[Qemu-devel] qemu3.0.0: Linux on non x86 CPUs run x86 executable

[Qemu-devel] qemu3.0.0: Linux on non x86 CPUs run x86 executable

[wj193102]

Hi, everyone.
       When I have installed the QEMU3.0.0 in the Linux on non X86 CPUS, I want to use user space emulator to run X86 executable. So I get the document from the QEMU web page (QEMU document) .
I find the section 5.3 and read the content. But I have some questions in the following:
(1)I can't understand the content: "On non x86 CPUs, you need first to download at least an x86 glibc (qemu-runtime-i386-XXX-.tar.gz on the QEMU web page). Ensure that LD_LIBRARY_PATH is not set:
unset LD_LIBRARY_PATH". How I get the X86 glibc? And How to use it? Compiling and installing it in the Linux on non X86 CPUS or not?
(2) I also haven't understood the content:"Then you can launch the precompiled ls x86 executable: qemu-i386 tests/i386/ls". The file of "ls x86 executable" is in the any Linux from the path "/bin/ls"  on the X86 CPUS. Is that right?
Please help me to resolve these questions. Thanks very much.

Re: [Qemu-devel] qemu3.0.0: Linux on non x86 CPUs run x86 executable

[Alex Bennée]

wj193102 <wj193102@163.com> writes:

> Hi, everyone.
>        When I have installed the QEMU3.0.0 in the Linux on non X86 CPUS, I want to use user space emulator to run X86 executable. So I get the document from the QEMU web page (QEMU document) .
> I find the section 5.3 and read the content. But I have some questions in the following:
> (1)I can't understand the content: "On non x86 CPUs, you need first to download at least an x86 glibc (qemu-runtime-i386-XXX-.tar.gz on the QEMU web page). Ensure that LD_LIBRARY_PATH is not set:
> unset LD_LIBRARY_PATH". How I get the X86 glibc? And How to use it?
>        Compiling and installing it in the Linux on non X86 CPUS or
>        not?

The usual way is to create a chroot and install some x86 distro in
there so that it can provide the requisite bits and pieces. The details
vary depending on what chroot you want to setup.

I personally tend to use Debian as it has excellent architecture
support. If you have a working docker setup you can even host your x86
userspace in a docker container which simplifies some aspects.


> (2) I also haven't understood the content:"Then you can launch the
> precompiled ls x86 executable: qemu-i386 tests/i386/ls". The file of
> "ls x86 executable" is in the any Linux from the path "/bin/ls"  on
> the X86 CPUS. Is that right?

Yes. The very simplest case is a statically compiled binaries as you
then don't need to worry about jumping hoops to get the dynamic linker
working.

> Please help me to resolve these questions. Thanks very much.

If you just want to prove you have a working x86 emulation you can just
build the tcg test cases:

cd i386-linux-user
make guest-tests
./qemu-i386 ./tests/linux-test

--
Alex Bennée