAL_DEV_ERROR;

    }

    qemu_sglist_destroy(&req->qsg);

    nvme_enqueue_req_completion(cq, req);

}

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 = nlb << data_shift;

    uint64_t aio_slba  = slba << (data_shift - BDRV_SECTOR_BITS);

    int is_write = rw->opcode == NVME_CMD_WRITE ? 1 : 0;

    if ((slba + nlb) > ns->id_ns.nsze) {

        return NVME_LBA_RANGE | NVME_DNR;

    }

    if (nvme_map_prp(&req->qsg, prp1, prp2, data_size, n)) {

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    assert((nlb << data_shift) == req->qsg.size);

    dma_acct_start(n->conf.bs, &req->acct, &req->qsg, is_write ?

        BDRV_ACCT_WRITE : BDRV_ACCT_READ);

    req->aiocb = is_write ?

        dma_bdrv_write(n->conf.bs, &req->qsg, aio_slba, nvme_rw_cb, req) :

        dma_bdrv_read(n->conf.bs, &req->qsg, aio_slba, nvme_rw_cb, req);

    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);

    if (nsid == 0 || nsid > n->num_namespaces) {

        return NVME_INVALID_NSID | NVME_DNR;

    }

    ns = &n->namespaces[nsid - 1];

    switch (cmd->opcode) {

    case NVME_CMD_FLUSH:

        return NVME_SUCCESS;

    case NVME_CMD_WRITE:

    case NVME_CMD_READ:

        return nvme_rw(n, ns, cmd, req);

    default:

        return NVME_INVALID_OPCODE | NVME_DNR;

    }

}

static void nvme_free_sq(NvmeSQueue *sq, NvmeCtrl *n)

{

    n->sq[sq->sqid] = NULL;

    timer_del(sq->timer);

    timer_free(sq->timer);

    g_free(sq->io_req);

    if (sq->sqid) {

        g_free(sq);

    }

}

static uint16_t nvme_del_sq(NvmeCtrl *n, NvmeCmd *cmd)

{

    NvmeDeleteQ *c = (NvmeDeleteQ *)cmd;

    NvmeRequest *req, *next;

    NvmeSQueue *sq;

    NvmeCQueue *cq;

    uint16_t qid = le16_to_cpu(c->qid);

    if (!qid || nvme_check_sqid(n, qid)) {

        return NVME_INVALID_QID | NVME_DNR;

    }

    sq = n->sq[qid];

    while (!QTAILQ_EMPTY(&sq->out_req_list)) {

        req = QTAILQ_FIRST(&sq->out_req_list);

        assert(req->aiocb);

        bdrv_aio_cancel(req->aiocb);

    }

    if (!nvme_check_cqid(n, sq->cqid)) {

        cq = n->cq[sq->cqid];

        QTAILQ_REMOVE(&cq->sq_list, sq, entry);

        nvme_post_cqes(cq);

        QTAILQ_FOREACH_SAFE(req, &cq->req_list, entry, next) {

            if (req->sq == sq) {

                QTAILQ_REMOVE(&cq->req_list, req, entry);

                QTAILQ_INSERT_TAIL(&sq->req_list, req, entry);

            }

        }

    }

    nvme_free_sq(sq, n);

    return NVME_SUCCESS;

}

static void nvme_init_sq(NvmeSQueue *sq, NvmeCtrl *n, uint64_t dma_addr,

    uint16_t sqid, uint16_t cqid, uint16_t size)

{

    int i;

    NvmeCQueue *cq;

    sq->ctrl = n;

    sq->dma_addr = dma_addr;

    sq->sqid = sqid;

    sq->size = size;

    sq->cqid = cqid;

    sq->head = sq->tail = 0;

    sq->io_req = g_malloc(sq->size * sizeof(*sq->io_req));

    QTAILQ_INIT(&sq->req_list);

    QTAILQ_INIT(&sq->out_req_list);

    for (i = 0; i < sq->size; i++) {

        sq->io_req[i].sq = sq;

        QTAILQ_INSERT_TAIL(&(sq->req_list), &sq->io_req[i], entry);

    }

    sq->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, nvme_process_sq, sq);

    assert(n->cq[cqid]);

    cq = n->cq[cqid];

