1 files changed, 458 insertions, 0 deletions
diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
new file mode 100644
index 000000000000..b9727553ab30
--- /dev/null
+++ b/drivers/nvme/target/passthru.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe Over Fabrics Target Passthrough command implementation.
+ *
+ * Copyright (c) 2017-2018 Western Digital Corporation or its
+ * affiliates.
+ * Copyright (c) 2019-2020, Eideticom Inc.
+ *
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+
+#include "../host/nvme.h"
+#include "nvmet.h"
+
+MODULE_IMPORT_NS(NVME_TARGET_PASSTHRU);
+
+static u16 nvmet_passthru_override_id_ctrl(struct nvmet_req *req)
+{
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+	struct nvme_ctrl *pctrl = ctrl->subsys->passthru_ctrl;
+	u16 status = NVME_SC_SUCCESS;
+	struct nvme_id_ctrl *id;
+	u32 max_hw_sectors;
+	int page_shift;
+
+	id = kzalloc(sizeof(*id), GFP_KERNEL);
+	if (!id)
+		return NVME_SC_INTERNAL;
+
+	status = nvmet_copy_from_sgl(req, 0, id, sizeof(*id));
+	if (status)
+		goto out_free;
+
+	id->cntlid = cpu_to_le16(ctrl->cntlid);
+	id->ver = cpu_to_le32(ctrl->subsys->ver);
+
+	/*
+	 * The passthru NVMe driver may have a limit on the number of segments
+	 * which depends on the host's memory fragementation. To solve this,
+	 * ensure mdts is limited to the pages equal to the number of segments.
+	 */
+	max_hw_sectors = min_not_zero(pctrl->max_segments << (PAGE_SHIFT - 9),
+				      pctrl->max_hw_sectors);
+
+	page_shift = NVME_CAP_MPSMIN(ctrl->cap) + 12;
+
+	id->mdts = ilog2(max_hw_sectors) + 9 - page_shift;
+
+	id->acl = 3;
+	/*
+	 * We export aerl limit for the fabrics controller, update this when
+	 * passthru based aerl support is added.
+	 */
+	id->aerl = NVMET_ASYNC_EVENTS - 1;
+
+	/* emulate kas as most of the PCIe ctrl don't have a support for kas */
+	id->kas = cpu_to_le16(NVMET_KAS);
+
+	/* don't support host memory buffer */
+	id->hmpre = 0;
+	id->hmmin = 0;
+
+	id->sqes = min_t(__u8, ((0x6 << 4) | 0x6), id->sqes);
+	id->cqes = min_t(__u8, ((0x4 << 4) | 0x4), id->cqes);
+	id->maxcmd = cpu_to_le16(NVMET_MAX_CMD);
+
+	/* don't support fuse commands */
+	id->fuses = 0;
+
+	id->sgls = cpu_to_le32(1 << 0); /* we always support SGLs */
+	if (ctrl->ops->flags & NVMF_KEYED_SGLS)
+		id->sgls |= cpu_to_le32(1 << 2);
+	if (req->port->inline_data_size)
+		id->sgls |= cpu_to_le32(1 << 20);
+
+	/*
+	 * When passsthru controller is setup using nvme-loop transport it will
+	 * export the passthru ctrl subsysnqn (PCIe NVMe ctrl) and will fail in
+	 * the nvme/host/core.c in the nvme_init_subsystem()->nvme_active_ctrl()
+	 * code path with duplicate ctr subsynqn. In order to prevent that we
+	 * mask the passthru-ctrl subsysnqn with the target ctrl subsysnqn.
