topic Re: P4080DS kernel debugging with hypervisor in P-Series

P4080DS kernel debugging with hypervisor

avasu — Wed, 20 Feb 2013 21:08:14 GMT

Hello,

I would like to debug the kernel in the presence of Topaz hypervisor.

I enabled kernel debugging and I compiled the images. I followed "QorIQ debbuging user's guide" and exactly performed the steps for QorIQ debugging, in the presence of hypervisor. The QorIQ debug module does not get loaded. Does hypervisor intervene when I try to "modprobe qoriq-dbg" in the kernel?

Should I change hypervisor configuration and rebuild embedded-hv so that the hypervisor lets the kernel access the registers that I am interested in?

It would be really great if someone has already worked on something similar and can clear my doubts.

I am able to debug the kernel when the kernel is standalone without any partitions and hypervisor.

Thanks,

A Vasu

Re: P4080DS kernel debugging with hypervisor

laurentiutudor — Fri, 22 Feb 2013 11:32:03 GMT

Hi Vasu,

Few comments below ...

I enabled kernel debugging and I compiled the images. I followed "QorIQ debbuging user's guide" and exactly performed the steps for QorIQ debugging, in the presence of hypervisor. The QorIQ debug module does not get loaded. Does hypervisor intervene when I try to "modprobe qoriq-dbg" in the kernel?

There shouldn't be any interaction between hypervisor and the module.

Should I change hypervisor configuration and rebuild embedded-hv so that the hypervisor lets the kernel access the registers that I am interested in?

The debug resources (registers and interrupt) are given to the guest by default so you shouldn't need to change the hypervisor config. Unless you use a very old hypervisor version that by default allocated the debug resources to the hypervisor or, by chance, you have a "guest-debug- disable" property in your partition definition node in the configuration.

Can you explore other options such as using gdb with the gdb-stub included in Topaz (see Embedded Hypervisor User's Manual, Apendix A for details)?

What version of hypervisor are you using?

Can you share the config file?

---

HTH, Laurentiu

Re: P4080DS kernel debugging with hypervisor

avasu — Thu, 18 Apr 2013 22:18:02 GMT

Hello,

Sorry about the late response. I do not have a "guest-debug-disable' property defined in the partition definition node. I am attaching the hypervisor and kernel configuration device trees.

Here are the versions of the hypervisor and kernel.

Hypervisor version:

=====================

Freescale Embedded Hypervisor version 1.2-003

Linux version:

================

Linux p4080ds 3.0.34-rt55-02404-g1a39570 #1 SMP PREEMPT RT Wed Feb 27 21:38:39 CST 2013 ppc GNU/Linux

Please let me know if I am going wrong somewhere.

Thanks,

A vasu