This is a new protocol driver that exclusively opens a host NVMe
controller through VFIO. It achieves better latency than linux-aio.
nvme:// linux-aio
------------------------------------------------------------------
fio bs=4k iodepth=1 (IOPS) 30014 24009
fio bs=4k iodepth=1 (IOPS) +polling 45148 34689
fio bs=64k iodepth=1 (IOPS) 17801 14954
fio bs=64k iodepth=1 (IOPS) +polling 17970 14564
fio bs=4k iodepth=32 (IOPS) 110637 121480
fio bs=4k iodepth=32 (IOPS) +polling 145533 166878
fio bs=64k iodepth=32 (IOPS) 50525 50596
fio bs=64k iodepth=32 (IOPS) +polling 50482 50534
(host) qemu-img bench -c 8000000 (sec) 15.00 43.13
("+polling" means poll-max-ns=18000 which is a rule of thumb value for
the used NVMe device, otherwise it defaults to 0).
For the rows where linux-aio is faster, a lot of evidence shows that the
io queue is more likely to stay full if the request completions happen
faster, as in the nvme:// case, hence less batch submission and request
merging than linux-aio.
This patch is co-authored by Paolo and me.
Signed-off-by: Fam Zheng <f...@redhat.com>
---
block/Makefile.objs | 1 +
block/nvme.c | 1026 +++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 1027 insertions(+)
create mode 100644 block/nvme.c
diff --git a/block/Makefile.objs b/block/Makefile.objs
index 67a036a..fe975a6 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -11,6 +11,7 @@ block-obj-$(CONFIG_POSIX) += raw-posix.o
block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
block-obj-y += null.o mirror.o commit.o io.o
block-obj-y += throttle-groups.o
+block-obj-y += nvme.o
block-obj-y += nbd.o nbd-client.o sheepdog.o
block-obj-$(CONFIG_LIBISCSI) += iscsi.o
diff --git a/block/nvme.c b/block/nvme.c
new file mode 100644
index 0000000..5c9ffde
--- /dev/null
+++ b/block/nvme.c
@@ -0,0 +1,1026 @@
+/*
+ * NVMe block driver based on vfio
+ *
+ * Copyright 2016 Red Hat, Inc.
+ *
+ * Authors:
+ * Fam Zheng <f...@redhat.com>
+ * Paolo Bonzini <pbonz...@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include <linux/vfio.h>
+#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qstring.h"
+#include "block/block_int.h"
+#include "qemu/error-report.h"
+#include "qemu/vfio-helpers.h"
+
+#define NVME_DEBUG 0
+
+#define DPRINTF(...) \
+ if (NVME_DEBUG) { \
+ printf(__VA_ARGS__); \
+ }
+
+#define NVME_SQ_ENTRY_BYTES 64
+#define NVME_CQ_ENTRY_BYTES 16
+#define NVME_QUEUE_SIZE 128
+
+/* TODO: share definitions with hw/block/nvme.c? */
+enum NvmeAdminCommands {
+ NVME_ADM_CMD_DELETE_SQ = 0x00,
+ NVME_ADM_CMD_CREATE_SQ = 0x01,
+ NVME_ADM_CMD_GET_LOG_PAGE = 0x02,
+ NVME_ADM_CMD_DELETE_CQ = 0x04,
+ NVME_ADM_CMD_CREATE_CQ = 0x05,
+ NVME_ADM_CMD_IDENTIFY = 0x06,
+ NVME_ADM_CMD_ABORT = 0x08,
+ NVME_ADM_CMD_SET_FEATURES = 0x09,
+ NVME_ADM_CMD_GET_FEATURES = 0x0a,
+ NVME_ADM_CMD_ASYNC_EV_REQ = 0x0c,
+ NVME_ADM_CMD_ACTIVATE_FW = 0x10,
+ NVME_ADM_CMD_DOWNLOAD_FW = 0x11,
+ NVME_ADM_CMD_FORMAT_NVM = 0x80,
+ NVME_ADM_CMD_SECURITY_SEND = 0x81,
+ NVME_ADM_CMD_SECURITY_RECV = 0x82,
+};
+
+enum NvmeIoCommands {
+ NVME_CMD_FLUSH = 0x00,
+ NVME_CMD_WRITE = 0x01,
+ NVME_CMD_READ = 0x02,
+ NVME_CMD_WRITE_UNCOR = 0x04,
+ NVME_CMD_COMPARE = 0x05,
+ NVME_CMD_DSM = 0x09,
+};
+
+typedef struct {
+ uint8_t opcode;
+ uint8_t flags;
+ uint16_t cid;
+ uint32_t nsid;
+ uint64_t reserved;
+ uint64_t mptr;
+ uint64_t prp1;
+ uint64_t prp2;
+ uint32_t cdw10;
+ uint32_t cdw11;
+ uint32_t cdw12;
+ uint32_t cdw13;
+ uint32_t cdw14;
