[v2 1/1] scsi: target: Add 8Fh VPD page

[Sergey Samoylenko <s.samoylenko@yadro.com>]

Third-party Copy VPD page announces capabilities supported
by the TCM copy manager.

Some systems use this page. The ESXi 7.0 requests
the page if it sees it in the supported VPD Pages list,
Windows detects ODX support using the 8Fh page [1].

1. https://www.slideshare.net/CalvinChen5/a-joint-effort-of-the-storage-industry

Reviewed-by: Konstantin Shelekhin <k.shelekhin@yadro.com>
Reviewed-by: Dmitry Bogdanov <d.bogdanov@yadro.com>
Reviewed-by: Anastasia Kovaleva <a.kovaleva@yadro.com>
Signed-off-by: Sergey Samoylenko <s.samoylenko@yadro.com>
---
 drivers/target/target_core_spc.c | 264 ++++++++++++++++++++++++++++++-
 1 file changed, 260 insertions(+), 4 deletions(-)

diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index 22703a0dbd07..a2c914cd9f9d 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -506,6 +506,251 @@ spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
 	return 0;
 }
 
+/* Third-party copy descriptor length is a multiple of four */
+static u16 __spc_evpd_8f_desc_calc_padding(u16 len)
+{
+	return (4 - (len & 3)) & 3;
+}
+
+/* Supported Commands third-party copy descriptor, spc4 7.8.17.4 */
+static int spc_evpd_8f_encode_supp_cmds(unsigned char *out, int out_len, int out_off)
+{
+	unsigned char buf[64] = {0};
+	u16 off = 0;
+
+	/*
+	 * TCM supports only two Third-party copy commands:
+	 *   83h/00h - EXTENDED COPY(LID1)
+	 *   84h/03h - RECEIVE COPY OPERATING PARAMETERS
+	 */
+
+	/* Set THIRD-PARTY COPY DESCRIPTOR TYPE (0001h) */
+	put_unaligned_be16(0x0001, &buf[off]);
+	off += 2;
+	/* Skip THIRD-PARTY COPY DESCRIPTOR LENGTH */
+	off += 2;
+	/* Set COMMANDS SUPPORTED LIST LENGTH for two codes */
+	buf[off++] = 6;
+	/* First command support descriptor (EXTENDED COPY(LID1)) */
+	buf[off++] = EXTENDED_COPY; /* operation code */
+	buf[off++] = 1; /* action list length */
+	buf[off++] = 0; /* service action */
+	/* Second descriptor (RECEIVE COPY OPERATING PARAMETERS) */
+	buf[off++] = RECEIVE_COPY_RESULTS;
+	buf[off++] = 1;
+	buf[off++] = RCR_SA_OPERATING_PARAMETERS;
+	/* Descriptor pad */
+	off += __spc_evpd_8f_desc_calc_padding(off);
+
+	BUG_ON(off > ARRAY_SIZE(buf));
+
+	/* Set THIRD-PARTY COPY DESCRIPTOR LENGTH */
+	put_unaligned_be16(off - 4, &buf[2]);
+
+	if (out_off + off <= out_len)
+		memcpy(&out[out_off], buf, off);
+
+	return off;
+}
+
+/* Parameter Data third-party copy descriptor, spc4 7.8.17.5 */
+static int spc_evpd_8f_encode_param_data(unsigned char *out, int out_len, int out_off)
+{
+	unsigned char buf[64] = {0};
+	u16 off = 0;
+
+	/* Set THIRD-PARTY COPY DESCRIPTOR TYPE (0004h) */
+	put_unaligned_be16(0x0004, &buf[off]);
+	off += 2;
+	/* Set THIRD-PARTY COPY DESCRIPTOR LENGTH (001Ch) */
+	put_unaligned_be16(0x001c, &buf[off]);
+	off += 2;
+	/* Skip over Reserved */
+	off += 4;
+	/* Set MAXIMUM CSCD DESCRIPTOR COUNT */
+	put_unaligned_be16(RCR_OP_MAX_TARGET_DESC_COUNT, &buf[off]);
+	off += 2;
+	/* Set MAXIMUM SEGMENT DESCRIPTOR COUNT */
+	put_unaligned_be16(RCR_OP_MAX_SG_DESC_COUNT, &buf[off]);
+	off += 2;
+	/* Set MAXIMUM DESCRIPTOR LIST LENGTH */
+	put_unaligned_be32(RCR_OP_MAX_DESC_LIST_LEN, &buf[off]);