+	 */
+	memcpy(id->subnqn, ctrl->subsysnqn, sizeof(id->subnqn));
+
+	/* use fabric id-ctrl values */
+	id->ioccsz = cpu_to_le32((sizeof(struct nvme_command) +
+				req->port->inline_data_size) / 16);
+	id->iorcsz = cpu_to_le32(sizeof(struct nvme_completion) / 16);
+
+	id->msdbd = ctrl->ops->msdbd;
+
+	/* Support multipath connections with fabrics */
+	id->cmic |= 1 << 1;
+
+	/* Disable reservations, see nvmet_parse_passthru_io_cmd() */
+	id->oncs &= cpu_to_le16(~NVME_CTRL_ONCS_RESERVATIONS);
+
+	status = nvmet_copy_to_sgl(req, 0, id, sizeof(struct nvme_id_ctrl));
+
+out_free:
+	kfree(id);
+	return status;
+}
+
+static u16 nvmet_passthru_override_id_ns(struct nvmet_req *req)
+{
+	u16 status = NVME_SC_SUCCESS;
+	struct nvme_id_ns *id;
+	int i;
+
+	id = kzalloc(sizeof(*id), GFP_KERNEL);
+	if (!id)
+		return NVME_SC_INTERNAL;
+
+	status = nvmet_copy_from_sgl(req, 0, id, sizeof(struct nvme_id_ns));
+	if (status)
+		goto out_free;
+
+	for (i = 0; i < (id->nlbaf + 1); i++)
+		if (id->lbaf[i].ms)
+			memset(&id->lbaf[i], 0, sizeof(id->lbaf[i]));
+
+	id->flbas = id->flbas & ~(1 << 4);
+
+	/*
+	 * Presently the NVMEof target code does not support sending
+	 * metadata, so we must disable it here. This should be updated
+	 * once target starts supporting metadata.
+	 */
+	id->mc = 0;
+
+	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
+
+out_free:
+	kfree(id);
+	return status;
+}
+
+static void nvmet_passthru_execute_cmd_work(struct work_struct *w)
+{
+	struct nvmet_req *req = container_of(w, struct nvmet_req, p.work);
+	struct request *rq = req->p.rq;
+	u16 status;
+
+	nvme_execute_passthru_rq(rq);
+
+	status = nvme_req(rq)->status;
+	if (status == NVME_SC_SUCCESS &&
+	    req->cmd->common.opcode == nvme_admin_identify) {
+		switch (req->cmd->identify.cns) {
+		case NVME_ID_CNS_CTRL:
+			nvmet_passthru_override_id_ctrl(req);
+			break;
+		case NVME_ID_CNS_NS:
+			nvmet_passthru_override_id_ns(req);
+			break;
+		}
+	}
+
+	req->cqe->result = nvme_req(rq)->result;
+	nvmet_req_complete(req, status);
+	blk_put_request(rq);
+}
+
+static void nvmet_passthru_req_done(struct request *rq,
+				    blk_status_t blk_status)
+{
+	struct nvmet_req *req = rq->end_io_data;
+
+	req->cqe->result = nvme_req(rq)->result;
+	nvmet_req_complete(req, nvme_req(rq)->status);
+	blk_put_request(rq);
+}
+
+static int nvmet_passthru_map_sg(struct nvmet_req *req, struct request *rq)
+{
+	int sg_cnt = req->sg_cnt;
+	struct scatterlist *sg;
+	int op_flags = 0;
+	struct bio *bio;
+	int i, ret;
+
+	if (req->cmd->common.opcode == nvme_cmd_flush)
+		op_flags = REQ_FUA;
+	else if (nvme_is_write(req->cmd))
+		op_flags = REQ_SYNC | REQ_IDLE;
+
+	bio = bio_alloc(GFP_KERNEL, min(sg_cnt, BIO_MAX_PAGES));
+	bio->bi_end_io = bio_put;
+	bio->bi_opf = req_op(rq) | op_flags;
+
+	for_each_sg(req->sg, sg, req->sg_cnt, i) {
+		if (bio_add_pc_page(rq->q, bio, sg_page(sg), sg->length,
+				    sg->offset) < sg->length) {
+			bio_put(bio);
+			return -EINVAL;
+		}
+		sg_cnt--;
+	}
+
+	ret = blk_rq_append_bio(rq, &bio);
+	if (unlikely(ret)) {
+		bio_put(bio);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void nvmet_passthru_execute_cmd(struct nvmet_req *req)
+{
+	struct nvme_ctrl *ctrl = nvmet_req_passthru_ctrl(req);
+	struct request_queue *q = ctrl->admin_q;
+	struct nvme_ns *ns = NULL;
+	struct request *rq = NULL;
+	u32 effects;
+	u16 status;
+	int ret;
+
+	if (likely(req->sq->qid != 0)) {
+		u32 nsid = le32_to_cpu(req->cmd->common.nsid);
+
+		ns = nvme_find_get_ns(ctrl, nsid);
+		if (unlikely(!ns)) {
+			pr_err("failed to get passthru ns nsid:%u\n", nsid);
+			status = NVME_SC_INVALID_NS | NVME_SC_DNR;
+			goto fail_out;
+		}
+
+		q = ns->queue;
+	}
+
+	rq = nvme_alloc_request(q, req->cmd, BLK_MQ_REQ_NOWAIT, NVME_QID_ANY);
+	if (IS_ERR(rq)) {
+		rq = NULL;
+		status = NVME_SC_INTERNAL;
+		goto fail_out;
+	}
+
+	if (req->sg_cnt) {
+		ret = nvmet_passthru_map_sg(req, rq);
+		if (unlikely(ret)) {
+			status = NVME_SC_INTERNAL;
+			goto fail_out;
+		}
+	}
+
+	/*
+	 * If there are effects for the command we are about to execute, or
+	 * an end_req function we need to use nvme_execute_passthru_rq()
+	 * synchronously in a work item seeing the end_req function and
+	 * nvme_passthru_end() can't be called in the request done callback
+	 * which is typically in interrupt context.
