Re: Tracing KVM with Systemtap

Rayson Ho
2010-09-22T12:42:37Z

On Wed, 2010-09-22 at 13:33 +0100, Stefan Hajnoczi wrote:
> KVM does not generate code. Almost all the "emulation" code in the
> source tree is part of the Tiny Code Generator (TCG) used when KVM is
> not enabled (e.g. to emulate an ARM board on an x86-64 host).

Thanks, that's what I thought too. Otherwise it would be really slow to
run KVM :)

But if KVM is not used, and QEMU host & guest are running on the same
architecture, is TCG off? (Hmm, I guess I can find that answer myself by
reading the code).

Stefan, are you accepting patches? If so, I will create a patch with the
Systemtap framework & other probes.

Rayson

>
> If you follow the life-cycle in vl.c it will take you through cpus.c
> and into kvm-all.c:kvm_cpu_exec(). Note that the details differ
> slightly between qemu.git and qemu-kvm.git, and I have described
> qemu.git.
>
> Stefan
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