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Re: [Qemu-devel] Trace memory access in guest VM?
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] Trace memory access in guest VM? |
Date: |
Tue, 30 Jun 2015 11:01:07 +0100 |
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