nvmft: Add NVMeoF controller routines shared between kernel and userland

This includes functions to validate NVMe Qualified Names, compute an
initial value of the CAP property, validate changes to the CC
property, and populate the Identify Controller data structure for an
I/O controller.

Reviewed by:	imp
Sponsored by:	Chelsio Communications
Differential Revision:	https://reviews.freebsd.org/D44709

2 files changed, 306 insertions, 0 deletions

diff --git a/sys/dev/nvmf/controller/nvmft_subr.c b/sys/dev/nvmf/controller/nvmft_subr.c
new file mode 100644
index 000000000000..bb2bc0988e81
--- /dev/null
+++ b/sys/dev/nvmf/controller/nvmft_subr.c
@@ -0,0 +1,259 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023-2024 Chelsio Communications, Inc.
+ * Written by: John Baldwin <jhb@FreeBSD.org>
+ */
+
+#include <sys/types.h>
+#ifdef _KERNEL
+#include <sys/libkern.h>
+#else
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#endif
+
+#include <dev/nvmf/nvmf_proto.h>
+
+#include "nvmft_subr.h"
+
+bool
+nvmf_nqn_valid(const char *nqn)
+{
+	size_t len;
+
+	len = strnlen(nqn, NVME_NQN_FIELD_SIZE);
+	if (len == 0 || len > NVMF_NQN_MAX_LEN)
+		return (false);
+
+#ifdef STRICT_CHECKS
+	/*
+	 * Stricter checks from the spec.  Linux does not seem to
+	 * require these.
+	 */
+
+	/*
+	 * NVMF_NQN_MIN_LEN does not include '.', and require at least
+	 * one character of a domain name.
+	 */
+	if (len < NVMF_NQN_MIN_LEN + 2)
+		return (false);
+	if (memcmp("nqn.", nqn, strlen("nqn.")) != 0)
+		return (false);
+	nqn += strlen("nqn.");
+
+	/* Next 4 digits must be a year. */
+	for (u_int i = 0; i < 4; i++) {
+		if (!isdigit(nqn[i]))
+			return (false);
+	}
+	nqn += 4;
+
+	/* '-' between year and month. */
+	if (nqn[0] != '-')
+		return (false);
+	nqn++;
+
+	/* 2 digit month. */
+	for (u_int i = 0; i < 2; i++) {
+		if (!isdigit(nqn[i]))
+			return (false);
+	}
+	nqn += 2;
+
+	/* '.' between month and reverse domain name. */
+	if (nqn[0] != '.')
+		return (false);
+#endif
+	return (true);
+}
+
+uint64_t
+_nvmf_controller_cap(uint32_t max_io_qsize, uint8_t enable_timeout)
+{
+	uint32_t caphi, caplo;
+	u_int mps;
+
+	caphi = NVMEF(NVME_CAP_HI_REG_CMBS, 0) |
+	    NVMEF(NVME_CAP_HI_REG_PMRS, 0);
+	if (max_io_qsize != 0) {
+		mps = ffs(PAGE_SIZE) - 1;
+		if (mps < NVME_MPS_SHIFT)
+			mps = 0;
+		else
+			mps -= NVME_MPS_SHIFT;
+		caphi |= NVMEF(NVME_CAP_HI_REG_MPSMAX, mps) |
+		    NVMEF(NVME_CAP_HI_REG_MPSMIN, mps);
+	}
+	caphi |= NVMEF(NVME_CAP_HI_REG_BPS, 0) |
+	    NVMEF(NVME_CAP_HI_REG_CSS, NVME_CAP_HI_REG_CSS_NVM_MASK) |
+	    NVMEF(NVME_CAP_HI_REG_NSSRS, 0) |
+	    NVMEF(NVME_CAP_HI_REG_DSTRD, 0);
+
+	caplo = NVMEF(NVME_CAP_LO_REG_TO, enable_timeout) |
+	    NVMEF(NVME_CAP_LO_REG_AMS, 0) |
+	    NVMEF(NVME_CAP_LO_REG_CQR, 1);
+
+	if (max_io_qsize != 0)
+		caplo |= NVMEF(NVME_CAP_LO_REG_MQES, max_io_qsize - 1);
+
+	return ((uint64_t)caphi << 32 | caplo);
+}
+
+bool
+_nvmf_validate_cc(uint32_t max_io_qsize __unused, uint64_t cap, uint32_t old_cc,
+    uint32_t new_cc)
+{
+	uint32_t caphi, changes, field;
+
+	changes = old_cc ^ new_cc;
+	field = NVMEV(NVME_CC_REG_IOCQES, new_cc);
+	if (field != 0) {
+		/*
+		 * XXX: Linux's initiator writes a non-zero value to
+		 * IOCQES when connecting to a discovery controller.
