From 456d0bab4f280e3fe4b8041a89385547b02454e0 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Tue, 9 May 2017 11:24:35 +0200

Subject: [PATCH 2/4] blockcmd: generic SCSI luns enumeration

RH-Author: Paolo Bonzini <pbonzini@redhat.com>

Message-id: <20170509112437.30666-3-pbonzini@redhat.com>

Patchwork-id: 75051

O-Subject: [RHEL7.4 seabios PATCH 2/4] blockcmd: generic SCSI luns enumeration

Bugzilla: 1020622

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

RH-Acked-by: Fam Zheng <famz@redhat.com>

From: Roman Kagan <rkagan@virtuozzo.com>

Add two generic functions to discover active LUNs on a SCSI target.

The functions take a temporary drive descriptor on the target, and a

callback to create a new drive descriptor with a new LUN using the

temporary one as a template.

One of the functions performs REPORT LUNS on the temporary drive to

obtain the list of candidate luns; the other sequentially iterates the

lun numbers up to the given maximum, and is meant as a fallback.  Both

functions return the number of successfully created drive descriptors,

or a negative number if an error occured.

This will allow to lift the limitation of most of the SCSI drivers that

support booting off the LUN #0 only.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

(cherry picked from commit 750188dfb35f61f1533f1138d6972b19f36f1a2c)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 src/hw/blockcmd.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++++

 src/hw/blockcmd.h |  4 +++

 2 files changed, 98 insertions(+)

diff --git a/src/hw/blockcmd.c b/src/hw/blockcmd.c

index 5ad128e..324188d 100644

--- a/src/hw/blockcmd.c

+++ b/src/hw/blockcmd.c

@@ -13,6 +13,7 @@

 #include "std/disk.h" // DISK_RET_EPARAM

 #include "string.h" // memset

 #include "util.h" // timer_calc

+#include "malloc.h"

 /****************************************************************

@@ -181,6 +182,99 @@ scsi_is_ready(struct disk_op_s *op)

     return 0;

 }

+#define CDB_CMD_REPORT_LUNS  0xA0

+

+struct cdb_report_luns {

+    u8 command;

+    u8 reserved_01[5];

+    u32 length;

+    u8 pad[6];

+} PACKED;

+

+struct scsi_lun {

+    u16 lun[4];

+};

+

+struct cdbres_report_luns {

+    u32 length;

+    u32 reserved;

+    struct scsi_lun luns[];

+};

+

+static u64 scsilun2u64(struct scsi_lun *scsi_lun)

+{

+    int i;

+    u64 ret = 0;

+    for (i = 0; i < ARRAY_SIZE(scsi_lun->lun); i++)

+        ret |= be16_to_cpu(scsi_lun->lun[i]) << (16 * i);

+    return ret;

+}

+

+// Issue REPORT LUNS on a temporary drive and iterate reported luns calling

+// @add_lun for each

+int scsi_rep_luns_scan(struct drive_s *tmp_drive, scsi_add_lun add_lun)

+{

+    int ret = -1;

+    u32 maxluns = 511;

+    u32 nluns, i;

+    struct cdb_report_luns cdb = {

+        .command = CDB_CMD_REPORT_LUNS,

+    };

+    struct disk_op_s op = {

+        .drive_gf = tmp_drive,

+        .command = CMD_SCSI,

+        .count = 1,

+        .cdbcmd = &cdb,

+    };

+    struct cdbres_report_luns *resp;

+

+    ASSERT32FLAT();

+

+    while (1) {

+        op.blocksize = sizeof(struct cdbres_report_luns) +

+            maxluns * sizeof(struct scsi_lun);

+        op.buf_fl = malloc_tmp(op.blocksize);

+        if (!op.buf_fl) {

+            warn_noalloc();

+            return -1;

+        }

+

+        cdb.length = cpu_to_be32(op.blocksize);

+        if (process_op(&op) != DISK_RET_SUCCESS)

+            goto out;

+

+        resp = op.buf_fl;

+        nluns = be32_to_cpu(resp->length) / sizeof(struct scsi_lun);

+        if (nluns <= maxluns)

+            break;

+

+        free(op.buf_fl);

+        maxluns = nluns;

+    }

+

+    for (i = 0, ret = 0; i < nluns; i++) {

+        u64 lun = scsilun2u64(&resp->luns[i]);

+        if (lun >> 32)

+            continue;

+        ret += !add_lun((u32)lun, tmp_drive);

+    }

+out:

+    free(op.buf_fl);

+    return ret;

+}

+

+// Iterate LUNs on the target and call @add_lun for each

+int scsi_sequential_scan(struct drive_s *tmp_drive, u32 maxluns,

+                         scsi_add_lun add_lun)

+{

+    int ret;

+    u32 lun;

+

+    for (lun = 0, ret = 0; lun < maxluns; lun++)

+        ret += !add_lun(lun, tmp_drive);

+    return ret;

+}

+

 // Validate drive, find block size / sector count, and register drive.

 int

 scsi_drive_setup(struct drive_s *drive, const char *s, int prio)

diff --git a/src/hw/blockcmd.h b/src/hw/blockcmd.h

index b543f85..f18543e 100644

--- a/src/hw/blockcmd.h

+++ b/src/hw/blockcmd.h

@@ -106,5 +106,9 @@ int scsi_is_read(struct disk_op_s *op);

 int scsi_is_ready(struct disk_op_s *op);

 struct drive_s;

 int scsi_drive_setup(struct drive_s *drive, const char *s, int prio);

+typedef int (*scsi_add_lun)(u32 lun, struct drive_s *tmpl_drv);

+int scsi_rep_luns_scan(struct drive_s *tmp_drive, scsi_add_lun add_lun);

+int scsi_sequential_scan(struct drive_s *tmp_drive, u32 maxluns,

+                         scsi_add_lun add_lun);

 #endif // blockcmd.h

-- 

1.8.3.1