+	 */
+	effects = nvme_command_effects(ctrl, ns, req->cmd->common.opcode);
+	if (req->p.use_workqueue || effects) {
+		INIT_WORK(&req->p.work, nvmet_passthru_execute_cmd_work);
+		req->p.rq = rq;
+		schedule_work(&req->p.work);
+	} else {
+		rq->end_io_data = req;
+		blk_execute_rq_nowait(rq->q, ns ? ns->disk : NULL, rq, 0,
+				      nvmet_passthru_req_done);
+	}
+
+	if (ns)
+		nvme_put_ns(ns);
+
+	return;
+
+fail_out:
+	if (ns)
+		nvme_put_ns(ns);
+	nvmet_req_complete(req, status);
+	blk_put_request(rq);
+}
+
+/*
+ * We need to emulate set host behaviour to ensure that any requested
+ * behaviour of the target's host matches the requested behaviour
+ * of the device's host and fail otherwise.
+ */
+static void nvmet_passthru_set_host_behaviour(struct nvmet_req *req)
+{
+	struct nvme_ctrl *ctrl = nvmet_req_passthru_ctrl(req);
+	struct nvme_feat_host_behavior *host;
+	u16 status = NVME_SC_INTERNAL;
+	int ret;
+
+	host = kzalloc(sizeof(*host) * 2, GFP_KERNEL);
+	if (!host)
+		goto out_complete_req;
+
+	ret = nvme_get_features(ctrl, NVME_FEAT_HOST_BEHAVIOR, 0,
+				host, sizeof(*host), NULL);
+	if (ret)
+		goto out_free_host;
+
+	status = nvmet_copy_from_sgl(req, 0, &host[1], sizeof(*host));
+	if (status)
+		goto out_free_host;
+
+	if (memcmp(&host[0], &host[1], sizeof(host[0]))) {
+		pr_warn("target host has requested different behaviour from the local host\n");
+		status = NVME_SC_INTERNAL;
+	}
+
+out_free_host:
+	kfree(host);
+out_complete_req:
+	nvmet_req_complete(req, status);
+}
+
+static u16 nvmet_setup_passthru_command(struct nvmet_req *req)
+{
+	req->p.use_workqueue = false;
+	req->execute = nvmet_passthru_execute_cmd;
+	return NVME_SC_SUCCESS;
+}
+
+u16 nvmet_parse_passthru_io_cmd(struct nvmet_req *req)
+{
+	switch (req->cmd->common.opcode) {
+	case nvme_cmd_resv_register:
+	case nvme_cmd_resv_report:
+	case nvme_cmd_resv_acquire:
+	case nvme_cmd_resv_release:
+		/*
+		 * Reservations cannot be supported properly because the
+		 * underlying device has no way of differentiating different
+		 * hosts that connect via fabrics. This could potentially be
+		 * emulated in the future if regular targets grow support for
+		 * this feature.
+		 */
+		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+	}
+
+	return nvmet_setup_passthru_command(req);
+}
+
+/*
+ * Only features that are emulated or specifically allowed in the list  are
+ * passed down to the controller. This function implements the allow list for
+ * both get and set features.
