nvmet: add a generic NVMe target

This patch introduces a implementation of NVMe subsystems,
controllers and discovery service which allows to export
NVMe namespaces across fabrics such as Ethernet, FC etc.

The implementation conforms to the NVMe 1.2.1 specification
and interoperates with NVMe over fabrics host implementations.

Configuration works using configfs, and is best performed using
the nvmetcli tool from http://git.infradead.org/users/hch/nvmetcli.git,
which also has a detailed explanation of the required steps in the
README file.

Signed-off-by: Armen Baloyan <armenx.baloyan@intel.com>
Signed-off-by: Anthony Knapp <anthony.j.knapp@intel.com>
Signed-off-by: Jay Freyensee <james.p.freyensee@intel.com>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 465 insertions, 0 deletions

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
new file mode 100644
index 000000000000..2fac17a5ad53
--- /dev/null
+++ b/drivers/nvme/target/admin-cmd.c
@@ -0,0 +1,465 @@
+/*
+ * NVMe admin command implementation.
+ * Copyright (c) 2015-2016 HGST, a Western Digital Company.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/random.h>
+#include <generated/utsrelease.h>
+#include "nvmet.h"
+
+u32 nvmet_get_log_page_len(struct nvme_command *cmd)
+{
+	u32 len = le16_to_cpu(cmd->get_log_page.numdu);
+
+	len <<= 16;
+	len += le16_to_cpu(cmd->get_log_page.numdl);
+	/* NUMD is a 0's based value */
+	len += 1;
+	len *= sizeof(u32);
+
+	return len;
+}
+
+static void nvmet_execute_get_log_page(struct nvmet_req *req)
+{
+	size_t data_len = nvmet_get_log_page_len(req->cmd);
+	void *buf;
+	u16 status = 0;
+
+	buf = kzalloc(data_len, GFP_KERNEL);
+	if (!buf) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	switch (req->cmd->get_log_page.lid) {
+	case 0x01:
+		/*
+		 * We currently never set the More bit in the status field,
+		 * so all error log entries are invalid and can be zeroed out.
+		 * This is called a minum viable implementation (TM) of this
+		 * mandatory log page.
+		 */
+		break;
+	case 0x02:
+		/*
+		 * XXX: fill out actual smart log
+		 *
+		 * We might have a hard time coming up with useful values for
+		 * many of the fields, and even when we have useful data
+		 * available (e.g. units or commands read/written) those aren't
+		 * persistent over power loss.
+		 */
+		break;
+	case 0x03:
+		/*
+		 * We only support a single firmware slot which always is
+		 * active, so we can zero out the whole firmware slot log and
+		 * still claim to fully implement this mandatory log page.
+		 */
+		break;
+	default:
+		BUG();
+	}
+
+	status = nvmet_copy_to_sgl(req, 0, buf, data_len);
+
+	kfree(buf);
+out:
+	nvmet_req_complete(req, status);
+}
+
+static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
+{
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+	struct nvme_id_ctrl *id;
+	u64 serial;
+	u16 status = 0;
+
+	id = kzalloc(sizeof(*id), GFP_KERNEL);
+	if (!id) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	/* XXX: figure out how to assign real vendors IDs. */
+	id->vid = 0;
+	id->ssvid = 0;
+
+	/* generate a random serial number as our controllers are ephemeral: */
+	get_random_bytes(&serial, sizeof(serial));
+	memset(id->sn, ' ', sizeof(id->sn));
+	snprintf(id->sn, sizeof(id->sn), "%llx", serial);
+
+	memset(id->mn, ' ', sizeof(id->mn));
+	strncpy((char *)id->mn, "Linux", sizeof(id->mn));
+
+	memset(id->fr, ' ', sizeof(id->fr));
+	strncpy((char *)id->fr, UTS_RELEASE, sizeof(id->fr));
+
+	id->rab = 6;
+
+	/*
+	 * XXX: figure out how we can assign a IEEE OUI, but until then
+	 * the safest is to leave it as zeroes.
