scsi-disk: implement READ DISC INFORMATION

This command is not necessary for CD-ROM and DVD-ROM, but some versions of
udev trip on its absence.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi-defs.h

@@ -82,6 +82,7 @@
 #define GET_EVENT_STATUS_NOTIFICATION 0x4a
 #define LOG_SELECT            0x4c
 #define LOG_SENSE             0x4d
+#define READ_DISC_INFORMATION 0x51
 #define RESERVE_TRACK         0x53
 #define MODE_SELECT_10        0x55
 #define RESERVE_10            0x56

hw/scsi-disk.c

@@ -724,6 +724,39 @@ static inline bool media_is_cd(SCSIDiskState *s)
     return nb_sectors <= CD_MAX_SECTORS;
 }
 
+static int scsi_read_disc_information(SCSIDiskState *s, SCSIDiskReq *r,
+                                      uint8_t *outbuf)
+{
+    uint8_t type = r->req.cmd.buf[1] & 7;
+
+    if (s->qdev.type != TYPE_ROM) {
+        return -1;
+    }
+
+    /* Types 1/2 are only defined for Blu-Ray.  */
+    if (type != 0) {
+        scsi_check_condition(r, SENSE_CODE(INVALID_FIELD));
+        return -1;
+    }
+
+    memset(outbuf, 0, 34);
+    outbuf[1] = 32;
+    outbuf[2] = 0xe; /* last session complete, disc finalized */
+    outbuf[3] = 1;   /* first track on disc */
+    outbuf[4] = 1;   /* # of sessions */
+    outbuf[5] = 1;   /* first track of last session */
+    outbuf[6] = 1;   /* last track of last session */
+    outbuf[7] = 0x20; /* unrestricted use */
+    outbuf[8] = 0x00; /* CD-ROM or DVD-ROM */
+    /* 9-10-11: most significant byte corresponding bytes 4-5-6 */
+    /* 12-23: not meaningful for CD-ROM or DVD-ROM */
+    /* 24-31: disc bar code */
+    /* 32: disc application code */
+    /* 33: number of OPC tables */
+
+    return 34;
+}
+
 static int scsi_read_dvd_structure(SCSIDiskState *s, SCSIDiskReq *r,
                                    uint8_t *outbuf)
 {
@@ -1363,6 +1396,12 @@ static int scsi_disk_emulate_command(SCSIDiskReq *r)
             goto illegal_request;
         }
         break;
+    case READ_DISC_INFORMATION:
+        buflen = scsi_read_disc_information(s, r, outbuf);
+        if (buflen < 0) {
+            goto illegal_request;
+        }
+        break;
     case READ_DVD_STRUCTURE:
         buflen = scsi_read_dvd_structure(s, r, outbuf);
         if (buflen < 0) {
@@ -1490,6 +1529,7 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t *buf)
     case ALLOW_MEDIUM_REMOVAL:
     case READ_CAPACITY_10:
     case READ_TOC:
+    case READ_DISC_INFORMATION:
     case READ_DVD_STRUCTURE:
     case GET_CONFIGURATION:
     case GET_EVENT_STATUS_NOTIFICATION: