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Subject[PATCH v10 7/9] nvmet-passthru: Add passthru code to process commands
Add passthru command handling capability for the NVMeOF target and
export passthru APIs which are used to integrate passthru
code with nvmet-core.

The new file passthru.c handles passthru cmd parsing and execution.
In the passthru mode, we create a block layer request from the nvmet
request and map the data on to the block layer request. Only admin
commands on a white list are let through which includes vendor specific
commands.

Based-on-a-patch-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
drivers/nvme/target/Makefile | 1 +
drivers/nvme/target/admin-cmd.c | 7 +-
drivers/nvme/target/core.c | 3 +
drivers/nvme/target/nvmet.h | 39 ++++
drivers/nvme/target/passthru.c | 348 ++++++++++++++++++++++++++++++++
include/linux/nvme.h | 1 +
6 files changed, 397 insertions(+), 2 deletions(-)
create mode 100644 drivers/nvme/target/passthru.c

diff --git a/drivers/nvme/target/Makefile b/drivers/nvme/target/Makefile
index 2b33836f3d3e..ebf91fc4c72e 100644
--- a/drivers/nvme/target/Makefile
+++ b/drivers/nvme/target/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_NVME_TARGET_TCP) += nvmet-tcp.o

nvmet-y += core.o configfs.o admin-cmd.o fabrics-cmd.o \
discovery.o io-cmd-file.o io-cmd-bdev.o
+nvmet-$(CONFIG_NVME_TARGET_PASSTHRU) += passthru.o
nvme-loop-y += loop.o
nvmet-rdma-y += rdma.o
nvmet-fc-y += fc.o
diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 56c21b501185..4f13e403e2f9 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -706,7 +706,7 @@ u16 nvmet_set_feat_async_event(struct nvmet_req *req, u32 mask)
return 0;
}

-static void nvmet_execute_set_features(struct nvmet_req *req)
+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);
@@ -772,7 +772,7 @@ void nvmet_get_feat_async_event(struct nvmet_req *req)
nvmet_set_result(req, READ_ONCE(req->sq->ctrl->aen_enabled));
}

-static void nvmet_execute_get_features(struct nvmet_req *req)
+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);
@@ -888,6 +888,9 @@ u16 nvmet_parse_admin_cmd(struct nvmet_req *req)
if (unlikely(ret))
return ret;

+ if (nvmet_req_passthru_ctrl(req))
+ return nvmet_parse_passthru_admin_cmd(req);
+
switch (cmd->common.opcode) {
case nvme_admin_get_log_page:
req->execute = nvmet_execute_get_log_page;
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 28438b833c1b..248818f378e3 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -831,6 +831,9 @@ static u16 nvmet_parse_io_cmd(struct nvmet_req *req)
if (unlikely(ret))
return ret;

+ if (nvmet_req_passthru_ctrl(req))
+ return nvmet_setup_passthru_command(req);
+
req->ns = nvmet_find_namespace(req->sq->ctrl, cmd->rw.nsid);
if (unlikely(!req->ns)) {
req->error_loc = offsetof(struct nvme_common_command, nsid);
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 46df45e837c9..37fc30d2a2c4 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -227,6 +227,10 @@ struct nvmet_subsys {

struct config_group namespaces_group;
struct config_group allowed_hosts_group;
+
+#ifdef CONFIG_NVME_TARGET_PASSTHRU
+ struct nvme_ctrl *passthru_ctrl;
+#endif /* CONFIG_NVME_TARGET_PASSTHRU */
};

static inline struct nvmet_subsys *to_subsys(struct config_item *item)
@@ -302,6 +306,11 @@ struct nvmet_req {
struct bio_vec *bvec;
struct work_struct work;
} f;
+ struct {
+ struct request *rq;
+ struct work_struct work;
+ u16 (*end_req)(struct nvmet_req *req);
+ } p;
};
int sg_cnt;
/* data length as parsed from the SGL descriptor: */
@@ -378,6 +387,8 @@ void nvmet_req_complete(struct nvmet_req *req, u16 status);
int nvmet_req_alloc_sgl(struct nvmet_req *req);
void nvmet_req_free_sgl(struct nvmet_req *req);

+void nvmet_execute_set_features(struct nvmet_req *req);
+void nvmet_execute_get_features(struct nvmet_req *req);
void nvmet_execute_keep_alive(struct nvmet_req *req);

void nvmet_cq_setup(struct nvmet_ctrl *ctrl, struct nvmet_cq *cq, u16 qid,
@@ -499,6 +510,34 @@ static inline u32 nvmet_dsm_len(struct nvmet_req *req)
sizeof(struct nvme_dsm_range);
}