+ uint32_t cdw15;
+} QEMU_PACKED NVMeCommand;
+
+typedef struct {
+ uint32_t cmd_specific;
+ uint32_t reserved;
+ uint16_t sq_head;
+ uint16_t sqid;
+ uint16_t cid;
+ uint16_t status;
+} QEMU_PACKED NVMeCompletion;
+
+typedef struct {
+ int32_t head, tail;
+ uint8_t *queue;
+ uint64_t iova;
+ volatile uint32_t *doorbell;
+} NVMeQueue;
+
+typedef struct {
+ BlockCompletionFunc *cb;
+ void *opaque;
+ int cid;
+ void *prp_list_page;
+ uint64_t prp_list_iova;
+} NVMeRequest;
+
+typedef struct {
+ int index;
+ NVMeQueue sq, cq;
+ int cq_phase;
+ uint8_t *prp_list_pages;
+ uint64_t prp_list_base_iova;
+ NVMeRequest reqs[NVME_QUEUE_SIZE];
+ CoQueue wait_queue;
+ bool busy;
+ int need_kick;
+ int inflight;
+} NVMeQueuePair;
+
+typedef volatile struct {
+ uint64_t cap;
+ uint32_t vs;
+ uint32_t intms;
+ uint32_t intmc;
+ uint32_t cc;
+ uint32_t reserved0;
+ uint32_t csts;
+ uint32_t nssr;
+ uint32_t aqa;
+ uint64_t asq;
+ uint64_t acq;
+ uint32_t cmbloc;
+ uint32_t cmbsz;
+ uint8_t reserved1[0xec0];
+ uint8_t cmd_set_specfic[0x100];
+ uint32_t doorbells[];
+} QEMU_PACKED NVMeRegs;
+
+QEMU_BUILD_BUG_ON(offsetof(NVMeRegs, doorbells) != 0x1000);
+
+typedef struct {
+ QEMUVFIOState *vfio;
+ NVMeRegs *regs;
+ /* The submission/completion queue pairs.
+ * [0]: admin queue.
+ * [1..]: io queues.
+ */
+ NVMeQueuePair **queues;
+ int nr_queues;
+ size_t page_size;
+ /* How many uint32_t elements does each doorbell entry take. */
+ size_t doorbell_scale;
+ bool write_cache;
+ EventNotifier event_notifier;
+ uint64_t nsze; /* Namespace size reported by identify command */
+ int nsid; /* The namespace id to read/write data. */
+ uint64_t max_transfer;
+ int plugged;
+ Notifier vfree_notify;
+} BDRVNVMeState;
+
+#define NVME_BLOCK_OPT_DEVICE "device"
+#define NVME_BLOCK_OPT_NAMESPACE "namespace"
+
+static QemuOptsList runtime_opts = {
+ .name = "nvme",
+ .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
+ .desc = {
+ {
+ .name = NVME_BLOCK_OPT_DEVICE,
+ .type = QEMU_OPT_STRING,
+ .help = "NVMe PCI device address",
+ },
+ {
+ .name = NVME_BLOCK_OPT_NAMESPACE,
+ .type = QEMU_OPT_NUMBER,
+ .help = "NVMe namespace",
+ },
+ { /* end of list */ }
+ },
+};
+
+static void nvme_init_queue(BlockDriverState *bs, NVMeQueue *q,
+ int nentries, int entry_bytes, Error **errp)
+{
+ BDRVNVMeState *s = bs->opaque;
+ size_t bytes;
+ int r;
+
+ bytes = ROUND_UP(nentries * entry_bytes, s->page_size);
+ q->head = q->tail = 0;
+ q->queue = qemu_try_blockalign0(bs, bytes);
+
+ if (!q->queue) {
+ error_setg(errp, "Cannot allocate queue");
+ return;
+ }
+ r = qemu_vfio_dma_map(s->vfio, q->queue, bytes, true, &q->iova);
+ if (r) {
+ error_setg(errp, "Cannot map queue");
+ }
+}
+
+static void nvme_free_queue_pair(BlockDriverState *bs, NVMeQueuePair *q)
+{
+ qemu_vfree(q->prp_list_pages);
+ qemu_vfree(q->sq.queue);
+ qemu_vfree(q->cq.queue);
+ g_free(q);
+}
+
+static NVMeQueuePair *nvme_create_queue_pair(BlockDriverState *bs,
+ int idx, int size,
+ Error **errp)
+{
+ int i, r;
+ BDRVNVMeState *s = bs->opaque;
+ Error *local_err = NULL;
+ NVMeQueuePair *q = g_new0(NVMeQueuePair, 1);
+ uint64_t prp_list_iovas[NVME_QUEUE_SIZE];
+
+ q->index = idx;
+ qemu_co_queue_init(&q->wait_queue);
+ q->prp_list_pages = qemu_blockalign0(bs, s->page_size * NVME_QUEUE_SIZE);
+ r = qemu_vfio_dma_map(s->vfio, q->prp_list_pages,
+ s->page_size * NVME_QUEUE_SIZE,
+ false, prp_list_iovas);
+ if (r) {
+ goto fail;
+ }
