path: root/drivers/nvme/target/passthru.c

// 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);

/*
 * xarray to maintain one passthru subsystem per nvme controller.
 */
static DEFINE_XARRAY(passthru_subsystems);

void nvmet_passthrough_override_cap(struct nvmet_ctrl *ctrl)
{
	/*
	 * Multiple command set support can only be declared if the underlying
	 * controller actually supports it.
	 */
	if (!nvme_multi_css(ctrl->subsys->passthru_ctrl))
		ctrl->cap &= ~(1ULL << 43);
}

static u16 nvmet_passthru_override_id_descs(struct nvmet_req *req)
{
	struct nvmet_ctrl *ctrl = req->sq->ctrl;
	u16 status = NVME_SC_SUCCESS;
	int pos, len;
	bool csi_seen = false;
	void *data;
	u8 csi;

	if (!ctrl->subsys->clear_ids)
		return status;

	data = kzalloc(NVME_IDENTIFY_DATA_SIZE, GFP_KERNEL);
	if (!data)
		return NVME_SC_INTERNAL;

	status = nvmet_copy_from_sgl(req, 0, data, NVME_IDENTIFY_DATA_SIZE);
	if (status)
		goto out_free;

	for (pos = 0; pos < NVME_IDENTIFY_DATA_SIZE; pos += len) {
		struct nvme_ns_id_desc *cur = data + pos;

		if (cur->nidl == 0)
			break;
		if (cur->nidt == NVME_NIDT_CSI) {
			memcpy(&csi, cur + 1, NVME_NIDT_CSI_LEN);
			csi_seen = true;
			break;
		}
		len = sizeof(struct nvme_ns_id_desc) + cur->nidl;
	}

	memset(data, 0, NVME_IDENTIFY_DATA_SIZE);
	if (csi_seen) {
		struct nvme_ns_id_desc *cur = data;

		cur->nidt = NVME_NIDT_CSI;
		cur->nidl = NVME_NIDT_CSI_LEN;
		memcpy(cur + 1, &csi, NVME_NIDT_CSI_LEN);
	}
	status = nvmet_copy_to_sgl(req, 0, data, NVME_IDENTIFY_DATA_SIZE);
out_free:
	kfree(data);
	return status;
}

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;
	unsigned int 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_SECTORS_SHIFT,
				      pctrl->max_hw_sectors);

	/*
	 * nvmet_passthru_map_sg is limitted to using a single bio so limit
	 * the mdts based on BIO_MAX_VECS as well
	 */
	max_hw_sectors = min_not_zero(BIO_MAX_VECS << PAGE_SECTORS_SHIFT,
				      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(ctrl));

	/* 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 passthru 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;

	if (req->sq->ctrl->subsys->clear_ids) {
		memset(id->nguid, 0, NVME_NIDT_NGUID_LEN);
		memset(id->eui64, 0, NVME_NIDT_EUI64_LEN);
	}

	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;
	struct nvme_ctrl *ctrl = nvme_req(rq)->ctrl;
	struct nvme_ns *ns = rq->q->queuedata;
	u32 effects;
	int status;

	effects = nvme_passthru_start(ctrl, ns, req->cmd->common.opcode);
	status = nvme_execute_rq(rq, false);
	if (status == NVME_SC_SUCCESS &&
	    req->cmd->common.opcode == nvme_admin_identify) {
		switch (req->cmd->identify.cns) {
		case NVME_ID_CNS_CTRL:
			status = nvmet_passthru_override_id_ctrl(req);
			break;
		case NVME_ID_CNS_NS:
			status = nvmet_passthru_override_id_ns(req);
			break;
		case NVME_ID_CNS_NS_DESC_LIST:
			status = nvmet_passthru_override_id_descs(req);
			break;
		}
	} else if (status < 0)
		status = NVME_SC_INTERNAL;

	req->cqe->result = nvme_req(rq)->result;
	nvmet_req_complete(req, status);
	blk_mq_free_request(rq);

	if (effects)
		nvme_passthru_end(ctrl, ns, effects, req->cmd, status);
}

static enum rq_end_io_ret 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_mq_free_request(rq);
	return RQ_END_IO_NONE;
}

static int nvmet_passthru_map_sg