+#ifdef CONFIG_NVME_TARGET_PASSTHRU
+u16 nvmet_parse_passthru_admin_cmd(struct nvmet_req *req);
+u16 nvmet_setup_passthru_command(struct nvmet_req *req);
+static inline struct nvme_ctrl *nvmet_passthru_ctrl(struct nvmet_subsys *subsys)
+{
+ return subsys->passthru_ctrl;
+}
+#else /* CONFIG_NVME_TARGET_PASSTHRU */
+static inline u16 nvmet_parse_passthru_admin_cmd(struct nvmet_req *req)
+{
+ return 0;
+}
+static inline u16 nvmet_setup_passthru_command(struct nvmet_req *req)
+{
+ return 0;
+}
+static inline struct nvme_ctrl *nvmet_passthru_ctrl(struct nvmet_subsys *subsys)
+{
+ return NULL;
+}
+#endif /* CONFIG_NVME_TARGET_PASSTHRU */
+
+static inline struct nvme_ctrl *
+nvmet_req_passthru_ctrl(struct nvmet_req *req)
+{
+ return nvmet_passthru_ctrl(req->sq->ctrl->subsys);
+}
+
u16 errno_to_nvme_status(struct nvmet_req *req, int errno);

/* Convert a 32-bit number to a 16-bit 0's based number */
diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
new file mode 100644
index 000000000000..01127bfa6c8a
--- /dev/null
+++ b/drivers/nvme/target/passthru.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe Over Fabrics Target Passthrough command implementation.
+ *
+ * Copyright (c) 2017-2018 Western Digital Corporation or its
+ * affiliates.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+
+#include "../host/nvme.h"
+#include "nvmet.h"
+
+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->p.end_req)
+ status = req->p.end_req(req);
+
+ 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;
+
+ for_each_sg(req->sg, sg, req->sg_cnt, i) {
+ if (bio_add_page(bio, sg_page(sg), sg->length,
+ sg->offset) != sg->length) {
+ ret = blk_rq_append_bio(rq, &bio);
+ if (unlikely(ret))
+ return ret;
+
+ bio->bi_opf = req_op(rq) | op_flags;
+ bio = bio_alloc(GFP_KERNEL,
+ min(sg_cnt, BIO_MAX_PAGES));
+ }
+ sg_cnt--;
+ }
+
+ ret = blk_rq_append_bio(rq, &bio);
+ if (unlikely(ret))
+ return ret;
+
+ return 0;
+}
+
+static void nvmet_passthru_execute_cmd(struct nvmet_req *req)
+{
+ struct nvme_ctrl *ctrl = nvmet_req_passthru_ctrl(req);
+ struct nvme_ns *ns = NULL;
+ struct request *rq = NULL;
+ struct request_queue *q;
+ 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;
+ }
+ }
+
+ if (ns)
+ q = ns->queue;
+ else
+ q = ctrl->admin_q;
+
+ 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 (blk_rq_nr_phys_segments(rq) > queue_max_segments(rq->q)) {
+ status = NVME_SC_INVALID_FIELD;
+ goto fail_out;
+ }
+
+ if ((blk_rq_payload_bytes(rq) >> 9) > queue_max_hw_sectors(rq->q)) {
+ status = NVME_SC_INVALID_FIELD;
+ 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.end_req || 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);
+}
+
+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 limitted 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->has_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;
+
+ 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;
+}
+
+u16 nvmet_setup_passthru_command(struct nvmet_req *req)
+{
+ req->p.end_req = NULL;
+ req->execute = nvmet_passthru_execute_cmd;
+ return NVME_SC_SUCCESS;
+}
+
+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:
+ req->execute = nvmet_execute_set_features;
+ return NVME_SC_SUCCESS;
+ default:
+ return nvmet_setup_passthru_command(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:
+ req->execute = nvmet_execute_get_features;
+ return NVME_SC_SUCCESS;
+ default:
+ return nvmet_setup_passthru_command(req);
+ }
+ break;
+ case nvme_admin_identify:
+ switch (req->cmd->identify.cns) {
+ case NVME_ID_CNS_CTRL:
+ req->execute = nvmet_passthru_execute_cmd;
+ req->p.end_req = nvmet_passthru_override_id_ctrl;
+ return NVME_SC_SUCCESS;
+ case NVME_ID_CNS_NS:
+ req->execute = nvmet_passthru_execute_cmd;
+ req->p.end_req = nvmet_passthru_override_id_ns;
+ return NVME_SC_SUCCESS;
+ default:
+ return nvmet_setup_passthru_command(req);
+ }
+ case nvme_admin_get_log_page:
+ return nvmet_setup_passthru_command(req);
+ default:
+ /* By default, blacklist all admin commands */
+ return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+ }
+}
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 3d5189f46cb1..e29f4b8145fa 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -858,6 +858,7 @@ enum nvme_admin_opcode {
nvme_admin_security_recv = 0x82,
nvme_admin_sanitize_nvm = 0x84,
nvme_admin_get_lba_status = 0x86,
+ nvme_admin_vendor_start = 0xC0,
};

#define nvme_admin_opcode_name(opcode) { opcode, #opcode }
--
2.20.1
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