    QTAILQ_INSERT_TAIL(&(cq->sq_list), sq, entry);

    n->sq[sqid] = sq;

}

static uint16_t nvme_create_sq(NvmeCtrl *n, NvmeCmd *cmd)

{

    NvmeSQueue *sq;

    NvmeCreateSq *c = (NvmeCreateSq *)cmd;

    uint16_t cqid = le16_to_cpu(c->cqid);

    uint16_t sqid = le16_to_cpu(c->sqid);

    uint16_t qsize = le16_to_cpu(c->qsize);

    uint16_t qflags = le16_to_cpu(c->sq_flags);

    uint64_t prp1 = le64_to_cpu(c->prp1);

    if (!cqid || nvme_check_cqid(n, cqid)) {

        return NVME_INVALID_CQID | NVME_DNR;

    }

    if (!sqid || (sqid && !nvme_check_sqid(n, sqid))) {

        return NVME_INVALID_QID | NVME_DNR;

    }

    if (!qsize || qsize > NVME_CAP_MQES(n->bar.cap)) {

        return NVME_MAX_QSIZE_EXCEEDED | NVME_DNR;

    }

    if (!prp1 || prp1 & (n->page_size - 1)) {

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    if (!(NVME_SQ_FLAGS_PC(qflags))) {

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    sq = g_malloc0(sizeof(*sq));

    nvme_init_sq(sq, n, prp1, sqid, cqid, qsize + 1);

    return NVME_SUCCESS;

}

static void nvme_free_cq(NvmeCQueue *cq, NvmeCtrl *n)

{

    n->cq[cq->cqid] = NULL;

    timer_del(cq->timer);

    timer_free(cq->timer);

    msix_vector_unuse(&n->parent_obj, cq->vector);

    if (cq->cqid) {

        g_free(cq);

    }

}

static uint16_t nvme_del_cq(NvmeCtrl *n, NvmeCmd *cmd)

{

    NvmeDeleteQ *c = (NvmeDeleteQ *)cmd;

    NvmeCQueue *cq;

    uint16_t qid = le16_to_cpu(c->qid);

    if (!qid || nvme_check_cqid(n, qid)) {

        return NVME_INVALID_CQID | NVME_DNR;

    }

    cq = n->cq[qid];

    if (!QTAILQ_EMPTY(&cq->sq_list)) {

        return NVME_INVALID_QUEUE_DEL;

    }

    nvme_free_cq(cq, n);

    return NVME_SUCCESS;

}

static void nvme_init_cq(NvmeCQueue *cq, NvmeCtrl *n, uint64_t dma_addr,

    uint16_t cqid, uint16_t vector, uint16_t size, uint16_t irq_enabled)

{

    cq->ctrl = n;

    cq->cqid = cqid;

    cq->size = size;

    cq->dma_addr = dma_addr;

    cq->phase = 1;

    cq->irq_enabled = irq_enabled;

    cq->vector = vector;

    cq->head = cq->tail = 0;

    QTAILQ_INIT(&cq->req_list);

    QTAILQ_INIT(&cq->sq_list);

    msix_vector_use(&n->parent_obj, cq->vector);

    n->cq[cqid] = cq;

    cq->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, nvme_post_cqes, cq);

}

static uint16_t nvme_create_cq(NvmeCtrl *n, NvmeCmd *cmd)

{

    NvmeCQueue *cq;

    NvmeCreateCq *c = (NvmeCreateCq *)cmd;

    uint16_t cqid = le16_to_cpu(c->cqid);

    uint16_t vector = le16_to_cpu(c->irq_vector);

    uint16_t qsize = le16_to_cpu(c->qsize);

    uint16_t qflags = le16_to_cpu(c->cq_flags);

    uint64_t prp1 = le64_to_cpu(c->prp1);

    if (!cqid || (cqid && !nvme_check_cqid(n, cqid))) {

        return NVME_INVALID_CQID | NVME_DNR;

    }

    if (!qsize || qsize > NVME_CAP_MQES(n->bar.cap)) {

        return NVME_MAX_QSIZE_EXCEEDED | NVME_DNR;

    }

    if (!prp1) {

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    if (vector > n->num_queues) {

        return NVME_INVALID_IRQ_VECTOR | NVME_DNR;

