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Re: [Qemu-devel] [PATCH v8 0/5] hypertrace: Lightweight guest-to-QEMU tr
From: |
Emilio G. Cota |
Subject: |
Re: [Qemu-devel] [PATCH v8 0/5] hypertrace: Lightweight guest-to-QEMU trace channel |
Date: |
Fri, 25 Aug 2017 20:34:54 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Sun, Jul 30, 2017 at 17:08:18 +0300, Lluís Vilanova wrote:
> The hypertrace channel allows guest code to emit events in QEMU (the host)
> using
> its tracing infrastructure (see "docs/trace.txt"). This works in both 'system'
> and 'user' modes, is architecture-agnostic and introduces minimal noise on the
> guest.
>
> See first commit for a full description, use-cases and an example.
>
> Signed-off-by: Lluís Vilanova <address@hidden>
This would be indeed very useful once TCG instrumentation is in place.
However, I'm not very excited about this being PCI-only and Linux-only for
system mode
I wonder how we could make this work on all hosts -- did you consider using
"magic" instructions? We'd need a different magic instruction for each
guest ISA, but the library would hide that anyway (and the library code
would be the same for user and system modes).
Thanks,
Emilio