+ */
+static u16 nvmet_passthru_get_set_features(struct nvmet_req *req)
+{
+	switch (le32_to_cpu(req->cmd->features.fid)) {
+	case NVME_FEAT_ARBITRATION:
+	case NVME_FEAT_POWER_MGMT:
+	case NVME_FEAT_LBA_RANGE:
+	case NVME_FEAT_TEMP_THRESH:
+	case NVME_FEAT_ERR_RECOVERY:
+	case NVME_FEAT_VOLATILE_WC:
+	case NVME_FEAT_WRITE_ATOMIC:
+	case NVME_FEAT_AUTO_PST:
+	case NVME_FEAT_TIMESTAMP:
+	case NVME_FEAT_HCTM:
+	case NVME_FEAT_NOPSC:
+	case NVME_FEAT_RRL:
+	case NVME_FEAT_PLM_CONFIG:
+	case NVME_FEAT_PLM_WINDOW:
+	case NVME_FEAT_HOST_BEHAVIOR:
+	case NVME_FEAT_SANITIZE:
+	case NVME_FEAT_VENDOR_START ... NVME_FEAT_VENDOR_END:
+		return nvmet_setup_passthru_command(req);
+
+	case NVME_FEAT_ASYNC_EVENT:
+		/* There is no support for forwarding ASYNC events */
+	case NVME_FEAT_IRQ_COALESCE:
+	case NVME_FEAT_IRQ_CONFIG:
+		/* The IRQ settings will not apply to the target controller */
+	case NVME_FEAT_HOST_MEM_BUF:
+		/*
+		 * Any HMB that's set will not be passed through and will
+		 * not work as expected
+		 */
+	case NVME_FEAT_SW_PROGRESS:
+		/*
+		 * The Pre-Boot Software Load Count doesn't make much
+		 * sense for a target to export
+		 */
+	case NVME_FEAT_RESV_MASK:
+	case NVME_FEAT_RESV_PERSIST:
+		/* No reservations, see nvmet_parse_passthru_io_cmd() */
+	default:
+		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+	}
+}
+
+u16 nvmet_parse_passthru_admin_cmd(struct nvmet_req *req)
+{
+	/*
+	 * Passthru all vendor specific commands
+	 */
+	if (req->cmd->common.opcode >= nvme_admin_vendor_start)
+		return nvmet_setup_passthru_command(req);
+
+	switch (req->cmd->common.opcode) {
+	case nvme_admin_async_event:
+		req->execute = nvmet_execute_async_event;
+		return NVME_SC_SUCCESS;
+	case nvme_admin_keep_alive:
+		/*
+		 * Most PCIe ctrls don't support keep alive cmd, we route keep
+		 * alive to the non-passthru mode. In future please change this
+		 * code when PCIe ctrls with keep alive support available.
+		 */
+		req->execute = nvmet_execute_keep_alive;
+		return NVME_SC_SUCCESS;
+	case nvme_admin_set_features:
+		switch (le32_to_cpu(req->cmd->features.fid)) {
+		case NVME_FEAT_ASYNC_EVENT:
+		case NVME_FEAT_KATO:
+		case NVME_FEAT_NUM_QUEUES:
+		case NVME_FEAT_HOST_ID:
+			req->execute = nvmet_execute_set_features;
+			return NVME_SC_SUCCESS;
+		case NVME_FEAT_HOST_BEHAVIOR:
+			req->execute = nvmet_passthru_set_host_behaviour;
+			return NVME_SC_SUCCESS;
+		default:
+			return nvmet_passthru_get_set_features(req);
+		}
+		break;
+	case nvme_admin_get_features:
+		switch (le32_to_cpu(req->cmd->features.fid)) {
+		case NVME_FEAT_ASYNC_EVENT:
+		case NVME_FEAT_KATO:
+		case NVME_FEAT_NUM_QUEUES:
+		case NVME_FEAT_HOST_ID:
+			req->execute = nvmet_execute_get_features;
+			return NVME_SC_SUCCESS;
+		default:
+			return nvmet_passthru_get_set_features(req);
+		}
+		break;
+	case nvme_admin_identify:
+		switch (req->cmd->identify.cns) {
+		case NVME_ID_CNS_CTRL:
+			req->execute = nvmet_passthru_execute_cmd;
+			req->p.use_workqueue = true;
+			return NVME_SC_SUCCESS;
+		case NVME_ID_CNS_NS:
+			req->execute = nvmet_passthru_execute_cmd;
+			req->p.use_workqueue = true;
+			return NVME_SC_SUCCESS;
+		default:
+			return nvmet_setup_passthru_command(req);
+		}
+	case nvme_admin_get_log_page:
+		return nvmet_setup_passthru_command(req);
+	default:
+		/* Reject commands not in the allowlist above */
+		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+	}
+}