    }

    if (!(NVME_CQ_FLAGS_PC(qflags))) {

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    cq = g_malloc0(sizeof(*cq));

    nvme_init_cq(cq, n, prp1, cqid, vector, qsize + 1,

        NVME_CQ_FLAGS_IEN(qflags));

    return NVME_SUCCESS;

}

static uint16_t nvme_identify(NvmeCtrl *n, NvmeCmd *cmd)

{

    NvmeNamespace *ns;

    NvmeIdentify *c = (NvmeIdentify *)cmd;

    uint32_t cns  = le32_to_cpu(c->cns);

    uint32_t nsid = le32_to_cpu(c->nsid);

    uint64_t prp1 = le64_to_cpu(c->prp1);

    uint64_t prp2 = le64_to_cpu(c->prp2);

    if (cns) {

        return nvme_dma_read_prp(n, (uint8_t *)&n->id_ctrl, sizeof(n->id_ctrl),

            prp1, prp2);

    }

    if (nsid == 0 || nsid > n->num_namespaces) {

        return NVME_INVALID_NSID | NVME_DNR;

    }

    ns = &n->namespaces[nsid - 1];

    return nvme_dma_read_prp(n, (uint8_t *)&ns->id_ns, sizeof(ns->id_ns),

        prp1, prp2);

}

static uint16_t nvme_get_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)

{

    uint32_t dw10 = le32_to_cpu(cmd->cdw10);

    switch (dw10) {

    case NVME_NUMBER_OF_QUEUES:

        req->cqe.result = cpu_to_le32(n->num_queues);

        break;

    default:

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    return NVME_SUCCESS;

}

static uint16_t nvme_set_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)

{

    uint32_t dw10 = le32_to_cpu(cmd->cdw10);

    switch (dw10) {

    case NVME_NUMBER_OF_QUEUES:

        req->cqe.result = cpu_to_le32(n->num_queues);

        break;

    default:

        return NVME_INVALID_FIELD | NVME_DNR;

    }

    return NVME_SUCCESS;

}

static uint16_t nvme_admin_cmd(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)

{

    switch (cmd->opcode) {

    case NVME_ADM_CMD_DELETE_SQ:

        return nvme_del_sq(n, cmd);

    case NVME_ADM_CMD_CREATE_SQ:

        return nvme_create_sq(n, cmd);

    case NVME_ADM_CMD_DELETE_CQ:

        return nvme_del_cq(n, cmd);

    case NVME_ADM_CMD_CREATE_CQ:

        return nvme_create_cq(n, cmd);

    case NVME_ADM_CMD_IDENTIFY:

        return nvme_identify(n, cmd);

    case NVME_ADM_CMD_SET_FEATURES:

        return nvme_set_feature(n, cmd, req);

    case NVME_ADM_CMD_GET_FEATURES:

        return nvme_get_feature(n, cmd, req);

    default:

        return NVME_INVALID_OPCODE | NVME_DNR;

    }

}

static void nvme_process_sq(void *opaque)

{

    NvmeSQueue *sq = opaque;

    NvmeCtrl *n = sq->ctrl;

    NvmeCQueue *cq = n->cq[sq->cqid];

    uint16_t status;

    hwaddr addr;

    NvmeCmd cmd;

    NvmeRequest *req;

    while (!(nvme_sq_empty(sq) || QTAILQ_EMPTY(&sq->req_list))) {

        addr = sq->dma_addr + sq->head * n->sqe_size;

        pci_dma_read(&n->parent_obj, addr, (void *)&cmd, sizeof(cmd));

        nvme_inc_sq_head(sq);

        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;

        status = sq->sqid ? nvme_io_cmd(n, &cmd, req) :

            nvme_admin_cmd(n, &cmd, req);

        if (status != NVME_NO_COMPLETE) {

            req->status = status;

            nvme_enqueue_req_completion(cq, req);

        }

    }

}

static void nvme_clear_ctrl(NvmeCtrl *n)

{

    int i;

    for (i = 0; i < n->num_queues; i++) {

        if (n->sq[i] != NULL) {

            nvme_free_sq(n->sq[i], n);