+ for (i = 0; i < NVME_QUEUE_SIZE; i++) {
+ NVMeRequest *req = &q->reqs[i];
+ req->cid = i + 1;
+ req->prp_list_page = q->prp_list_pages + i * s->page_size;
+ req->prp_list_iova = prp_list_iovas[i];
+ }
+ nvme_init_queue(bs, &q->sq, size, NVME_SQ_ENTRY_BYTES, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ goto fail;
+ }
+ q->sq.doorbell = &s->regs->doorbells[idx * 2 * s->doorbell_scale];
+
+ nvme_init_queue(bs, &q->cq, size, NVME_CQ_ENTRY_BYTES, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ goto fail;
+ }
+ q->cq.doorbell = &s->regs->doorbells[idx * 2 * s->doorbell_scale + 1];
+
+ return q;
+fail:
+ nvme_free_queue_pair(bs, q);
+ return NULL;
+}
+
+static void nvme_kick(BDRVNVMeState *s, NVMeQueuePair *q)
+{
+ if (s->plugged || !q->need_kick) {
+ return;
+ }
+ DPRINTF("nvme kick queue %d\n", q->index);
+ assert(!(q->sq.tail & 0xFF00));
+ /* Fence the write to submission queue entry before notifying the guest. */
+ smp_wmb();
+ *q->sq.doorbell = cpu_to_le32(q->sq.tail);
+ q->inflight += q->need_kick;
+ q->need_kick = 0;
+}
+
+static NVMeRequest *nvme_get_free_req(NVMeQueuePair *q)
+{
+ int i;
+ if (q->inflight + q->need_kick > NVME_QUEUE_SIZE - 2) {
+ /* We have to leave one slot empty as that is the full queue case (head
+ * == tail + 1). */
+ return NULL;
+ }
+ for (i = 0; i < NVME_QUEUE_SIZE; i++) {
+ if (!q->reqs[i].cb) {
+ return &q->reqs[i];
+ }
+ }
+ return NULL;
+}
+
+static inline int nvme_translate_error(const NVMeCompletion *c)
+{
+ if ((le16_to_cpu(c->status) >> 1) & 0xFF) {
+ DPRINTF("NVMe error cmd specific %x sq head %x sqid %x cid %x status
%x\n",
+ c->cmd_specific, c->sq_head, c->sqid, c->cid, c->status);
+ }
+ switch ((le16_to_cpu(c->status) >> 1) & 0xFF) {
+ case 0:
+ return 0;
+ case 1:
+ return -ENOSYS;
+ case 2:
+ return -EINVAL;
+ default:
+ return -EIO;
+ }
+}
+
+static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q)
+{
+ bool progress = false;
+ NVMeRequest *req;
+ NVMeCompletion *c;
+
+ DPRINTF("nvme process completion %d inflight %d\n", q->index, q->inflight);
+ if (q->busy || s->plugged) {
+ DPRINTF("queue busy\n");
+ return false;
+ }
+ q->busy = true;
+ assert(q->inflight >= 0);
+ while (q->inflight) {
+ c = (NVMeCompletion *)&q->cq.queue[q->cq.head * NVME_CQ_ENTRY_BYTES];
+ if (!c->cid || (le16_to_cpu(c->status) & 0x1) == q->cq_phase) {
+ break;
+ }
+ q->cq.head = (q->cq.head + 1) % NVME_QUEUE_SIZE;
+ if (!q->cq.head) {
+ q->cq_phase = !q->cq_phase;
+ }
+ /* XXX: error handling instead of assert as it's from device? */
+ assert(c->cid > 0);
+ assert(c->cid <= NVME_QUEUE_SIZE);
+ DPRINTF("nvme completing command %d\n", c->cid);
+ req = &q->reqs[c->cid - 1];
+ assert(req->cid == c->cid);
+ assert(req->cb);
+ req->cb(req->opaque, nvme_translate_error(c));
+ req->cb = req->opaque = NULL;
+ qemu_co_enter_next(&q->wait_queue);
+ c->cid = 0;
+ q->inflight--;
+ /* Flip Phase Tag bit. */
+ c->status = cpu_to_le16(le16_to_cpu(c->status) ^ 0x1);
+ progress = true;
+ }
+ if (progress) {
+ /* Notify the device so it can post more completions. */
+ smp_mb_release();
+ *q->cq.doorbell = cpu_to_le32(q->cq.head);
+ }
+ q->busy = false;
+ return progress;
+}
+
+static void nvme_submit_command(BDRVNVMeState *s, NVMeQueuePair *q,
+ NVMeRequest *req,
+ NVMeCommand *cmd, BlockCompletionFunc cb,
+ void *opaque)
+{
+ req->cb = cb;
+ req->opaque = opaque;
+ cmd->cid = cpu_to_le32(req->cid);
+ DPRINTF("nvme submit command %d to queue %d\n", req->cid, q->index);
