Re: [Qemu-devel] GSoC 2017 Proposal: TCG performance enhancements

[Paolo Bonzini]

On 07/06/2017 14:07, Peter Maydell wrote:
>> My understanding was that adding a public instrumentation interface would add
>> too much code maintenance overhead for a feature that is not in QEMU's core
>> target.
> Well, it depends what you define as our core target :-)
> I think we get quite a lot of users that want some useful ability
> to see what their guest code is doing, and these days (when
> dev board hardware is often very cheap and easily available)

and virtualization is too...

> I think that's a lot of the value that emulation can bring to
> the table. Obviously we would want to try to do it in a way
> that is low-runtime-overhead and is easy to get right for
> people adding/maintaining cpu target frontend code...

Indeed.  I even sometimes use TCG -d in_asm,exec,int for KVM unit tests,
because it's easier to debug them that way :) so introspection ability
is welcome.

Related to this is also Alessandro's work to librarify TCG (he has a
TCG->LLVM backend for example).