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Re: [Qemu-devel] [PATCH v4 00/20] instrument: Add basic event instrument
From: |
Emilio G. Cota |
Subject: |
Re: [Qemu-devel] [PATCH v4 00/20] instrument: Add basic event instrumentation |
Date: |
Thu, 7 Sep 2017 10:21:52 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Thu, Sep 07, 2017 at 12:58:05 +0200, Markus Armbruster wrote:
> Lluís Vilanova <address@hidden> writes:
>
> > This series adds an API to add instrumentation events.
> >
> > It also provides additional APIs for:
> > * Controlling tracing events
> > * Peek/poke guest memory
> >
> > There's still missing APIs for (can be added in later series?):
> > * Provide something like tracing's per-vCPU trace states (i.e., so that each
> > vCPU can have different instrumentation code). It's still not clear to me
> > if
> > we should extend the per-vCPU bitmap with instrumentation events, or
> > otherwise
> > somehow reuse the bits in tracing events (since they're currently
> > limited).
> > * Peek/poke guest registers
> >
> > The instrumentation code is dynamically loaded as a library into QEMU either
> > when it starts or later using its remote control interfaces.
> >
> > Signed-off-by: Lluís Vilanova <address@hidden>
>
> Taking a step back.
>
> This looks like a way to dynamically load arbitrary code. What
> interfaces can this code use? Your cover letter should answer this.
>
> As long as the answer is "everything the dynamic linker is willing to
> resolve", this series heading nowhere. We can talk about an interface
> for plugins, but "anything goes" is not on the menu.
A simple solution to this is to only export the API symbols by passing
--dynamic-file to the linker -- see patch 2 of the following series for an
example (ELF-only, although I'm pretty sure this can be achieved on Windows
as well):
https://lists.gnu.org/archive/html/qemu-devel/2017-09/msg01446.html
Thanks,
Emilio
- [Qemu-devel] [PATCH v4 15/20] trace: Introduce a proper structure to describe memory accesses, (continued)
- [Qemu-devel] [PATCH v4 15/20] trace: Introduce a proper structure to describe memory accesses, Lluís Vilanova, 2017/09/06
- [Qemu-devel] [PATCH v4 16/20] instrument: Add event 'guest_mem_before_trans', Lluís Vilanova, 2017/09/06
- [Qemu-devel] [PATCH v4 17/20] instrument: Add event 'guest_mem_before_exec', Lluís Vilanova, 2017/09/06
- [Qemu-devel] [PATCH v4 18/20] instrument: Add event 'guest_user_syscall', Lluís Vilanova, 2017/09/06
- [Qemu-devel] [PATCH v4 19/20] instrument: Add event 'guest_user_syscall_ret', Lluís Vilanova, 2017/09/06
- [Qemu-devel] [PATCH v4 20/20] instrument: Add API to manipulate guest memory, Lluís Vilanova, 2017/09/06
- Re: [Qemu-devel] [PATCH v4 00/20] instrument: Add basic event instrumentation, Emilio G. Cota, 2017/09/06
- Re: [Qemu-devel] [PATCH v4 00/20] instrument: Add basic event instrumentation, Markus Armbruster, 2017/09/07
- Re: [Qemu-devel] [PATCH v4 00/20] instrument: Add basic event instrumentation, Markus Armbruster, 2017/09/07
- Re: [Qemu-devel] [PATCH v4 00/20] instrument: Add basic event instrumentation,
Emilio G. Cota <=