+ memcpy((uint8_t *)q->sq.queue +
+ q->sq.tail * NVME_SQ_ENTRY_BYTES, cmd, sizeof(*cmd));
+ q->sq.tail = (q->sq.tail + 1) % NVME_QUEUE_SIZE;
+ q->need_kick++;
+ nvme_kick(s, q);
+ nvme_process_completion(s, q);
+}
+
+static void nvme_cmd_sync_cb(void *opaque, int ret)
+{
+ int *pret = opaque;
+ *pret = ret;
+}
+
+static int nvme_cmd_sync(BlockDriverState *bs, NVMeQueuePair *q,
+ NVMeCommand *cmd)
+{
+ NVMeRequest *req;
+ BDRVNVMeState *s = bs->opaque;
+ int ret = -EINPROGRESS;
+ req = nvme_get_free_req(q);
+ if (!req) {
+ return -EBUSY;
+ }
+ nvme_submit_command(s, q, req, cmd, nvme_cmd_sync_cb, &ret);
+
+ BDRV_POLL_WHILE(bs, ret == -EINPROGRESS);
+ return ret;
+}
+
+static bool nvme_identify(BlockDriverState *bs, int namespace, Error **errp)
+{
+ BDRVNVMeState *s = bs->opaque;
+ uint8_t *resp;
+ int r;
+ uint64_t iova;
+ NVMeCommand cmd = {
+ .opcode = NVME_ADM_CMD_IDENTIFY,
+ .cdw10 = cpu_to_le32(0x1),
+ };
+
+ resp = qemu_try_blockalign0(bs, 4096);
+ if (!resp) {
+ error_setg(errp, "Cannot allocate buffer for identify response");
+ return false;
+ }
+ r = qemu_vfio_dma_map(s->vfio, resp, 4096, true, &iova);
+ if (r) {
+ error_setg(errp, "Cannot map buffer for DMA");
+ goto fail;
+ }
+ cmd.prp1 = cpu_to_le64(iova);
+
+ if (nvme_cmd_sync(bs, s->queues[0], &cmd)) {
+ error_setg(errp, "Failed to identify controller");
+ goto fail;
+ }
+
+ if (le32_to_cpu(*(uint32_t *)&resp[516]) < namespace) {
+ error_setg(errp, "Invalid namespace");
+ goto fail;
+ }
+ s->write_cache = le32_to_cpu(resp[525]) & 0x1;
+ s->max_transfer = (resp[77] ? 1 << resp[77] : 0) * s->page_size;
+ /* For now the page list buffer per command is one page, to hold at most
+ * s->page_size / sizeof(uint64_t) entries. */
+ s->max_transfer = MIN_NON_ZERO(s->max_transfer,
+ s->page_size / sizeof(uint64_t) * s->page_size);
+
+ memset((char *)resp, 0, 4096);
+
+ cmd.cdw10 = 0;
+ cmd.nsid = namespace;
+ if (nvme_cmd_sync(bs, s->queues[0], &cmd)) {
+ error_setg(errp, "Failed to identify namespace");
+ goto fail;
+ }
+
+ /*qemu_hexdump((const char *)resp, stdout, "NS", 4096);*/
+ s->nsze = le64_to_cpu(*(uint64_t *)&resp[0]);
+
+ qemu_vfree(resp);
+ return true;
+fail:
+ qemu_vfree(resp);
+ return false;
+}
+
+static void nvme_handle_event(EventNotifier *n)
+{
+ int i;
+ BDRVNVMeState *s = container_of(n, BDRVNVMeState, event_notifier);
+
+ DPRINTF("nvme handle event\n");
+ event_notifier_test_and_clear(n);
+ for (i = 0; i < s->nr_queues; i++) {
+ while (nvme_process_completion(s, s->queues[i])) {
+ /* Keep polling until no progress. */
+ }
+ }
+}
+
+static bool nvme_add_io_queue(BlockDriverState *bs, Error **errp)
+{
+ BDRVNVMeState *s = bs->opaque;
+ int n = s->nr_queues;
+ NVMeQueuePair *q;
+ NVMeCommand cmd;
+ int queue_size = NVME_QUEUE_SIZE;
+
+ q = nvme_create_queue_pair(bs, n, queue_size, errp);
+ if (!q) {
+ return false;
+ }
+ cmd = (NVMeCommand) {
+ .opcode = NVME_ADM_CMD_CREATE_CQ,
+ .prp1 = cpu_to_le64(q->cq.iova),
+ .cdw10 = cpu_to_le32(((queue_size - 1) << 16) | (n & 0xFFFF)),
+ .cdw11 = cpu_to_le32(0x3),
+ };
+ if (nvme_cmd_sync(bs, s->queues[0], &cmd)) {
+ error_setg(errp, "Failed to create io queue [%d]", n);
+ nvme_free_queue_pair(bs, q);
+ return false;
+ }
+ cmd = (NVMeCommand) {
+ .opcode = NVME_ADM_CMD_CREATE_SQ,
+ .prp1 = cpu_to_le64(q->sq.iova),
+ .cdw10 = cpu_to_le32(((queue_size - 1) << 16) | (n & 0xFFFF)),
+ .cdw11 = cpu_to_le32(0x1 | (n << 16)),