        }

    }

    for (i = 0; i < n->num_queues; i++) {

        if (n->cq[i] != NULL) {

            nvme_free_cq(n->cq[i], n);

        }

    }

    bdrv_flush(n->conf.bs);

    n->bar.cc = 0;

}

static int nvme_start_ctrl(NvmeCtrl *n)

{

    uint32_t page_bits = NVME_CC_MPS(n->bar.cc) + 12;

    uint32_t page_size = 1 << page_bits;

    if (n->cq[0] || n->sq[0] || !n->bar.asq || !n->bar.acq ||

            n->bar.asq & (page_size - 1) || n->bar.acq & (page_size - 1) ||

            NVME_CC_MPS(n->bar.cc) < NVME_CAP_MPSMIN(n->bar.cap) ||

            NVME_CC_MPS(n->bar.cc) > NVME_CAP_MPSMAX(n->bar.cap) ||

            NVME_CC_IOCQES(n->bar.cc) < NVME_CTRL_CQES_MIN(n->id_ctrl.cqes) ||

            NVME_CC_IOCQES(n->bar.cc) > NVME_CTRL_CQES_MAX(n->id_ctrl.cqes) ||

            NVME_CC_IOSQES(n->bar.cc) < NVME_CTRL_SQES_MIN(n->id_ctrl.sqes) ||

            NVME_CC_IOSQES(n->bar.cc) > NVME_CTRL_SQES_MAX(n->id_ctrl.sqes) ||

            !NVME_AQA_ASQS(n->bar.aqa) || NVME_AQA_ASQS(n->bar.aqa) > 4095 ||

            !NVME_AQA_ACQS(n->bar.aqa) || NVME_AQA_ACQS(n->bar.aqa) > 4095) {

        return -1;

    }

    n->page_bits = page_bits;

    n->page_size = page_size;

    n->max_prp_ents = n->page_size / sizeof(uint64_t);

    n->cqe_size = 1 << NVME_CC_IOCQES(n->bar.cc);

    n->sqe_size = 1 << NVME_CC_IOSQES(n->bar.cc);

    nvme_init_cq(&n->admin_cq, n, n->bar.acq, 0, 0,

        NVME_AQA_ACQS(n->bar.aqa) + 1, 1);

    nvme_init_sq(&n->admin_sq, n, n->bar.asq, 0, 0,

        NVME_AQA_ASQS(n->bar.aqa) + 1);

    return 0;

}

static void nvme_write_bar(NvmeCtrl *n, hwaddr offset, uint64_t data,

    unsigned size)

{

    switch (offset) {

    case 0xc:

        n->bar.intms |= data & 0xffffffff;

        n->bar.intmc = n->bar.intms;

        break;

    case 0x10:

        n->bar.intms &= ~(data & 0xffffffff);

        n->bar.intmc = n->bar.intms;

        break;

    case 0x14:

        if (NVME_CC_EN(data) && !NVME_CC_EN(n->bar.cc)) {

            n->bar.cc = data;

            if (nvme_start_ctrl(n)) {

                n->bar.csts = NVME_CSTS_FAILED;

            } else {

                n->bar.csts = NVME_CSTS_READY;

            }

        } else if (!NVME_CC_EN(data) && NVME_CC_EN(n->bar.cc)) {

            nvme_clear_ctrl(n);

            n->bar.csts &= ~NVME_CSTS_READY;

        }

        if (NVME_CC_SHN(data) && !(NVME_CC_SHN(n->bar.cc))) {

                nvme_clear_ctrl(n);

                n->bar.cc = data;

                n->bar.csts |= NVME_CSTS_SHST_COMPLETE;

        } else if (!NVME_CC_SHN(data) && NVME_CC_SHN(n->bar.cc)) {

                n->bar.csts &= ~NVME_CSTS_SHST_COMPLETE;

                n->bar.cc = data;

        }

        break;

    case 0x24:

        n->bar.aqa = data & 0xffffffff;

        break;

    case 0x28:

        n->bar.asq = data;

        break;

    case 0x2c:

        n->bar.asq |= data << 32;

        break;

    case 0x30:

        n->bar.acq = data;

        break;

    case 0x34:

        n->bar.acq |= data << 32;

        break;

    default:

        break;

