diff --git a/README.md b/README.md
index fadd359..8bf6435 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,9 @@ docker run --detach \
   docker.io/hectorm/qemu-reactos:latest
 ```
 
+> [!NOTE]
+> The `--device /dev/kvm` option can only be used on Linux hosts, it can be removed on Windows and macOS hosts at a significant performance penalty.
+
 The instance can be accessed from:
  * **VNC** (`5900/TCP`), without password.
  * **noVNC** (`6080/TCP`), http://127.0.0.1:6080/vnc.html