[BUG] Qemu VM : arm64 OK, x86+KVM+AVX2 OK , x86+KVM KO (hangs forever 100% CPU) , x86 KO (crashes)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude code does not install in Qemu x86+KVM, or Qemu x86 without KVM with Debian 13 Trixie or Ubuntu 20.04 Focal

What Should Happen?

Claude code should install.

Error Messages/Logs

Steps to Reproduce

Download Debian stable (13 Trixie) cloud generic image for x86_64

wget https://cloud.debian.org/images/cloud/trixie/latest/debian-13-generic-amd64.qcow2

resize qemu img, configure ssh, run qemu x86 + KVM, ssh login

debian@localhost:~$ curl -fsSL https://claude.ai/install.sh | bash
Setting up Claude Code...

CPU 100% hangs forever (after the curl+sha256sum in the script), I have to send SIGTERM (contrary to #83624 that says it's irresponsive to SIGTERM)

if I do with qemu x86 without KVM, it's worse

debian@localhost:~$ curl -fsSL https://claude.ai/install.sh | bash
Setting up Claude Code...
bash: line 183:   946 Illegal instruction     "$binary_path" install ${TARGET:+"$TARGET"}
Installation was killed before it could finish (exit code 132).

if I run with arm64 (take the same Debian 13 Trixie Stable but for arm64), I can install Claude Code.

debian@localhost:~$ curl -fsSL https://claude.ai/install.sh | bash
Setting up Claude Code...

✔ Claude Code successfully installed!

  Version: 2.1.240

  Location: ~/.local/bin/claude


  Next: Run claude --help to get started

⚠ Setup notes:
  ● Native installation exists but ~/.local/bin is not in your PATH. Run:

    echo 'export PATH="$HOME/.local/bin:$PATH"' >> ~/.bashrc && source ~/.bashrc


✅ Installation complete!

Claude Model

_No response_

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.240

Platform

Other

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

sorry if its already known / you are working on it...

there are tons of Issues (14370...), several CPU 100% in virtualized env issues have already been opened, closed, ...

it's my first time ever with vibe-blabla-agentic-blabla-AI so it's a bit disappointing...

tell me how I can help