    }

}

static uint64_t nvme_mmio_read(void *opaque, hwaddr addr, unsigned size)

{

    NvmeCtrl *n = (NvmeCtrl *)opaque;

    uint8_t *ptr = (uint8_t *)&n->bar;

    uint64_t val = 0;

    if (addr < sizeof(n->bar)) {

        memcpy(&val, ptr + addr, size);

    }

    return val;

}

static void nvme_process_db(NvmeCtrl *n, hwaddr addr, int val)

{

    uint32_t qid;

    if (addr & ((1 << 2) - 1)) {

        return;

    }

    if (((addr - 0x1000) >> 2) & 1) {

        uint16_t new_head = val & 0xffff;

        int start_sqs;

        NvmeCQueue *cq;

        qid = (addr - (0x1000 + (1 << 2))) >> 3;

        if (nvme_check_cqid(n, qid)) {

            return;

        }

        cq = n->cq[qid];

        if (new_head >= cq->size) {

            return;

        }

        start_sqs = nvme_cq_full(cq) ? 1 : 0;

        cq->head = new_head;

        if (start_sqs) {

            NvmeSQueue *sq;

            QTAILQ_FOREACH(sq, &cq->sq_list, entry) {

                timer_mod(sq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 500);

            }

            timer_mod(cq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 500);

        }

        if (cq->tail != cq->head) {

            nvme_isr_notify(n, cq);

        }

    } else {

        uint16_t new_tail = val & 0xffff;

        NvmeSQueue *sq;

        qid = (addr - 0x1000) >> 3;

        if (nvme_check_sqid(n, qid)) {

            return;

        }

        sq = n->sq[qid];

        if (new_tail >= sq->size) {

            return;

        }

        sq->tail = new_tail;

        timer_mod(sq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 500);

    }

}

static void nvme_mmio_write(void *opaque, hwaddr addr, uint64_t data,

    unsigned size)

{

    NvmeCtrl *n = (NvmeCtrl *)opaque;

    if (addr < sizeof(n->bar)) {

        nvme_write_bar(n, addr, data, size);

    } else if (addr >= 0x1000) {

        nvme_process_db(n, addr, data);

    }

}

static const MemoryRegionOps nvme_mmio_ops = {

    .read = nvme_mmio_read,

    .write = nvme_mmio_write,

    .endianness = DEVICE_LITTLE_ENDIAN,

    .impl = {

        .min_access_size = 2,

        .max_access_size = 8,

    },

};

static int nvme_init(PCIDevice *pci_dev)

{

    NvmeCtrl *n = NVME(pci_dev);

    NvmeIdCtrl *id = &n->id_ctrl;

    int i;

    int64_t bs_size;

    uint8_t *pci_conf;

    if (!(n->conf.bs)) {

        return -1;

    }

    bs_size =  bdrv_getlength(n->conf.bs);

    if (bs_size <= 0) {

        return -1;

    }

    blkconf_serial(&n->conf, &n->serial);

    if (!n->serial) {

        return -1;

    }

    pci_conf = pci_dev->config;

    pci_conf[PCI_INTERRUPT_PIN] = 1;

    pci_config_set_prog_interface(pci_dev->config, 0x2);

    pci_config_set_class(pci_dev->config, PCI_CLASS_STORAGE_EXPRESS);

    pcie_endpoint_cap_init(&n->parent_obj, 0x80);

    n->num_namespaces = 1;

    n->num_queues = 64;

    n->reg_size = 1 << qemu_fls(0x1004 + 2 * (n->num_queues + 1) * 4);

    n->ns_size = bs_size / (uint64_t)n->num_namespaces;

    n->namespaces = g_malloc0(sizeof(*n->namespaces)*n->num_namespaces);

    n->sq = g_malloc0(sizeof(*n->sq)*n->num_queues);

    n->cq = g_malloc0(sizeof(*n->cq)*n->num_queues);

    memory_region_init_io(&n->iomem, OBJECT(n), &nvme_mmio_ops, n,

                          "nvme", n->reg_size);

    pci_register_bar(&n->parent_obj, 0,

        PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_64,

        &n->iomem);

    msix_init_exclusive_bar(&n->parent_obj, n->num_queues, 4);

