On 09/03/2014 11:38 AM, Christoffer Dall wrote:
On Wed, Sep 3, 2014 at 12:19 AM, Zbigniew Bodek <zbb@xxxxxxxxxxxx> wrote:
2014-09-02 9:26 GMT+02:00 Diana Craciun <diana.craciun@xxxxxxxxxxxxx>:
On 09/01/2014 05:34 PM, Christoffer Dall wrote:
On Mon, Sep 01, 2014 at 12:34:09PM +0200, Zbigniew Bodek wrote:
2014-09-01 12:16 GMT+02:00 Christoffer Dall
<christoffer.dall@xxxxxxxxxx>:
On Monday, September 1, 2014, Zbigniew Bodek <zbb@xxxxxxxxxxxx> wrote:
2014-09-01 11:56 GMT+02:00 Zbigniew Bodek <zbb@xxxxxxxxxxxx>:
Hello Christopher,
Please check out my answers in-line.
Best regards
zbb
2014-09-01 11:00 GMT+02:00 Christoffer Dall
<christoffer.dall@xxxxxxxxxx>:
On Tue, Aug 26, 2014 at 12:17:17PM +0200, Zbigniew Bodek wrote:
2014-08-25 21:30 GMT+02:00 Joel Schopp <joel.schopp@xxxxxxx>:
On 08/25/2014 02:03 PM, Peter Maydell wrote:
On 25 August 2014 19:49, Joel Schopp <joel.schopp@xxxxxxx> wrote:
I'm guessing that the patches Peter posted recently might have a
positive effect on breakpoints and debugging with gdb.
https://lists.nongnu.org/archive/html/qemu-devel/2014-08/msg01291.html
No, those relate to running a GDB inside the QEMU TCG guest,
and won't affect an external gdb. What Zbigniew wants to do
is use the QEMU gdbstub to debug the whole guest. For
breakpoints to work in that when KVM is enabled requires
implementing support for breakpoints and the debug
interface in KVM and then the corresponding support for it
in QEMU. This is on our todo list (those with cards.linaro.org
access can find it as VIRT-116) but I don't think anybody's
working on it right now.
Thanks for the clarification. So many todos, so little time.
Hello again,
Thank you all very much for your answers.
Actually I use qemu with GDB as described here (-s -S, etc.), I've
just posted the simplest command that I use to trigger the bug.
So regarding your answers I would like to ask for some more
clarification:
* Has anyone encountered/reproduce this problem on your ARM host?
* Any suggestion where to look in the KVM source for these kind of
problems?
* Maybe there is some unstable feature that I could disable in
host/guest to narrow this issue?
Just checking: Are you compiling any of your kernels in Thumb-2
mode?
I believe the 5250 has a hardware bug with Thumb-2 and Hyp mode.
No, I am not compiling my kernels in Thumb-2 mode.
Continuous reboots seems to work fine on my TC2. I can try giving it
a
test on an Arndale some time in the near future. Which kernel
version
(exact commit) are you using for your host and guest?
I used v3.17-rc1 which is: 7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9
Ok, and when you say reboot, do you mean executing 'reboot' in the guest
or
are you shutting down the qemu process completely and starting a new VM?
Do
you run any specific workload in the VM?
I mean to execute 'reboot' command in the guest system, not exit and
reset qemu process.
But the issues I encounter can be also triggered when I execute guest
machine for the first time (so without previous reboots). It is
totally random behavior.
I am not running anything in the VM. Just login to busybox/Ubuntu and
reboot.
I just had a loop running on TC2 for hours and it works fine. Likely to
be some specific issue with the Arndale board, I'll have a look when I
have a chance to configure my board.
I saw this behaviour on Arndale board also. When I saw it I was running an
older kernel so it is not something new.
Diana
Hello,
Thanks for the confirmation. I've also tried older kernel and the same
problems appear.
Does anyone have any clues which areas to investigate in order to debug this?
Thank you all for your help.
You should enable the KVM dynamic tracepoints in your host and figure
out where the guest gets stuck and if there's any consistency between
when it happens.
I remember that I enabled tracepoints but it was inconsistent, the
problem did not happened in the same place. Also I have noticed that
when it returned from guest the guest PC was wrong. It had strange
values of 0xc, 0xf...
Diana
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