[Qemu-devel] [PATCH] scsi-disk: Inquiry with allocation length of CDB < 36

[Artyom Tarasenko <atar4qemu@googlemail.com>]

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According to SCSI-2 specification,
http://ldkelley.com/SCSI2/SCSI2/SCSI2/SCSI2-08.html#8.2.5 ,
"if the allocation length of the command descriptor block (CDB) is too
small to transfer
all of the parameters, the additional length shall not be adjusted to
reflect the truncation."
The 36 mandatory bytes of response are written to outbuf, and then
only the length requested
in CDB is transferred.

Signed-off-by: Artyom Tarasenko <atar4qemu@gmail.com>
---
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 2a9268a..1a7487e 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -5,6 +5,12 @@
  * Based on code by Fabrice Bellard
  *
  * Written by Paul Brook
+ * Modifications:
+ *  2009-Oct-26 Artyom Tarasenko : implemented stamdard inquiry for the case
+ *                                 when the allocation length of CDB is smaller
+ *                                 than 36.
+ *  2009-Oct-13 Artyom Tarasenko : implemented the block descriptor in the
+ *                                 MODE SENSE response.
  *
  * This code is licenced under the LGPL.
  *
@@ -576,11 +582,6 @@ static int32_t scsi_send_command(SCSIDevice *d,
uint32_t tag,
                      "is less than 5\n", len);
                 goto fail;
             }
-
-            if (len < 36) {
-                BADF("Error: Inquiry (STANDARD) buffer size %d "
-                     "is less than 36 (TODO: only 5 required)\n", len);
-            }
         }

         if(len > SCSI_MAX_INQUIRY_LEN)
@@ -604,7 +605,13 @@ static int32_t scsi_send_command(SCSIDevice *d,
uint32_t tag,
            Some later commands are also implemented. */
        outbuf[2] = 3;
        outbuf[3] = 2; /* Format 2 */
-       outbuf[4] = len - 5; /* Additional Length = (Len - 1) - 4 */
+       if (len > 36) {
+           outbuf[4] = len - 5; /* Additional Length = (Len - 1) - 4 */
+       } else {
+              /* If the allocation length of CDB is too small, the
additional length
+                 is not adjusted */
+           outbuf[4] = 36 - 5;
+       }
         /* Sync data transfer and TCQ.  */
         outbuf[7] = 0x10 | (r->bus->tcq ? 0x02 : 0);
        r->iov.iov_len = len;

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Signed-off-by: Artyom Tarasenko <atar4qemu@gmail.com>
---
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 2a9268a..1a7487e 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -5,6 +5,12 @@
  * Based on code by Fabrice Bellard
  *
  * Written by Paul Brook
+ * Modifications:
+ *  2009-Oct-26 Artyom Tarasenko : implemented stamdard inquiry for the case
+ *                                 when the allocation length of CDB is smaller
+ *                                 than 36.
+ *  2009-Oct-13 Artyom Tarasenko : implemented the block descriptor in the 
+ *                                 MODE SENSE response.
  *
  * This code is licenced under the LGPL.
  *
@@ -576,11 +582,6 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
                      "is less than 5\n", len);
                 goto fail;
             }
-
-            if (len < 36) {
-                BADF("Error: Inquiry (STANDARD) buffer size %d "
-                     "is less than 36 (TODO: only 5 required)\n", len);
-            }
         }
 
         if(len > SCSI_MAX_INQUIRY_LEN)
@@ -604,7 +605,13 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
            Some later commands are also implemented. */
 	outbuf[2] = 3;
 	outbuf[3] = 2; /* Format 2 */
-	outbuf[4] = len - 5; /* Additional Length = (Len - 1) - 4 */
+	if (len > 36) {
+	    outbuf[4] = len - 5; /* Additional Length = (Len - 1) - 4 */
+	} else {
+              /* If the allocation length of CDB is too small, the additional length
+                 is not adjusted */  
+	    outbuf[4] = 36 - 5;
+	}
         /* Sync data transfer and TCQ.  */
         outbuf[7] = 0x10 | (r->bus->tcq ? 0x02 : 0);
 	r->iov.iov_len = len;