+ };
+ if (nvme_cmd_sync(bs, s->queues[0], &cmd)) {
+ error_setg(errp, "Failed to create io queue [%d]", n);
+ nvme_free_queue_pair(bs, q);
+ return false;
+ }
+ s->queues = g_renew(NVMeQueuePair *, s->queues, n + 1);
+ s->queues[n] = q;
+ s->nr_queues++;
+ return true;
+}
+
+static bool nvme_poll_cb(void *opaque)
+{
+ int i;
+ EventNotifier *e = opaque;
+ BDRVNVMeState *s = container_of(e, BDRVNVMeState, event_notifier);
+ bool progress = false;
+
+ DPRINTF("nvme poll cb\n");
+ for (i = 0; i < s->nr_queues; i++) {
+ while (nvme_process_completion(s, s->queues[i])) {
+ progress = true;
+ }
+ }
+ return progress;
+}
+
+static void nvme_vfree_cb(Notifier *n, void *p)
+{
+ BDRVNVMeState *s = container_of(n, BDRVNVMeState, vfree_notify);
+ qemu_vfio_dma_unmap(s->vfio, p);
+}
+
+static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
+ Error **errp)
+{
+ BDRVNVMeState *s = bs->opaque;
+ int ret;
+ uint64_t cap;
+ uint64_t timeout_ms;
+ uint64_t deadline, now;
+
+ s->nsid = namespace;
+ ret = event_notifier_init(&s->event_notifier, 0);
+ if (ret) {
+ error_setg(errp, "Failed to init event notifier");
+ return ret;
+ }
+
+ s->vfree_notify.notify = nvme_vfree_cb;
+ qemu_vfree_add_notifier(&s->vfree_notify);
+
+ s->vfio = qemu_vfio_open_pci(device, errp);
+ if (!s->vfio) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ s->regs = qemu_vfio_pci_map_bar(s->vfio, 0, errp);
+ if (!s->regs) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ /* Perform initialize sequence as described in NVMe spec "7.6.1
+ * Initialization". */
+
+ cap = le64_to_cpu(s->regs->cap);
+ if (!(cap & (1ULL << 37))) {
+ error_setg(errp, "Device doesn't support NVMe command set");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ s->page_size = MAX(4096, 1 << (12 + ((cap >> 48) & 0xF)));
+ s->doorbell_scale = (4 << (((cap >> 32) & 0xF))) / sizeof(uint32_t);
+ bs->bl.opt_mem_alignment = s->page_size;
+ timeout_ms = MIN(500 * ((cap >> 24) & 0xFF), 30000);
+
+ /* Reset device to get a clean state. */
+ s->regs->cc = cpu_to_le32(le32_to_cpu(s->regs->cc) & 0xFE);
+ /* Wait for CSTS.RDY = 0. */
+ deadline = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ms *
1000000ULL;
+ while (le32_to_cpu(s->regs->csts) & 0x1) {
+ if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) > deadline) {
+ error_setg(errp, "Timeout while waiting for device to reset (%ld
ms)",
+ timeout_ms);
+ ret = -ETIMEDOUT;
+ goto fail;
+ }
+ }
+
+ /* Set up admin queue. */
+ s->queues = g_new(NVMeQueuePair *, 1);
+ s->nr_queues = 1;
+ s->queues[0] = nvme_create_queue_pair(bs, 0, NVME_QUEUE_SIZE, errp);
+ if (!s->queues[0]) {
+ ret = -EINVAL;
+ goto fail;
+ }
+ QEMU_BUILD_BUG_ON(NVME_QUEUE_SIZE & 0xF000);
+ s->regs->aqa = cpu_to_le32((NVME_QUEUE_SIZE << 16) | NVME_QUEUE_SIZE);
+ s->regs->asq = cpu_to_le64(s->queues[0]->sq.iova);
+ s->regs->acq = cpu_to_le64(s->queues[0]->cq.iova);
+
+ /* After setting up all control registers we can enable device now. */
+ s->regs->cc = cpu_to_le32((ctz32(NVME_CQ_ENTRY_BYTES) << 20) |
+ (ctz32(NVME_SQ_ENTRY_BYTES) << 16) |
+ 0x1);
+ /* Wait for CSTS.RDY = 1. */
+ now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+ deadline = now + timeout_ms * 1000000;
+ while (!(le32_to_cpu(s->regs->csts) & 0x1)) {
+ if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) > deadline) {
+ error_setg(errp, "Timeout while waiting for device to start (%ld
ms)",
+ timeout_ms);
+ ret = -ETIMEDOUT;