+	 */
+
+	/* we support multiple ports and multiples hosts: */
+	id->mic = (1 << 0) | (1 << 1);
+
+	/* no limit on data transfer sizes for now */
+	id->mdts = 0;
+	id->cntlid = cpu_to_le16(ctrl->cntlid);
+	id->ver = cpu_to_le32(ctrl->subsys->ver);
+
+	/* XXX: figure out what to do about RTD3R/RTD3 */
+	id->oaes = cpu_to_le32(1 << 8);
+	id->ctratt = cpu_to_le32(1 << 0);
+
+	id->oacs = 0;
+
+	/*
+	 * We don't really have a practical limit on the number of abort
+	 * comands.  But we don't do anything useful for abort either, so
+	 * no point in allowing more abort commands than the spec requires.
+	 */
+	id->acl = 3;
+
+	id->aerl = NVMET_ASYNC_EVENTS - 1;
+
+	/* first slot is read-only, only one slot supported */
+	id->frmw = (1 << 0) | (1 << 1);
+	id->lpa = (1 << 0) | (1 << 2);
+	id->elpe = NVMET_ERROR_LOG_SLOTS - 1;
+	id->npss = 0;
+
+	/* We support keep-alive timeout in granularity of seconds */
+	id->kas = cpu_to_le16(NVMET_KAS);
+
+	id->sqes = (0x6 << 4) | 0x6;
+	id->cqes = (0x4 << 4) | 0x4;
+
+	/* no enforcement soft-limit for maxcmd - pick arbitrary high value */
+	id->maxcmd = cpu_to_le16(NVMET_MAX_CMD);
+
+	id->nn = cpu_to_le32(ctrl->subsys->max_nsid);
+	id->oncs = cpu_to_le16(NVME_CTRL_ONCS_DSM);
+
+	/* XXX: don't report vwc if the underlying device is write through */
+	id->vwc = NVME_CTRL_VWC_PRESENT;
+
+	/*
+	 * We can't support atomic writes bigger than a LBA without support
+	 * from the backend device.
+	 */
+	id->awun = 0;
+	id->awupf = 0;
+
+	id->sgls = cpu_to_le32(1 << 0);	/* we always support SGLs */
+	if (ctrl->ops->has_keyed_sgls)
+		id->sgls |= cpu_to_le32(1 << 2);
+	if (ctrl->ops->sqe_inline_size)
+		id->sgls |= cpu_to_le32(1 << 20);
+
+	strcpy(id->subnqn, ctrl->subsys->subsysnqn);
+
+	/* Max command capsule size is sqe + single page of in-capsule data */
+	id->ioccsz = cpu_to_le32((sizeof(struct nvme_command) +
+				  ctrl->ops->sqe_inline_size) / 16);
+	/* Max response capsule size is cqe */
+	id->iorcsz = cpu_to_le32(sizeof(struct nvme_completion) / 16);
+
+	id->msdbd = ctrl->ops->msdbd;
+
+	/*
+	 * Meh, we don't really support any power state.  Fake up the same
+	 * values that qemu does.
+	 */
+	id->psd[0].max_power = cpu_to_le16(0x9c4);
+	id->psd[0].entry_lat = cpu_to_le32(0x10);
+	id->psd[0].exit_lat = cpu_to_le32(0x4);
+
+	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
+
+	kfree(id);
+out:
+	nvmet_req_complete(req, status);
+}
+
+static void nvmet_execute_identify_ns(struct nvmet_req *req)
+{
+	struct nvmet_ns *ns;
+	struct nvme_id_ns *id;
+	u16 status = 0;
+
+	ns = nvmet_find_namespace(req->sq->ctrl, req->cmd->identify.nsid);
+	if (!ns) {
+		status = NVME_SC_INVALID_NS | NVME_SC_DNR;
+		goto out;
+	}
+
+	id = kzalloc(sizeof(*id), GFP_KERNEL);
+	if (!id) {
+		status = NVME_SC_INTERNAL;
+		goto out_put_ns;
+	}
+
+	/*
+	 * nuse = ncap = nsze isn't aways true, but we have no way to find
+	 * that out from the underlying device.
