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Re: [Qemu-devel] Any approach to log the file read/write (I/O data flow)
From: |
Yue Chen |
Subject: |
Re: [Qemu-devel] Any approach to log the file read/write (I/O data flow) like the "-d in_asm" option? |
Date: |
Sun, 3 Jun 2012 16:50:04 -0400 |
I'm doing something like a simple and lightweight REPLAY program out of QEMU, only including CPU, MEMORY, and DISK. I'm implementing it with a shadow CPU (register state), shadow memory(from "pmemsave") and shadow ".img" file (disk).
When I get the "log exec,op"(preferred) or "log exec,in_asm" instruction traces from monitor in whole-system emulation mode, the final step to replay read/write a file to/from the disk seems the "in/ins" and "out/outs" instructions(translated into a CALL instruction in Intermediate Representation of QEMU), which can set DMA and transfer data.
But from the instruction traces, I don't know which location in the ".img" file (disk) has been accessed. (It's also hard to find out which file has been read/written in higher semantics.) Any easy approach to do this? Thanks so much.
On Fri, Jun 1, 2012 at 4:09 AM, Stefan Hajnoczi
<address@hidden> wrote:
On Fri, Jun 1, 2012 at 4:11 AM, Yue Chen <
address@hidden> wrote:
> Any approach to log all the file read/write (I/O data flow) in order,
> together with the instruction traces in QEMU? Thanks.
It sounds like you may be running a *-user target because softmmu
(system emulation) has no knowledge of file I/O inside the guest.
Please give more details of what you're trying to do if this is
incorrect.
It sounds like you want strace together with -d in_asm output. Have
you seen linux-user/strace.c?
Stefan