+ goto fail_queue;
+ }
+ }
+
+ ret = qemu_vfio_pci_init_irq(s->vfio, &s->event_notifier,
+ VFIO_PCI_MSIX_IRQ_INDEX, errp);
+ if (ret) {
+ goto fail_queue;
+ }
+ aio_set_event_notifier(bdrv_get_aio_context(bs), &s->event_notifier,
+ false, nvme_handle_event, nvme_poll_cb);
+
+ if (!nvme_identify(bs, namespace, errp)) {
+ ret = -EIO;
+ goto fail_handler;
+ }
+
+ /* Set up command queues. */
+ /* XXX: multiple io queues? */
+ if (!nvme_add_io_queue(bs, errp)) {
+ ret = -EIO;
+ goto fail_handler;
+ }
+ return 0;
+
+fail_handler:
+ aio_set_event_notifier(bdrv_get_aio_context(bs), &s->event_notifier,
+ false, NULL, NULL);
+fail_queue:
+ nvme_free_queue_pair(bs, s->queues[0]);
+fail:
+ qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs);
+ qemu_vfio_close(s->vfio);
+ event_notifier_cleanup(&s->event_notifier);
+ return ret;
+}
+
+static void nvme_parse_filename(const char *filename, QDict *options,
+ Error **errp)
+{
+ int pref = strlen("nvme://");
+
+ /* XXX: support namespace in URI like nvme://0000:00:00.0/1 ? */
+ if (strlen(filename) > pref && !strncmp(filename, "nvme://", pref)) {
+ qdict_put(options, NVME_BLOCK_OPT_DEVICE,
+ qstring_from_str(filename + pref));
+ }
+}
+
+static int nvme_file_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ const char *device;
+ QemuOpts *opts;
+ int namespace;
+
+ opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
+ qemu_opts_absorb_qdict(opts, options, &error_abort);
+ device = qemu_opt_get(opts, NVME_BLOCK_OPT_DEVICE);
+ if (!device) {
+ error_setg(errp, "'" NVME_BLOCK_OPT_DEVICE "' option is required");
+ return -EINVAL;
+ }
+
+ namespace = qemu_opt_get_number(opts, NVME_BLOCK_OPT_NAMESPACE, 1);
+ nvme_init(bs, device, namespace, errp);
+
+ qemu_opts_del(opts);
+ return 0;
+}
+
+static void nvme_close(BlockDriverState *bs)
+{
+ int i;
+ BDRVNVMeState *s = bs->opaque;
+
+ for (i = 0; i < s->nr_queues; ++i) {
+ nvme_free_queue_pair(bs, s->queues[i]);
+ }
+ aio_set_event_notifier(bdrv_get_aio_context(bs), &s->event_notifier,
+ false, NULL, NULL);
+ notifier_remove(&s->vfree_notify);
+ qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs);
+ qemu_vfio_close(s->vfio);
+}
+
+static int64_t nvme_getlength(BlockDriverState *bs)
+{
+ BDRVNVMeState *s = bs->opaque;
+
+ return s->nsze << BDRV_SECTOR_BITS;
+}
+
+static inline int nvme_cmd_map_qiov(BlockDriverState *bs, NVMeCommand *cmd,
+ NVMeRequest *req, QEMUIOVector *qiov)
+{
+ BDRVNVMeState *s = bs->opaque;
+ uint64_t *pagelist = req->prp_list_page;
+ int i, r;
+ unsigned int entries = 0;
+
+ assert(qiov->size);
+ assert(QEMU_IS_ALIGNED(qiov->size, s->page_size));
+ assert(qiov->size / s->page_size <= s->page_size / sizeof(uint64_t));
+ for (i = 0; i < qiov->niov; ++i) {
+ r = qemu_vfio_dma_map(s->vfio,
+ qiov->iov[i].iov_base,
+ qiov->iov[i].iov_len,
+ false, &pagelist[entries]);
+ if (r) {
+ return r;
+ }
+
+ entries += qiov->iov[i].iov_len / s->page_size;
+ assert(entries <= s->page_size / sizeof(uint64_t));
+ }
+
+ switch (entries) {
+ case 0:
+ abort();
+ case 1:
+ cmd->prp1 = cpu_to_le64(pagelist[0]);
+ cmd->prp2 = 0;
+ break;
+ case 2:
+ cmd->prp1 = cpu_to_le64(pagelist[0]);
+ cmd->prp2 = cpu_to_le64(pagelist[1]);;
+ break;
+ default:
+ cmd->prp1 = cpu_to_le64(pagelist[0]);
+ cmd->prp2 = cpu_to_le64(req->prp_list_iova);
+ for (i = 0; i < entries - 1; ++i) {
+ pagelist[i] = cpu_to_le64(pagelist[i + 1]);
+ }
+ pagelist[entries] = 0;
+ break;
+ }
