diff --git a/pkgs/os-specific/linux/kvm/57.nix b/pkgs/os-specific/linux/kvm/57.nix
index 8b25a9a6ae32..ccbd2d353b12 100644
--- a/pkgs/os-specific/linux/kvm/57.nix
+++ b/pkgs/os-specific/linux/kvm/57.nix
@@ -10,6 +10,11 @@ stdenv.mkDerivation {
     sha256 = "016h5pf59fyz7skzsaprii2mdpxpb8hfnnr1w475qcfyy6ccr9r0";
   };
 
+  patches = [
+    # Allow setting the path to Samba through $QEMU_SMBD_COMMAND.
+    ./smbd-path.patch
+  ];
+
   configureFlags = "--with-patched-kernel --kerneldir=${kernelHeaders}";
 
   # e2fsprogs is needed for libuuid.
diff --git a/pkgs/os-specific/linux/kvm/smbd-path.patch b/pkgs/os-specific/linux/kvm/smbd-path.patch
new file mode 100644
index 000000000000..45e9a4bacced
--- /dev/null
+++ b/pkgs/os-specific/linux/kvm/smbd-path.patch
@@ -0,0 +1,26 @@
+diff -rc kvm-57-orig/qemu/vl.c kvm-57/qemu/vl.c
+*** kvm-57-orig/qemu/vl.c	2007-12-18 16:57:46.000000000 +0100
+--- kvm-57/qemu/vl.c	2008-03-11 16:17:26.000000000 +0100
+***************
+*** 3865,3872 ****
+      fclose(f);
+      atexit(smb_exit);
+  
+      snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -s %s",
+!              SMBD_COMMAND, smb_conf);
+  
+      slirp_add_exec(0, smb_cmdline, 4, 139);
+  }
+--- 3865,3875 ----
+      fclose(f);
+      atexit(smb_exit);
+  
++     char *smbd_command = getenv("QEMU_SMBD_COMMAND");
++     if (!smbd_command) smbd_command = SMBD_COMMAND;
++ 
+      snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -s %s",
+!              smbd_command, smb_conf);
+  
+      slirp_add_exec(0, smb_cmdline, 4, 139);
+  }
+Only in kvm-57/qemu: vl.c~