+		 */
+#ifdef STRICT_CHECKS
+		if (max_io_qsize == 0)
+			return (false);
+#endif
+		if (field != 4)
+			return (false);
+	}
+	field = NVMEV(NVME_CC_REG_IOSQES, new_cc);
+	if (field != 0) {
+		/*
+		 * XXX: Linux's initiator writes a non-zero value to
+		 * IOCQES when connecting to a discovery controller.
+		 */
+#ifdef STRICT_CHECKS
+		if (max_io_qsize == 0)
+			return (false);
+#endif
+		if (field != 6)
+			return (false);
+	}
+	field = NVMEV(NVME_CC_REG_SHN, new_cc);
+	if (field == 3)
+		return (false);
+
+	field = NVMEV(NVME_CC_REG_AMS, new_cc);
+	if (field != 0)
+		return (false);
+
+	caphi = cap >> 32;
+	field = NVMEV(NVME_CC_REG_MPS, new_cc);
+	if (field < NVMEV(NVME_CAP_HI_REG_MPSMAX, caphi) ||
+	    field > NVMEV(NVME_CAP_HI_REG_MPSMIN, caphi))
+		return (false);
+
+	field = NVMEV(NVME_CC_REG_CSS, new_cc);
+	if (field != 0 && field != 0x7)
+		return (false);
+
+	/* AMS, MPS, and CSS can only be changed while CC.EN is 0. */
+	if (NVMEV(NVME_CC_REG_EN, old_cc) != 0 &&
+	    (NVMEV(NVME_CC_REG_AMS, changes) != 0 ||
+	    NVMEV(NVME_CC_REG_MPS, changes) != 0 ||
+	    NVMEV(NVME_CC_REG_CSS, changes) != 0))
+		return (false);
+
+	return (true);
+}
+
+void
+nvmf_controller_serial(char *buf, size_t len, u_long hostid)
+{
+	snprintf(buf, len, "HI:%lu", hostid);
+}
+
+void
+nvmf_strpad(char *dst, const char *src, size_t len)
+{
+	while (len > 0 && *src != '\0') {
+		*dst++ = *src++;
+		len--;
+	}
+	memset(dst, ' ', len);
+}
+
+void
+_nvmf_init_io_controller_data(uint16_t cntlid, uint32_t max_io_qsize,
+    const char *serial, const char *model, const char *firmware_version,
+    const char *subnqn, int nn, uint32_t ioccsz, uint32_t iorcsz,
+    struct nvme_controller_data *cdata)
+{
+	char *cp;
+
+	nvmf_strpad(cdata->sn, serial, sizeof(cdata->sn));
+	nvmf_strpad(cdata->mn, model, sizeof(cdata->mn));
+	nvmf_strpad(cdata->fr, firmware_version, sizeof(cdata->fr));
+	cp = memchr(cdata->fr, '-', sizeof(cdata->fr));
+	if (cp != NULL)
+		memset(cp, ' ', sizeof(cdata->fr) - (cp - (char *)cdata->fr));
+
+	/* FreeBSD OUI */
+	cdata->ieee[0] = 0xfc;
+	cdata->ieee[1] = 0x9c;
+	cdata->ieee[2] = 0x58;
+
+	cdata->ctrlr_id = htole16(cntlid);
+	cdata->ver = htole32(NVME_REV(1, 4));
+	cdata->ctratt = htole32(
+	    NVMEF(NVME_CTRLR_DATA_CTRATT_128BIT_HOSTID, 1) |
+	    NVMEF(NVME_CTRLR_DATA_CTRATT_TBKAS, 1));
+	cdata->cntrltype = 1;
+	cdata->acl = 3;
+	cdata->aerl = 3;
+
+	/* 1 read-only firmware slot */
+	cdata->frmw = NVMEF(NVME_CTRLR_DATA_FRMW_SLOT1_RO, 1) |
+	    NVMEF(NVME_CTRLR_DATA_FRMW_NUM_SLOTS, 1);
+
+	cdata->lpa = NVMEF(NVME_CTRLR_DATA_LPA_EXT_DATA, 1);
+
+	/* Single power state */
+	cdata->npss = 0;
+
+	/*
+	 * 1.2+ require a non-zero value for these even though it makes
+	 * no sense for Fabrics.