+	 */
+	id->ncap = id->nuse = id->nsze =
+		cpu_to_le64(ns->size >> ns->blksize_shift);
+
+	/*
+	 * We just provide a single LBA format that matches what the
+	 * underlying device reports.
+	 */
+	id->nlbaf = 0;
+	id->flbas = 0;
+
+	/*
+	 * Our namespace might always be shared.  Not just with other
+	 * controllers, but also with any other user of the block device.
+	 */
+	id->nmic = (1 << 0);
+
+	memcpy(&id->nguid, &ns->nguid, sizeof(uuid_le));
+
+	id->lbaf[0].ds = ns->blksize_shift;
+
+	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
+
+	kfree(id);
+out_put_ns:
+	nvmet_put_namespace(ns);
+out:
+	nvmet_req_complete(req, status);
+}
+
+static void nvmet_execute_identify_nslist(struct nvmet_req *req)
+{
+	static const int buf_size = 4096;
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+	struct nvmet_ns *ns;
+	u32 min_nsid = le32_to_cpu(req->cmd->identify.nsid);
+	__le32 *list;
+	u16 status = 0;
+	int i = 0;
+
+	list = kzalloc(buf_size, GFP_KERNEL);
+	if (!list) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ns, &ctrl->subsys->namespaces, dev_link) {
+		if (ns->nsid <= min_nsid)
+			continue;
+		list[i++] = cpu_to_le32(ns->nsid);
+		if (i == buf_size / sizeof(__le32))
+			break;
+	}
+	rcu_read_unlock();
+
+	status = nvmet_copy_to_sgl(req, 0, list, buf_size);
+
+	kfree(list);
+out:
+	nvmet_req_complete(req, status);
+}
+
+/*
+ * A "mimimum viable" abort implementation: the command is mandatory in the
+ * spec, but we are not required to do any useful work.  We couldn't really
+ * do a useful abort, so don't bother even with waiting for the command
+ * to be exectuted and return immediately telling the command to abort
+ * wasn't found.
+ */
+static void nvmet_execute_abort(struct nvmet_req *req)
+{
+	nvmet_set_result(req, 1);
+	nvmet_req_complete(req, 0);
+}
+
+static void nvmet_execute_set_features(struct nvmet_req *req)
+{
+	struct nvmet_subsys *subsys = req->sq->ctrl->subsys;
+	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10[0]);
+	u64 val;
+	u32 val32;
+	u16 status = 0;
+
+	switch (cdw10 & 0xf) {
+	case NVME_FEAT_NUM_QUEUES:
+		nvmet_set_result(req,
+			(subsys->max_qid - 1) | ((subsys->max_qid - 1) << 16));
+		break;
+	case NVME_FEAT_KATO:
+		val = le64_to_cpu(req->cmd->prop_set.value);
+		val32 = val & 0xffff;
+		req->sq->ctrl->kato = DIV_ROUND_UP(val32, 1000);
+		nvmet_set_result(req, req->sq->ctrl->kato);
+		break;
+	default:
+		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+		break;
+	}
+
+	nvmet_req_complete(req, status);
+}
+
+static void nvmet_execute_get_features(struct nvmet_req *req)
+{
+	struct nvmet_subsys *subsys = req->sq->ctrl->subsys;
+	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10[0]);
+	u16 status = 0;
+
+	switch (cdw10 & 0xf) {
+	/*
+	 * These features are mandatory in the spec, but we don't
+	 * have a useful way to implement them.  We'll eventually
+	 * need to come up with some fake values for these.
