Re: [PATCH 08/16] tracetool: Add Rust format support

[Paolo Bonzini <pbonzini@redhat.com>]

On 9/25/25 17:09, Stefan Hajnoczi wrote:
> On Thu, Sep 25, 2025 at 8:40 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>> No problem---in fact I have now realized that, for systemtap, I have to
>> ensure that the semaphore is shared between C and Rust!
> 
> Is anyone working on the DTrace support? If not, I'll keep it in mind
> in case I get some time over the next few weeks.
No, the plan was to use the probe-rs crate, which is almost trivial 
except that it does not support the shared semaphore.

For the shared semaphore probe-rs needs modifications.  It's also 
possible to just import its single file with magic asm[1] into QEMU's 
trace crate and modify it as needed; and contribute the changes upstream 
later.

There is also the usdt crate, which recently grew support for systemtap 
SDT as well.  It takes a much more complex approach and has many 
dependencies, as it almost completely reimplements the dtrace compiler. 
It may be interesting for the future since it is more portable, but for 
the time being I'd stick with the lower-level probe-rs.

Paolo

[1] 
https://github.com/bonzini/probe-rs/blob/extern-semaphore/src/platform/systemtap.rs