Re: [PATCH trace-cmd] plugin_kvm: disassemble instructions forkvm_emulate_insn

From: Steven Rostedt
Date: Mon Sep 20 2010 - 14:21:53 EST


On Mon, 2010-09-20 at 11:51 +0200, Avi Kivity wrote:
> On 09/19/2010 04:33 PM, Avi Kivity wrote:
> > Override kvm_emulate_insn formatting to use a disassembler to format
> > the emulated instruction. If a disassembler (udis86) is not available,
> > fall back to showing the instruction bytes in hex.
> >
> > Signed-off-by: Avi Kivity<avi@xxxxxxxxxx>
> > ---
> >
> > Note 1: on top of 'master' with 'trace-cmd-kvm' cherry-picked on top.
> >
> > Note 2: I get output of the form
> >
> > ... kvm_emulate_insn: 0:fffff800010527b5: mov $0x0, 0xfffe00b0CAN'T FIND FIELD "guest_rip"
> >
> > which leads me to believe there is a bug in trace_seq_printf when the input
> > to %s is "".
> >
> >
>
> Note 3: this is not thread safe. If trace-cmd wants to be (or is)
> multithreaded, we need some kind of plugin context that is passed to all
> plugin methods, which is initialized separately for each thread.
>
> Or we can be lazy and use thread local storage.
>

No need, I purposely, made trace-cmd non-threaded. Too much hassles ;-)

-- Steve


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