scsi-disk: Fail medium writes with proper sense for readonly LUNs

Add sense code for DATA_PROTECT/WRITE_PROTECTED and return this error
for any WRITE*/WRITE_VERIFY* calls if the device is readonly=on,
i.e. write-protected
Signed-off-by: NRonnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi-bus.c

@@ -1182,6 +1182,11 @@ const struct SCSISense sense_code_DEVICE_INTERNAL_RESET = {
     .key = UNIT_ATTENTION, .asc = 0x29, .ascq = 0x04
 };
 
+/* Data Protection, Write Protected */
+const struct SCSISense sense_code_WRITE_PROTECTED = {
+    .key = DATA_PROTECT, .asc = 0x27, .ascq = 0x00
+};
+
 /*
  * scsi_build_sense
  *

hw/scsi-disk.c

@@ -1702,6 +1702,10 @@ static int32_t scsi_disk_emulate_command(SCSIRequest *req, uint8_t *buf)
     case WRITE_SAME_16:
         nb_sectors = ldl_be_p(&req->cmd.buf[10]) & 0xffffffffULL;
     write_same:
+        if (bdrv_is_read_only(s->qdev.conf.bs)) {
+            scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED));
+            return 0;
+        }
         if (r->req.cmd.lba > s->qdev.max_lba) {
             goto illegal_lba;
         }
@@ -1784,9 +1788,6 @@ 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);
         break;
-    case VERIFY_10:
-    case VERIFY_12:
-    case VERIFY_16:
     case WRITE_6:
     case WRITE_10:
     case WRITE_12:
@@ -1794,6 +1795,14 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf)
     case WRITE_VERIFY_10:
     case WRITE_VERIFY_12:
     case WRITE_VERIFY_16:
+        if (bdrv_is_read_only(s->qdev.conf.bs)) {
+            scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED));
+            return 0;
+        }
+        /* fallthrough */
+    case VERIFY_10:
+    case VERIFY_12:
+    case VERIFY_16:
         len = r->req.cmd.xfer / s->qdev.blocksize;
         DPRINTF("Write %s(sector %" PRId64 ", count %d)\n",
                 (command & 0xe) == 0xe ? "And Verify " : "",

hw/scsi.h

@@ -208,6 +208,8 @@ extern const struct SCSISense sense_code_MEDIUM_CHANGED;
 extern const struct SCSISense sense_code_REPORTED_LUNS_CHANGED;
 /* Unit attention, Device internal reset */
 extern const struct SCSISense sense_code_DEVICE_INTERNAL_RESET;
+/* Data Protection, Write Protected */
+extern const struct SCSISense sense_code_WRITE_PROTECTED;
 
 #define SENSE_CODE(x) sense_code_ ## x