Re: [Qemu-devel] Trace memory access in guest VM?

[Peter Maydell]

On 30 June 2015 at 10:47, Jun Koi <address@hidden> wrote:
> I am trying to monitor all the memory accesses inside the guest VM running
> on Qemu. I know this is heavy, but this is only the first step of my
> experiments.
>
> To do this, I look at the sample trace in "trace-events" and wondering: is
> it possible to trace all the memory access (read/write) in the guest VM with
> available "memory_region_ops_read" & "memory_region_ops_write" events?

No. You will miss all the fast-path memory accesses, which are
done with custom generated assembly in the TCG backend. In
general QEMU is not designed to support this kind of monitoring
of guest operations.

> I am looking very close to the docs, but there is no information on
> these events.

Trace events are generally intended to assist with debugging
of QEMU itself -- the assumption is that you're sufficiently
familiar with the code to find the information they provide
informative.

thanks
-- PMM