readme: temporarily require QEMU 7.1.0

Author: luojia65

README.md

@@ -5,6 +5,12 @@ file and implement simple SBI directly, thus RustSBI provides a bootable ELF fil
 
 ## Try it out!
 
+_Note: we have discovered some issues on incompability by this project with QEMU 7.2.0.
+If you are using this project on QEMU 7.x, it is temporarily required to revert to version 7.1.0.
+You may get some help from documents of package manager software. For example, if you are using Homebrew,
+try this [link](https://shockerli.net/post/homebrew-install-formula-specific-version/).
+We thank to an anonymous contributor for pointing out this issue._
+
 To prepare for environment, you should have Rust compiler and QEMU installed.
 You may install Rust by [rustup](https://rustup.rs) or using vendor provided rustc and cargo packages.
 To install QEMU, your may need to use package manager (e.g. apt, dnf etc.) from system distribution