+	off += 4;
+	/*
+	 * The MAXIMUM INLINE DATA LENGTH field should be set to ZERO
+	 * if the copy manager does not support segment descriptor
+	 * type code 04h.
+	 */
+	off += 4;
+	/* Skip over Reserved */
+	off += 12;
+
+	BUG_ON(off > ARRAY_SIZE(buf));
+
+	if (out_off + off <= out_len)
+		memcpy(&out[out_off], buf, off);
+
+	return off;
+}
+
+/* Supported Descriptors third-party copy descriptor, spc4 7.8.17.6 */
+static int spc_evpd_8f_encode_supp_descrs(unsigned char *out, int out_len, int out_off)
+{
+	unsigned char buf[64] = {0};
+	u16 off = 0;
+
+	/*
+	 * List of supported descriptor type codes:
+	 *   02h - Copy from block device to block device segment descriptor
+	 *   E4h - Identification Descriptor CSCD descriptor
+	 */
+
+	/* Set THIRD-PARTY COPY DESCRIPTOR TYPE (0008h) */
+	put_unaligned_be16(0x0008, &buf[off]);
+	off += 2;
+	/* Skip THIRD-PARTY COPY DESCRIPTOR LENGTH */
+	off += 2;
+	/* Set SUPPORTED DESCRIPTOR LIST LENGTH */
+	buf[off++] = 2;
+	/* List of supported descriptor type codes */
+	buf[off++] = 0x02;
+	buf[off++] = 0xe4;
+	/* Descriptor pad */
+	off += __spc_evpd_8f_desc_calc_padding(off);
+
+	BUG_ON(off > ARRAY_SIZE(buf));
+
+	/* Set THIRD-PARTY COPY DESCRIPTOR LENGTH */
+	put_unaligned_be16(off - 4, &buf[2]);
+
+	if (out_off + off <= out_len)
+		memcpy(&out[out_off], buf, off);
+
+	return off;
+}
+
+/* Supported CSCD Descriptor IDs third-party copy descriptor, spc4 7.8.17.7 */
+static int spc_evpd_8f_encode_supp_cscd_descr_id(unsigned char *out, int out_len, int out_off)
+{
+	unsigned char buf[64] = {0};
+	u16 off = 0;
+
+	/*
+	 * The TCM copy manager doesn't support CSCD Descriptod IDs other
+	 * than 0000h and therefore IDs List should be zero length.
+	 */
+
+	/* Set THIRD-PARTY COPY DESCRIPTOR TYPE (000Ch) */
+	put_unaligned_be16(0x000c, &buf[off]);
+	off += 2;
+	/* Skip THIRD-PARTY COPY DESCRIPTOR LENGTH */
+	off += 2;
+	/* Set SUPPORTED CSCD DESCRIPTOR IDS LIST LENGTH to ZERO */
+	off += 2;
+	/* Descriptor pad */
+	off += __spc_evpd_8f_desc_calc_padding(off);
+
+	BUG_ON(off > ARRAY_SIZE(buf));
+
+	/* Set THIRD-PARTY COPY DESCRIPTOR LENGTH */
+	put_unaligned_be16(off - 4, &buf[2]);
+
+	if (out_off + off <= out_len)
+		memcpy(&out[out_off], buf, off);
+
+	return off;
+}
+
+/* General Copy Operations third-party copy descriptor, spc4 7.8.17.10 */
+static int spc_evpd_8f_encode_general_copy_ops(unsigned char *out, int out_len, int out_off)
+{
+	unsigned char buf[64] = {0};
+	u16 off = 0;
+
+	/* Set THIRD-PARTY COPY DESCRIPTOR TYPE (8001h) */
+	put_unaligned_be16(0x8001, &buf[off]);
+	off += 2;
+	/* Set THIRD-PARTY COPY DESCRIPTOR LENGTH (0020h) */
+	put_unaligned_be16(0x0020, &buf[off]);
+	off += 2;
+	/* Set TOTAL CONCURRENT COPIES */
+	put_unaligned_be32(RCR_OP_TOTAL_CONCURR_COPIES, &buf[off]);
+	off += 4;
+	/* Set MAXIMUM IDENTIFIED CONCURRENT COPIES */
+	put_unaligned_be32(RCR_OP_MAX_CONCURR_COPIES, &buf[off]);
+	off += 4;
+	/* Set MAXIMUM SEGMENT LENGTH */
+	put_unaligned_be32(RCR_OP_MAX_SEGMENT_LEN, &buf[off]);
+	off += 4;
+	/* Set DATA SEGMENT GRANULARITY (log 2) */
+	buf[off++] = RCR_OP_DATA_SEG_GRAN_LOG2;
+	/*
+	 * Set INLINE DATA GRANULARITY (log 2) to ZERO.
