--- c/hw/i386/multiboot.c
+++ i/hw/i386/multiboot.c
@@ -288,8 +288,7 @@ int load_multiboot(FWCfgState *fw_cfg,
     mbs.offset_mbinfo = mbs.mb_buf_size;
 
     /* Calculate space for cmdlines, bootloader name, and mb_mods */
-    cmdline_len = strlen(kernel_filename) + 1;
-    cmdline_len += strlen(kernel_cmdline) + 1;
+    cmdline_len = strlen(kernel_cmdline) + 1;
     if (initrd_filename) {
         const char *r = initrd_filename;
         cmdline_len += strlen(initrd_filename) + 1;
@@ -327,10 +326,11 @@ int load_multiboot(FWCfgState *fw_cfg,
 
             /* if a space comes after the module filename, treat everything
                after that as parameters */
-            hwaddr c = mb_add_cmdline(&mbs, one_file);
+            hwaddr c = 0;
             next_space = strchr(one_file, ' ');
             if (next_space) {
                 *next_space = '\0';
+                c = mb_add_cmdline(&mbs, next_space + 1);
             }
             mb_debug("multiboot loading module: %s", one_file);
             mb_mod_length = get_image_size(one_file);
@@ -360,10 +360,7 @@ int load_multiboot(FWCfgState *fw_cfg,
     }
 
     /* Commandline support */
-    char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
-    snprintf(kcmdline, sizeof(kcmdline), "%s %s",
-             kernel_filename, kernel_cmdline);
-    stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
+    stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kernel_cmdline));
 
     stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs, bootloader_name));