+	 */
+#if 0
+	case NVME_FEAT_ARBITRATION:
+		break;
+	case NVME_FEAT_POWER_MGMT:
+		break;
+	case NVME_FEAT_TEMP_THRESH:
+		break;
+	case NVME_FEAT_ERR_RECOVERY:
+		break;
+	case NVME_FEAT_IRQ_COALESCE:
+		break;
+	case NVME_FEAT_IRQ_CONFIG:
+		break;
+	case NVME_FEAT_WRITE_ATOMIC:
+		break;
+	case NVME_FEAT_ASYNC_EVENT:
+		break;
+#endif
+	case NVME_FEAT_VOLATILE_WC:
+		nvmet_set_result(req, 1);
+		break;
+	case NVME_FEAT_NUM_QUEUES:
+		nvmet_set_result(req,
+			(subsys->max_qid-1) | ((subsys->max_qid-1) << 16));
+		break;
+	case NVME_FEAT_KATO:
+		nvmet_set_result(req, req->sq->ctrl->kato * 1000);
+		break;
+	default:
+		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+		break;
+	}
+
+	nvmet_req_complete(req, status);
+}
+
+static void nvmet_execute_async_event(struct nvmet_req *req)
+{
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+
+	mutex_lock(&ctrl->lock);
+	if (ctrl->nr_async_event_cmds >= NVMET_ASYNC_EVENTS) {
+		mutex_unlock(&ctrl->lock);
+		nvmet_req_complete(req, NVME_SC_ASYNC_LIMIT | NVME_SC_DNR);
+		return;
+	}
+	ctrl->async_event_cmds[ctrl->nr_async_event_cmds++] = req;
+	mutex_unlock(&ctrl->lock);
+
+	schedule_work(&ctrl->async_event_work);
+}
+
+static void nvmet_execute_keep_alive(struct nvmet_req *req)
+{
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+
+	pr_debug("ctrl %d update keep-alive timer for %d secs\n",
+		ctrl->cntlid, ctrl->kato);
+
+	mod_delayed_work(system_wq, &ctrl->ka_work, ctrl->kato * HZ);
+	nvmet_req_complete(req, 0);
+}
+
+int nvmet_parse_admin_cmd(struct nvmet_req *req)
+{
+	struct nvme_command *cmd = req->cmd;
+
+	req->ns = NULL;
+
+	if (unlikely(!(req->sq->ctrl->cc & NVME_CC_ENABLE))) {
+		pr_err("nvmet: got admin cmd %d while CC.EN == 0\n",
+				cmd->common.opcode);
+		return NVME_SC_CMD_SEQ_ERROR | NVME_SC_DNR;
+	}
+	if (unlikely(!(req->sq->ctrl->csts & NVME_CSTS_RDY))) {
+		pr_err("nvmet: got admin cmd %d while CSTS.RDY == 0\n",
+				cmd->common.opcode);
+		return NVME_SC_CMD_SEQ_ERROR | NVME_SC_DNR;
+	}
+
+	switch (cmd->common.opcode) {
+	case nvme_admin_get_log_page:
+		req->data_len = nvmet_get_log_page_len(cmd);
+
+		switch (cmd->get_log_page.lid) {
+		case 0x01:
+		case 0x02:
+		case 0x03:
+			req->execute = nvmet_execute_get_log_page;
+			return 0;
+		}
+		break;
+	case nvme_admin_identify:
+		req->data_len = 4096;
+		switch (le32_to_cpu(cmd->identify.cns)) {
+		case 0x00:
+			req->execute = nvmet_execute_identify_ns;
+			return 0;
+		case 0x01:
+			req->execute = nvmet_execute_identify_ctrl;
+			return 0;
+		case 0x02:
+			req->execute = nvmet_execute_identify_nslist;
+			return 0;
+		}
+		break;
+	case nvme_admin_abort_cmd:
+		req->execute = nvmet_execute_abort;
+		req->data_len = 0;
+		return 0;
+	case nvme_admin_set_features:
+		req->execute = nvmet_execute_set_features;
+		req->data_len = 0;
+		return 0;
+	case nvme_admin_get_features:
+		req->execute = nvmet_execute_get_features;
+		req->data_len = 0;
+		return 0;
+	case nvme_admin_async_event:
+		req->execute = nvmet_execute_async_event;
+		req->data_len = 0;
+		return 0;
+	case nvme_admin_keep_alive:
+		req->execute = nvmet_execute_keep_alive;
+		req->data_len = 0;
+		return 0;
+	}
+
+	pr_err("nvmet: unhandled cmd %d\n", cmd->common.opcode);
+	return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+}