    id->vid = cpu_to_le16(pci_get_word(pci_conf + PCI_VENDOR_ID));

    id->ssvid = cpu_to_le16(pci_get_word(pci_conf + PCI_SUBSYSTEM_VENDOR_ID));

    strpadcpy((char *)id->mn, sizeof(id->mn), "QEMU NVMe Ctrl", ' ');

    strpadcpy((char *)id->fr, sizeof(id->fr), "1.0", ' ');

    strpadcpy((char *)id->sn, sizeof(id->sn), n->serial, ' ');

    id->rab = 6;

    id->ieee[0] = 0x00;

    id->ieee[1] = 0x02;

    id->ieee[2] = 0xb3;

    id->oacs = cpu_to_le16(0);

    id->frmw = 7 << 1;

    id->lpa = 1 << 0;

    id->sqes = (0x6 << 4) | 0x6;

    id->cqes = (0x4 << 4) | 0x4;

    id->nn = cpu_to_le32(n->num_namespaces);

    id->psd[0].mp = cpu_to_le16(0x9c4);

    id->psd[0].enlat = cpu_to_le32(0x10);

    id->psd[0].exlat = cpu_to_le32(0x4);

    n->bar.cap = 0;

    NVME_CAP_SET_MQES(n->bar.cap, 0x7ff);

    NVME_CAP_SET_CQR(n->bar.cap, 1);

    NVME_CAP_SET_AMS(n->bar.cap, 1);

    NVME_CAP_SET_TO(n->bar.cap, 0xf);

    NVME_CAP_SET_CSS(n->bar.cap, 1);

    n->bar.vs = 0x00010001;

    n->bar.intmc = n->bar.intms = 0;

    for (i = 0; i < n->num_namespaces; i++) {

        NvmeNamespace *ns = &n->namespaces[i];

        NvmeIdNs *id_ns = &ns->id_ns;

        id_ns->nsfeat = 0;

        id_ns->nlbaf = 0;

        id_ns->flbas = 0;

        id_ns->mc = 0;

        id_ns->dpc = 0;

        id_ns->dps = 0;

        id_ns->lbaf[0].ds = BDRV_SECTOR_BITS;

        id_ns->ncap  = id_ns->nuse = id_ns->nsze =

            cpu_to_le64(n->ns_size >>

                id_ns->lbaf[NVME_ID_NS_FLBAS_INDEX(ns->id_ns.flbas)].ds);

    }

    return 0;

}

static void nvme_exit(PCIDevice *pci_dev)

{

    NvmeCtrl *n = NVME(pci_dev);

    nvme_clear_ctrl(n);

    g_free(n->namespaces);

    g_free(n->cq);

    g_free(n->sq);

    msix_uninit_exclusive_bar(pci_dev);

    memory_region_destroy(&n->iomem);

}

static Property nvme_props[] = {

    DEFINE_BLOCK_PROPERTIES(NvmeCtrl, conf),

    DEFINE_PROP_STRING("serial", NvmeCtrl, serial),

    DEFINE_PROP_END_OF_LIST(),

};

static const VMStateDescription nvme_vmstate = {

    .name = "nvme",

    .unmigratable = 1,

};

static void nvme_class_init(ObjectClass *oc, void *data)

{

    DeviceClass *dc = DEVICE_CLASS(oc);

    PCIDeviceClass *pc = PCI_DEVICE_CLASS(oc);

    pc->init = nvme_init;

    pc->exit = nvme_exit;

    pc->class_id = PCI_CLASS_STORAGE_EXPRESS;

    pc->vendor_id = PCI_VENDOR_ID_INTEL;

    pc->device_id = 0x5845;

    pc->revision = 1;

    pc->is_express = 1;

    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);

    dc->desc = "Non-Volatile Memory Express";

    dc->props = nvme_props;

    dc->vmsd = &nvme_vmstate;

}

static const TypeInfo nvme_info = {

    .name          = "nvme",

    .parent        = TYPE_PCI_DEVICE,

    .instance_size = sizeof(NvmeCtrl),

    .class_init    = nvme_class_init,

};

static void nvme_register_types(void)

{

    type_register_static(&nvme_info);

}

type_init(nvme_register_types)