+ return 0;
+}
+
+typedef struct {
+ Coroutine *co;
+ int ret;
+ AioContext *ctx;
+} NVMeCoData;
+
+static void nvme_rw_cb_bh(void *opaque)
+{
+ NVMeCoData *data = opaque;
+ qemu_coroutine_enter(data->co);
+}
+
+static void nvme_rw_cb(void *opaque, int ret)
+{
+ NVMeCoData *data = opaque;
+ data->ret = ret;
+ if (!data->co) {
+ /* The rw coroutine hasn't yielded, don't try to enter. */
+ return;
+ }
+ if (qemu_coroutine_self() != data->co) {
+ qemu_coroutine_enter(data->co);
+ } else {
+ aio_bh_schedule_oneshot(data->ctx, nvme_rw_cb_bh, data);
+ }
+}
+
+static coroutine_fn int nvme_co_prw_aligned(BlockDriverState *bs,
+ uint64_t offset, uint64_t bytes,
+ QEMUIOVector *qiov,
+ bool is_write)
+{
+ int r;
+ BDRVNVMeState *s = bs->opaque;
+ NVMeQueuePair *ioq = s->queues[1];
+ NVMeRequest *req;
+ NVMeCommand cmd = {
+ .opcode = is_write ? NVME_CMD_WRITE : NVME_CMD_READ,
+ .nsid = cpu_to_le32(s->nsid),
+ .cdw10 = cpu_to_le32((offset >> BDRV_SECTOR_BITS) & 0xFFFFFFFF),
+ .cdw11 = cpu_to_le32(((offset >> BDRV_SECTOR_BITS) >> 32) &
0xFFFFFFFF),
+ .cdw12 = cpu_to_le32(((bytes >> BDRV_SECTOR_BITS) - 1) & 0xFFFF),
+ };
+ NVMeCoData data = {
+ .ctx = bdrv_get_aio_context(bs),
+ .ret = -EINPROGRESS,
+ };
+
+ DPRINTF(">>> NVMe %s offset %lx bytes %lx qiov[%d]\n",
+ is_write ? "write" : "read",
+ offset, bytes, qiov->niov);
+ assert(s->nr_queues > 1);
+ while (true) {
+ req = nvme_get_free_req(ioq);
+ if (req) {
+ break;
+ }
+ DPRINTF("nvme wait req\n");
+ qemu_co_queue_wait(&ioq->wait_queue);
+ DPRINTF("nvme wait req done\n");
+ }
+
+ r = nvme_cmd_map_qiov(bs, &cmd, req, qiov);
+ if (r) {
+ return r;
+ }
+ nvme_submit_command(s, ioq, req, &cmd, nvme_rw_cb, &data);
+
+ data.co = qemu_coroutine_self();
+ while (data.ret == -EINPROGRESS) {
+ qemu_coroutine_yield();
+ }
+
+ DPRINTF("<<< NVMe %s offset %lx bytes %lx ret %d\n",
+ is_write ? "write" : "read",
+ offset, bytes, data.ret);
+ return data.ret;
+}
+
+static inline bool nvme_qiov_aligned(BlockDriverState *bs,
+ const QEMUIOVector *qiov)
+{
+ int i;
+ BDRVNVMeState *s = bs->opaque;
+
+ for (i = 0; i < qiov->niov; ++i) {
+ if (!QEMU_PTR_IS_ALIGNED(qiov->iov[i].iov_base, s->page_size) ||
+ !QEMU_IS_ALIGNED(qiov->iov[i].iov_len, s->page_size)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+static inline coroutine_fn
+int nvme_co_prw(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
+ QEMUIOVector *qiov, bool is_write)
+{
+ int r;
+ uint8_t *buf;
+ QEMUIOVector local_qiov;
+
+ assert(offset % BDRV_SECTOR_SIZE == 0);
+ assert(bytes % BDRV_SECTOR_SIZE == 0);
+ if (nvme_qiov_aligned(bs, qiov)) {
+ return nvme_co_prw_aligned(bs, offset, bytes, qiov, is_write);
+ }
+ buf = qemu_try_blockalign(bs, bytes);
+
+ if (!buf) {
+ return -ENOMEM;
+ }
+ qemu_iovec_init(&local_qiov, 1);
+ qemu_iovec_add(&local_qiov, buf, bytes);
+ r = nvme_co_prw_aligned(bs, offset, bytes, &local_qiov, is_write);
+ qemu_iovec_destroy(&local_qiov);
+ if (!r) {
+ qemu_iovec_from_buf(qiov, 0, buf, bytes);
+ }
+ qemu_vfree(buf);
+ return r;
+}
+
+static coroutine_fn int nvme_co_preadv(BlockDriverState *bs,
+ uint64_t offset, uint64_t bytes,
+ QEMUIOVector *qiov, int flags)
+{
+ return nvme_co_prw(bs, offset, bytes, qiov, false);
+}
+
+static coroutine_fn int nvme_co_pwritev(BlockDriverState *bs,
+ uint64_t offset, uint64_t bytes,
+ QEMUIOVector *qiov, int flags)
+{
+ return nvme_co_prw(bs, offset, bytes, qiov, true);
+}
+
+static coroutine_fn int nvme_co_flush(BlockDriverState *bs)