+	 */
+	cdata->wctemp = htole16(0x0157);
+	cdata->cctemp = cdata->wctemp;
+
+	/* 1 second granularity for KeepAlive */
+	cdata->kas = htole16(10);
+
+	cdata->sqes = NVMEF(NVME_CTRLR_DATA_SQES_MAX, 6) |
+	    NVMEF(NVME_CTRLR_DATA_SQES_MIN, 6);
+	cdata->cqes = NVMEF(NVME_CTRLR_DATA_CQES_MAX, 4) |
+	    NVMEF(NVME_CTRLR_DATA_CQES_MIN, 4);
+
+	cdata->maxcmd = htole16(max_io_qsize);
+	cdata->nn = htole32(nn);
+
+	cdata->vwc =
+	    NVMEF(NVME_CTRLR_DATA_VWC_ALL, NVME_CTRLR_DATA_VWC_ALL_NO) |
+	    NVMEM(NVME_CTRLR_DATA_VWC_PRESENT);
+
+	/* Transport-specific? */
+	cdata->sgls = htole32(
+	    NVMEF(NVME_CTRLR_DATA_SGLS_TRANSPORT_DATA_BLOCK, 1) |
+	    NVMEF(NVME_CTRLR_DATA_SGLS_ADDRESS_AS_OFFSET, 1) |
+	    NVMEF(NVME_CTRLR_DATA_SGLS_NVM_COMMAND_SET, 1));
+
+	strlcpy(cdata->subnqn, subnqn, sizeof(cdata->subnqn));
+
+	cdata->ioccsz = htole32(ioccsz / 16);
+	cdata->iorcsz = htole32(iorcsz / 16);
+
+	/* Transport-specific? */
+	cdata->icdoff = 0;
+
+	cdata->fcatt = 0;
+
+	/* Transport-specific? */
+	cdata->msdbd = 1;
+}
diff --git a/sys/dev/nvmf/controller/nvmft_subr.h b/sys/dev/nvmf/controller/nvmft_subr.h
new file mode 100644
index 000000000000..fbafa6047500
--- /dev/null
+++ b/sys/dev/nvmf/controller/nvmft_subr.h
@@ -0,0 +1,47 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023-2024 Chelsio Communications, Inc.
+ * Written by: John Baldwin <jhb@FreeBSD.org>
+ */
+
+#ifndef __NVMFT_SUBR_H__
+#define	__NVMFT_SUBR_H__
+
+/*
+ * Lower-level controller-specific routines shared between the kernel
+ * and userland.
+ */
+
+/* Validate a NVMe Qualified Name. */
+bool	nvmf_nqn_valid(const char *nqn);
+
+/* Compute the initial state of CAP for a controller. */
+uint64_t _nvmf_controller_cap(uint32_t max_io_qsize, uint8_t enable_timeout);
+
+/*
+ * Validate if a new value for CC is legal given the existing values of
+ * CAP and CC.
+ */
+bool	_nvmf_validate_cc(uint32_t max_io_qsize, uint64_t cap, uint32_t old_cc,
+    uint32_t new_cc);
+
+/* Generate a serial number string from a host ID. */
+void	nvmf_controller_serial(char *buf, size_t len, u_long hostid);
+
+/*
+ * Copy an ASCII string into the destination buffer but pad the end of
+ * the buffer with spaces and no terminating nul.
+ */
+void	nvmf_strpad(char *dst, const char *src, size_t len);
+
+/*
+ * Populate an Identify Controller data structure for an I/O
+ * controller.
+ */
+void	_nvmf_init_io_controller_data(uint16_t cntlid, uint32_t max_io_qsize,
+    const char *serial, const char *model, const char *firmware_version,
+    const char *subnqn, int nn, uint32_t ioccsz, uint32_t iorcsz,
+    struct nvme_controller_data *cdata);
+
+#endif	/* !__NVMFT_SUBR_H__ */