scsi: Update sense code handling

The SCSI spec has a quite detailed list of sense codes available.
It even mandates the use of specific ones for some failure cases.
The current implementation just has one type of generic error
which is actually a violation of the spec in certain cases.
This patch introduces various predefined sense codes to have the
sense code reporting more in line with the spec.

On top of Hannes's patch I fixed the reply to REQUEST SENSE commands
with DESC=0 and a small (<18) length.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 90 insertions, 1 deletions

diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index fd1d60f..d322f3a 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -154,7 +154,7 @@ void scsi_req_enqueue(SCSIRequest *req)
     QTAILQ_INSERT_TAIL(&req->dev->requests, req, next);
 }
 
-void scsi_req_dequeue(SCSIRequest *req)
+static void scsi_req_dequeue(SCSIRequest *req)
 {
     trace_scsi_req_dequeue(req->dev->id, req->lun, req->tag);
     if (req->enqueued) {
@@ -391,6 +391,95 @@ int scsi_req_parse(SCSIRequest *req, uint8_t *buf)
     return 0;
 }
 
+/*
+ * Predefined sense codes
+ */
+
+/* No sense data available */
+const struct SCSISense sense_code_NO_SENSE = {
+    .key = NO_SENSE , .asc = 0x00 , .ascq = 0x00
+};
+
+/* LUN not ready, Manual intervention required */
+const struct SCSISense sense_code_LUN_NOT_READY = {
+    .key = NOT_READY, .asc = 0x04, .ascq = 0x03
+};
+
+/* LUN not ready, Medium not present */
+const struct SCSISense sense_code_NO_MEDIUM = {
+    .key = NOT_READY, .asc = 0x3a, .ascq = 0x00
+};
+
+/* Hardware error, internal target failure */
+const struct SCSISense sense_code_TARGET_FAILURE = {
+    .key = HARDWARE_ERROR, .asc = 0x44, .ascq = 0x00
+};
+
+/* Illegal request, invalid command operation code */
+const struct SCSISense sense_code_INVALID_OPCODE = {
+    .key = ILLEGAL_REQUEST, .asc = 0x20, .ascq = 0x00
+};
+
+/* Illegal request, LBA out of range */
+const struct SCSISense sense_code_LBA_OUT_OF_RANGE = {
+    .key = ILLEGAL_REQUEST, .asc = 0x21, .ascq = 0x00
+};
+
+/* Illegal request, Invalid field in CDB */
+const struct SCSISense sense_code_INVALID_FIELD = {
+    .key = ILLEGAL_REQUEST, .asc = 0x24, .ascq = 0x00
+};
+
+/* Illegal request, LUN not supported */
+const struct SCSISense sense_code_LUN_NOT_SUPPORTED = {
+    .key = ILLEGAL_REQUEST, .asc = 0x25, .ascq = 0x00
+};
+
+/* Command aborted, I/O process terminated */
+const struct SCSISense sense_code_IO_ERROR = {
+    .key = ABORTED_COMMAND, .asc = 0x00, .ascq = 0x06
+};
+
+/* Command aborted, I_T Nexus loss occurred */
+const struct SCSISense sense_code_I_T_NEXUS_LOSS = {
+    .key = ABORTED_COMMAND, .asc = 0x29, .ascq = 0x07
+};
+
+/* Command aborted, Logical Unit failure */
+const struct SCSISense sense_code_LUN_FAILURE = {
+    .key = ABORTED_COMMAND, .asc = 0x3e, .ascq = 0x01
+};
+
+/*
+ * scsi_build_sense
+ *
+ * Build a sense buffer
+ */
+int scsi_build_sense(SCSISense sense, uint8_t *buf, int len, int fixed)
+{
+    if (!fixed && len < 8) {
+        return 0;
+    }
+
+    memset(buf, 0, len);
+    if (fixed) {
+        /* Return fixed format sense buffer */
+        buf[0] = 0xf0;
+        buf[2] = sense.key;
+        buf[7] = 7;
+        buf[12] = sense.asc;
+        buf[13] = sense.ascq;
+        return MIN(len, 18);
+    } else {
+        /* Return descriptor format sense buffer */
+        buf[0] = 0x72;
+        buf[1] = sense.key;
+        buf[2] = sense.asc;
+        buf[3] = sense.ascq;
+        return 8;
+    }
+}
+
 static const char *scsi_command_name(uint8_t cmd)
 {
     static const char *names[] = {