[RFC 2/4] SCSI media error reporting

[Tony Asleson <tasleson@redhat.com>]

Add abilility to return media errors for SCSI block devices.  Needs
improvement.

Signed-off-by: Tony Asleson <tasleson@redhat.com>
---
 hw/scsi/scsi-disk.c  | 33 +++++++++++++++++++++++++++++++++
 include/scsi/utils.h |  4 ++++
 scsi/utils.c         | 31 +++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+)

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 915641a0f1..a7f3274cdf 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -37,6 +37,7 @@
 #include "sysemu/dma.h"
 #include "qemu/cutils.h"
 #include "trace.h"
+#include "block/error_inject.h"
 
 #ifdef __linux
 #include <scsi/sg.h>
@@ -132,6 +133,18 @@ static void scsi_check_condition(SCSIDiskReq *r, SCSISense sense)
     scsi_req_complete(&r->req, CHECK_CONDITION);
 }
 
+/* Helper function for SCSI media error  */
+static void scsi_media_error(SCSIDiskReq *r, SCSISense sense, uint32_t lba)
+{
+    trace_scsi_disk_check_condition(r->req.tag, sense.key, sense.asc,
+                                    sense.ascq);
+
+    r->req.sense_len = scsi_build_sense_buf_info(r->req.sense,
+                                                  SCSI_SENSE_LEN, sense, lba,
+                                                  0x80, 32);
+    scsi_req_complete(&r->req, CHECK_CONDITION);
+}
+
 static void scsi_init_iovec(SCSIDiskReq *r, size_t size)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
@@ -2170,6 +2183,26 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf)
         }
         r->sector = r->req.cmd.lba * (s->qdev.blocksize / 512);
         r->sector_count = len * (s->qdev.blocksize / 512);
+
+        /*
+         * TODO Move this check to a more appropriate spot.  Additionally we
+         * also need to transfer the data that was read up before encountering
+         * the media error.
+         */
+        uint64_t error_sector = 0;
+        char device_id[32];
+        sprintf(device_id, "%lu", s->qdev.wwn);
+        if (error_in_read(device_id, r->sector, r->sector_count,
+                          &error_sector)) {
+            /*
+             * TODO Fix error reporting for disks > 2TiB
+             */
+            if (error_sector > 0xFFFFFFFF) {
+                error_sector = 0xFFFFFFFF;
+            }
+            scsi_media_error(r, SENSE_CODE(READ_ERROR), (uint32_t)error_sector);
+            return 0;
+        }
         break;
     case WRITE_6:
     case WRITE_10:
diff --git a/include/scsi/utils.h b/include/scsi/utils.h
index fbc5588279..02ae74287f 100644
--- a/include/scsi/utils.h
+++ b/include/scsi/utils.h
@@ -35,6 +35,10 @@ SCSISense scsi_parse_sense_buf(const uint8_t *in_buf, int in_len);
 int scsi_build_sense_buf(uint8_t *buf, size_t max_size, SCSISense sense,
                          bool fixed_sense);
 
+int scsi_build_sense_buf_info(uint8_t *out_buf, size_t size, SCSISense sense,
+                              uint32_t information, uint8_t sksv,
+                              uint16_t sense_key_specific_info);
+
 /*
  * Predefined sense codes
  */
diff --git a/scsi/utils.c b/scsi/utils.c
index c50e81fdb8..9c9f1735d0 100644
--- a/scsi/utils.c
+++ b/scsi/utils.c
@@ -147,6 +147,37 @@ int scsi_build_sense_buf(uint8_t *out_buf, size_t size, SCSISense sense,
     return len;
 }
 
+int scsi_build_sense_buf_info(uint8_t *out_buf, size_t size, SCSISense sense,
+                                uint32_t information, uint8_t sksv,
+                                uint16_t sense_key_specific_info)
+{
+    uint8_t buf[SCSI_SENSE_LEN] = { 0 };
+
+    buf[0] = 0xF0;  /* Valid bit set. */
+    buf[2] = sense.key;
+
+    /*
+     * Set bytes 3, 4, 5, 6 value of information field
+     */
+    *((uint32_t *)(&buf[3])) = cpu_to_be32(information);
+
+    buf[7] = 10;
+    buf[12] = sense.asc;
+    buf[13] = sense.ascq;
+
+    if (sksv) {
+        buf[15] = sksv;
+        /*
+         * Set bytes 16, 17 to Sense-key specific bytes
+         */
+        *((uint16_t *)&buf[16]) = cpu_to_be16(sense_key_specific_info);
+    }
+
+    int len = MIN(SCSI_SENSE_LEN, size);
+    memcpy(out_buf, buf, len);
+    return len;
+}
+
 int scsi_build_sense(uint8_t *buf, SCSISense sense)
 {
     return scsi_build_sense_buf(buf, SCSI_SENSE_LEN, sense, true);
-- 
2.21.0