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. -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