+{
+ BDRVNVMeState *s = bs->opaque;
+ NVMeQueuePair *ioq = s->queues[1];
+ NVMeRequest *req;
+ NVMeCommand cmd = {
+ .opcode = NVME_CMD_FLUSH,
+ .nsid = cpu_to_le32(s->nsid),
+ };
+ NVMeCoData data = {
+ .ctx = bdrv_get_aio_context(bs),
+ .ret = -EINPROGRESS,
+ };
+
+ assert(s->nr_queues > 1);
+ while (true) {
+ req = nvme_get_free_req(ioq);
+ if (req) {
+ break;
+ }
+ qemu_co_queue_wait(&ioq->wait_queue);
+ }
+
+ nvme_submit_command(s, ioq, req, &cmd, nvme_rw_cb, &data);
+
+ data.co = qemu_coroutine_self();
+ if (data.ret == -EINPROGRESS) {
+ qemu_coroutine_yield();
+ }
+
+ return data.ret;
+}
+
+
+static int nvme_reopen_prepare(BDRVReopenState *reopen_state,
+ BlockReopenQueue *queue, Error **errp)
+{
+ return 0;
+}
+
+static int64_t coroutine_fn nvme_co_get_block_status(BlockDriverState *bs,
+ int64_t sector_num,
+ int nb_sectors, int *pnum,
+ BlockDriverState **file)
+{
+ *pnum = nb_sectors;
+ *file = bs;
+
+ return BDRV_BLOCK_OFFSET_VALID | (sector_num << BDRV_SECTOR_BITS);
+}
+
+static void nvme_refresh_filename(BlockDriverState *bs, QDict *opts)
+{
+ QINCREF(opts);
+ qdict_del(opts, "filename");
+
+ if (!qdict_size(opts)) {
+ snprintf(bs->exact_filename, sizeof(bs->exact_filename), "%s://",
+ bs->drv->format_name);
+ }
+
+ qdict_put(opts, "driver", qstring_from_str(bs->drv->format_name));
+ bs->full_open_options = opts;
+}
+
+static void nvme_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+ BDRVNVMeState *s = bs->opaque;
+
+ /* XXX: other fields from identify command/controller capacity? */
+ bs->bl.opt_mem_alignment = s->page_size;
+ /* XXX: are there other limits? */
+ bs->bl.request_alignment = s->page_size;
+ bs->bl.max_transfer = s->max_transfer;
+}
+
+static void nvme_detach_aio_context(BlockDriverState *bs)
+{
+ BDRVNVMeState *s = bs->opaque;
+
+ aio_set_event_notifier(bdrv_get_aio_context(bs), &s->event_notifier,
+ false, NULL, NULL);
+}
+
+static void nvme_attach_aio_context(BlockDriverState *bs,
+ AioContext *new_context)
+{
+ BDRVNVMeState *s = bs->opaque;
+
+ aio_set_event_notifier(new_context, &s->event_notifier,
+ false, nvme_handle_event, nvme_poll_cb);
+}
+
+static void nvme_aio_plug(BlockDriverState *bs)
+{
+ BDRVNVMeState *s = bs->opaque;
+ s->plugged++;
+}
+
+static void nvme_aio_unplug(BlockDriverState *bs)
+{
+ int i;
+ BDRVNVMeState *s = bs->opaque;
+ assert(s->plugged);
+ if (!--s->plugged) {
+ for (i = 1; i < s->nr_queues; i++) {
+ nvme_kick(s, s->queues[i]);
+ nvme_process_completion(s, s->queues[i]);
+ }
+ }
+}
+
+static BlockDriver bdrv_nvme = {
+ .format_name = "nvme",
+ .protocol_name = "nvme",
+ .instance_size = sizeof(BDRVNVMeState),
+
+ .bdrv_parse_filename = nvme_parse_filename,
+ .bdrv_file_open = nvme_file_open,
+ .bdrv_close = nvme_close,
+ .bdrv_getlength = nvme_getlength,
+
+ .bdrv_co_preadv = nvme_co_preadv,
+ .bdrv_co_pwritev = nvme_co_pwritev,
+ .bdrv_co_flush_to_disk = nvme_co_flush,
+ .bdrv_reopen_prepare = nvme_reopen_prepare,
+
+ .bdrv_co_get_block_status = nvme_co_get_block_status,
+
+ .bdrv_refresh_filename = nvme_refresh_filename,
+ .bdrv_refresh_limits = nvme_refresh_limits,
+
+ .bdrv_detach_aio_context = nvme_detach_aio_context,
+ .bdrv_attach_aio_context = nvme_attach_aio_context,
+
+ .bdrv_io_plug = nvme_aio_plug,
+ .bdrv_io_unplug = nvme_aio_unplug,
+};
+
+static void bdrv_nvme_init(void)
+{
+ bdrv_register(&bdrv_nvme);
+}
+
+block_init(bdrv_nvme_init);
--
2.9.3