+	 * TCM XCOPY manager does not support 04h (copy
+	 * inline data to stream device) descriptor type.
+	 */
+	off += 1;
+	/* Reserved */
+	off += 18;
+
+	BUG_ON(off > ARRAY_SIZE(buf));
+
+	if (out_off + off <= out_len)
+		memcpy(&out[out_off], buf, off);
+
+	return off;
+}
+
+/* Third-party Copy VPD page */
+static sense_reason_t
+spc_emulate_evpd_8f(struct se_cmd *cmd, unsigned char *buf)
+{
+	struct se_device *dev = cmd->se_dev;
+	int buf_len = SE_INQUIRY_BUF;
+	int off;
+	u16 page_len;
+
+	if (!dev->dev_attrib.emulate_3pc)
+		return TCM_INVALID_CDB_FIELD;
+
+	/*
+	 * Since the Third-party copy manager in TCM is quite simple
+	 * and supports only two commands, the function sets
+	 * many descriptor parameters as constants.
+	 *
+	 * As the Copy manager supports the EXTENDED COPY(LID1) command,
+	 * the Third-party Copy VPD page should include five mandatory
+	 * Third-party copy descriptors. Its are:
+	 *   0001h - Supported Commands
+	 *   0004h - Parameter Data
+	 *   0008h - Supported Descriptors
+	 *   000Ch - Supported CSCD Descriptor IDs
+	 *   8001h - General Copy Operations
+	 *
+	 * See spc4 section 7.8.17
+	 */
+
+	off = 4;
+
+	/* Fill descriptors */
+	off += spc_evpd_8f_encode_supp_cmds(&buf[0], buf_len, off);
+	off += spc_evpd_8f_encode_param_data(&buf[0], buf_len, off);
+	off += spc_evpd_8f_encode_supp_descrs(&buf[0], buf_len, off);
+	off += spc_evpd_8f_encode_supp_cscd_descr_id(&buf[0], buf_len, off);
+	off += spc_evpd_8f_encode_general_copy_ops(&buf[0], buf_len, off);
+
+	if (WARN_ON(off > buf_len))
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+	/*
+	 * Page Length for VPD 0x8f
+	 */
+	page_len = &buf[off] - &buf[0] - 4;
+	put_unaligned_be16(page_len, &buf[2]);
+
+	return 0;
+}
+
 /* Block Limits VPD page */
 static sense_reason_t
 spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf)
@@ -702,6 +947,7 @@ static struct {
 	{ .page = 0x80, .emulate = spc_emulate_evpd_80 },
 	{ .page = 0x83, .emulate = spc_emulate_evpd_83 },
 	{ .page = 0x86, .emulate = spc_emulate_evpd_86 },
+	{ .page = 0x8f, .emulate = spc_emulate_evpd_8f },
 	{ .page = 0xb0, .emulate = spc_emulate_evpd_b0 },
 	{ .page = 0xb1, .emulate = spc_emulate_evpd_b1 },
 	{ .page = 0xb2, .emulate = spc_emulate_evpd_b2 },
@@ -712,7 +958,9 @@ static struct {
 static sense_reason_t
 spc_emulate_evpd_00(struct se_cmd *cmd, unsigned char *buf)
 {
-	int p;
+	bool emulate_3pc = cmd->se_dev->dev_attrib.emulate_3pc;
+	int i, p;
+	uint8_t page;
 
 	/*
 	 * Only report the INQUIRY EVPD=1 pages after a valid NAA
@@ -720,9 +968,17 @@ spc_emulate_evpd_00(struct se_cmd *cmd, unsigned char *buf)
 	 * during device creation/restart.
 	 */
 	if (cmd->se_dev->dev_flags & DF_EMULATED_VPD_UNIT_SERIAL) {
-		buf[3] = ARRAY_SIZE(evpd_handlers);
-		for (p = 0; p < ARRAY_SIZE(evpd_handlers); ++p)
-			buf[p + 4] = evpd_handlers[p].page;
+		for (i = 0, p = 4; i < ARRAY_SIZE(evpd_handlers); ++i) {
+			page = evpd_handlers[i].page;
+			/*
+			 * The 8Fh VPD page is announced only if the copy
+			 * manager is activated.
+			 */
+			if ((page == 0x8f) && !emulate_3pc)
+				continue;
+			buf[p++] = page;
+		}
+		buf[3] = p - 4;
 	}
 
 	return 0;
-- 
2.25.1