diff --git a/blockdev.c b/blockdev.c
index 8c51e6e..a1e6394 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -21,6 +21,83 @@
 
 static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);
 
+static BlockDriver *parse_block_format(const char *val)
+{
+    BlockDriver *drv = bdrv_find_whitelisted_format(val);
+    if (!drv) {
+        qerror_report(QERR_INVALID_PARAMETER_VALUE,
+                      "format", "a block driver name");
+        return NULL;
+    }
+    return drv;
+}
+
+static int parse_block_error_action(const char *val, int is_read)
+{
+    if (!val) {
+        return is_read ? BLOCK_ERR_REPORT : BLOCK_ERR_STOP_ENOSPC;
+    } else if (!strcmp(val, "ignore")) {
+        return BLOCK_ERR_IGNORE;
+    } else if (!is_read && !strcmp(val, "enospc")) {
+        return BLOCK_ERR_STOP_ENOSPC;
+    } else if (!strcmp(val, "stop")) {
+        return BLOCK_ERR_STOP_ANY;
+    } else if (!strcmp(val, "report")) {
+        return BLOCK_ERR_REPORT;
+    } else {
+        if (is_read) {
+            qerror_report(QERR_INVALID_PARAMETER_VALUE, "rerror",
+                          "ignore, report, stop");
+        } else {
+            qerror_report(QERR_INVALID_PARAMETER_VALUE, "werror",
+                          "enospc, ignore, stop or report");
+        }
+        return -1;
+    }
+}
+
+static int parse_block_cache(const char *val)
+{
+    if (!val) {
+        return 0;
+    } else if (!strcmp(val, "off") || !strcmp(val, "none")) {
+        return BDRV_O_NOCACHE;
+    } else if (!strcmp(val, "writeback")) {
+        return BDRV_O_CACHE_WB;
+    } else if (!strcmp(val, "unsafe")) {
+        return BDRV_O_CACHE_WB;
+        return BDRV_O_NO_FLUSH;
+    } else if (!strcmp(val, "writethrough")) {
+        return 0;
+    } else {
+        qerror_report(QERR_INVALID_PARAMETER_VALUE, "cache",
+            "none, unsafe, writeback or writethrough");
+        return -1;
+    }
+}
+
+static int parse_block_aio(const char *val)
+{
+    if (!val) {
+        return 0;
+#ifdef CONFIG_LINUX_AIO
+    } else if (!strcmp(val, "native")) {
+        return BDRV_O_NATIVE_AIO;
+#endif
+    } else if (!strcmp(val, "threads")) {
+        return 0;
+    } else {
+        qerror_report(QERR_INVALID_PARAMETER_VALUE, "aio",
+#ifdef CONFIG_LINUX_AIO
+                      "native or threads"
+#else
+                      "threads"
+#endif
+            );
+        return -1;
+    }
+}
+
 static int blockdev_del_dinfo(BlockDriverState *bs)
 {
     DriveInfo *dinfo, *next_dinfo;
@@ -126,23 +203,6 @@ void drive_uninit(DriveInfo *dinfo)
     qemu_free(dinfo);
 }
 
-static int parse_block_error_action(const char *buf, int is_read)
-{
-    if (!strcmp(buf, "ignore")) {
-        return BLOCK_ERR_IGNORE;
-    } else if (!is_read && !strcmp(buf, "enospc")) {
-        return BLOCK_ERR_STOP_ENOSPC;
-    } else if (!strcmp(buf, "stop")) {
-        return BLOCK_ERR_STOP_ANY;
-    } else if (!strcmp(buf, "report")) {
-        return BLOCK_ERR_REPORT;
-    } else {
-        fprintf(stderr, "qemu: '%s' invalid %s error action\n",
-            buf, is_read ? "read" : "write");
-        return -1;
-    }
-}
-
 DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
 {
     const char *buf;
@@ -280,34 +340,17 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
 	}
     }
 
-    if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
-        if (!strcmp(buf, "off") || !strcmp(buf, "none")) {
-            bdrv_flags |= BDRV_O_NOCACHE;
-        } else if (!strcmp(buf, "writeback")) {
-            bdrv_flags |= BDRV_O_CACHE_WB;
-        } else if (!strcmp(buf, "unsafe")) {
-            bdrv_flags |= BDRV_O_CACHE_WB;
-            bdrv_flags |= BDRV_O_NO_FLUSH;
-        } else if (!strcmp(buf, "writethrough")) {
-            /* this is the default */
-        } else {
-           fprintf(stderr, "qemu: invalid cache option\n");
-           return NULL;
-        }
+    ret = parse_block_cache(qemu_opt_get(opts, "cache"));
+    if (ret < 0) {
+        return NULL;
     }
+    bdrv_flags |= ret;
 
-#ifdef CONFIG_LINUX_AIO
-    if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
-        if (!strcmp(buf, "native")) {
-            bdrv_flags |= BDRV_O_NATIVE_AIO;
-        } else if (!strcmp(buf, "threads")) {
-            /* this is the default */
-        } else {
-           fprintf(stderr, "qemu: invalid aio option\n");
-           return NULL;
-        }
+    ret = parse_block_aio(qemu_opt_get(opts, "aio"));
+    if (ret < 0) {
+        return NULL;
     }
-#endif
+    bdrv_flags |= ret;
 
     if ((buf = qemu_opt_get(opts, "format")) != NULL) {
        if (strcmp(buf, "?") == 0) {
@@ -316,9 +359,8 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
             fprintf(stderr, "\n");
 	    return NULL;
         }
-        drv = bdrv_find_whitelisted_format(buf);
+        drv = parse_block_format(buf);
         if (!drv) {
-            fprintf(stderr, "qemu: '%s' invalid format\n", buf);
             return NULL;
         }
     }
