Re: [Qemu-devel] Tracing message for mu

[Stefan Hajnoczi]

On Fri, May 25, 2012 at 3:42 AM, Charles.Tsai-蔡清海-研究發展部
<address@hidden> wrote:
> I had a problem to launch the VM using the script that contains the Qemu 
> options. My script used to work before updating the latest Qemu code 
> suggested by Hans. I also tried to latest code from Freedesktop, it still 
> failed to work either.
> Obviously, Qemu was broken somewhere in the code. I did try to check the log 
> file of the Qemu and it seemed to be not quite helpful.
>
> In this case, how do I turn on the Qemu trace to see where the code failed? 
> From the Qemu document, I cannot find anything talking about this. Please 
> give me a suggestion so that I can probe this issue here.

Please provide details when asking for help:
1. The full QEMU command-line used to launch the guest.
2. The exact error message and where it was printed (inside the guest
or by QEMU itself).
3. Which version of QEMU or which git commit you are testing.

Since you mentioned Hans and Freedesktop I guess this has something to
do with SPICE and QXL.

QEMU tracing does not provide much debug info on startup - it's more
useful once the guest is running and you need to understand the I/O
requests and other operations that are going on.  There is a
quickstart guide in docs/tracing.txt if you want to try it.

Stefan