Hi,

L4Linux is compiled with -mpreferred-stack-boundary=3, but the "external functions" it calls are usually compiled without this option, so defaults to 16 bytes alignment. This causes potential unaligned memory access if the compiler choose to generate instructions like movdqa.

QEMU without kvm seems to just let this pass, but with kvm enabled, this could generate a GP.

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Regards
Yuxuan Shui