atapi: kill MODE SENSE(6), fix MODE SENSE(10)

Mode page 2A of emulated ATAPI DVD-ROM should have page length 0x14
like SCSI CD-ROM, rather than 0x12.

Mode page length is off by 8, as it should contain the length of the
payload after the first two bytes.

MODE SENSE(6) should be thrown out of ATAPI DVD-ROM emulation.  It is
not specified in the ATAPI list of MMC-2, and MMC-5 prescribes to use
MODE SENSE(10).  Anyway, its implementation is wrong.
Reported-by: NThomas Schmitt <scdbackup@gmx.net>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

hw/ide/atapi.c

@@ -695,12 +695,7 @@ static void cmd_mode_sense(IDEState *s, uint8_t *buf)
     int action, code;
     int max_len;
 
-    if (buf[0] == GPCMD_MODE_SENSE_10) {
-        max_len = ube16_to_cpu(buf + 7);
-    } else {
-        max_len = buf[4];
-    }
-
+    max_len = ube16_to_cpu(buf + 7);
     action = buf[2] >> 6;
     code = buf[2] & 0x3f;
 
@@ -708,7 +703,7 @@ static void cmd_mode_sense(IDEState *s, uint8_t *buf)
     case 0: /* current values */
         switch(code) {
         case MODE_PAGE_R_W_ERROR: /* error recovery */
-            cpu_to_ube16(&buf[0], 16 + 6);
+            cpu_to_ube16(&buf[0], 16 - 2);
             buf[2] = 0x70;
             buf[3] = 0;
             buf[4] = 0;
@@ -727,7 +722,7 @@ static void cmd_mode_sense(IDEState *s, uint8_t *buf)
             ide_atapi_cmd_reply(s, 16, max_len);
             break;
         case MODE_PAGE_AUDIO_CTL:
-            cpu_to_ube16(&buf[0], 24 + 6);
+            cpu_to_ube16(&buf[0], 24 - 2);
             buf[2] = 0x70;
             buf[3] = 0;
             buf[4] = 0;
@@ -746,7 +741,7 @@ static void cmd_mode_sense(IDEState *s, uint8_t *buf)
             ide_atapi_cmd_reply(s, 24, max_len);
             break;
         case MODE_PAGE_CAPABILITIES:
-            cpu_to_ube16(&buf[0], 28 + 6);
+            cpu_to_ube16(&buf[0], 30 - 2);
             buf[2] = 0x70;
             buf[3] = 0;
             buf[4] = 0;
@@ -755,7 +750,7 @@ static void cmd_mode_sense(IDEState *s, uint8_t *buf)
             buf[7] = 0;
 
             buf[8] = MODE_PAGE_CAPABILITIES;
-            buf[9] = 28 - 10;
+            buf[9] = 30 - 10;
             buf[10] = 0x3b; /* read CDR/CDRW/DVDROM/DVDR/DVDRAM */
             buf[11] = 0x00;
 
@@ -777,7 +772,9 @@ static void cmd_mode_sense(IDEState *s, uint8_t *buf)
             buf[25] = 0;
             buf[26] = 0;
             buf[27] = 0;
-            ide_atapi_cmd_reply(s, 28, max_len);
+            buf[28] = 0;
+            buf[29] = 0;
+            ide_atapi_cmd_reply(s, 30, max_len);
             break;
         default:
             goto error_cmd;
@@ -1043,7 +1040,6 @@ static const struct {
     [ 0x00 ] = { cmd_test_unit_ready,               CHECK_READY },
     [ 0x03 ] = { cmd_request_sense,                 ALLOW_UA },
     [ 0x12 ] = { cmd_inquiry,                       ALLOW_UA },
-    [ 0x1a ] = { cmd_mode_sense, /* (6) */          0 },
     [ 0x1b ] = { cmd_start_stop_unit,               0 }, /* [1] */
     [ 0x1e ] = { cmd_prevent_allow_medium_removal,  0 },
     [ 0x25 ] = { cmd_read_cdvd_capacity,            CHECK_READY },