[fedora-arm] Debugging our kernels under qemu + gdb

[Jon Masters]

On 05/13/2012 04:34 PM, Michael Hope wrote:
> On 12 May 2012 22:12, Richard W.M. Jones <rjones at redhat.com> wrote:
>> On Fri, May 11, 2012 at 01:41:43PM -0700, Brendan Conoboy wrote:
>>> On 05/11/2012 01:04 PM, Richard W.M. Jones wrote:
>>>> Has anyone tried to debug our Fedora/arm kernels under qemu-system-arm?
>>>> (In this case, the host is also arm, but I don't think that matters.)
>>>
>>> Richard,
>>>
>>> FYI, we as of a few hours ago have nearly-official F17-beta images
>>> for versatile express on the following page:
>>>
>>> http://scotland.proximity.on.ca/arm-nightlies/
>>>
>>> There's a link for vexpress and vexpress+x rootfs images.  A second
>>> link provides a kernel, initramfs, and script for starting qemu.
>>> Note that vexpress is much faster than versatile and allows more ram
>>> (1GB). Recommend you try this out!
>>
>> So one issue appears to be lack of PCI support (according to Linaro's
>> notes: https://wiki.linaro.org/PeterMaydell/QemuVersatileExpress).
>>
>> Unfortunately all of the virtio hardware is PCI-based, so it doesn't
>> seem like this is going to work for the virt tools :-(
> 
> Hi Richard.  The plan is to use virtio-mmio and use Device Tree to set
> where the virtio devices are.  virtio-mmio is in the mainline kernel
> and in the queue for QEMU.

Note, we're not using dtb (device tree) yet in the qemu kernel. To do
that properly, we'll need to get a qemu that works with U-Boot, etc. I
know Linaro have put such a combination together, right? Should any of
that be working with upstream bits yet? Brendan mentioned he'd tried
poking briefly at the U-Boot that Linaro put together but it apparently
didn't boot on our qemu (I know upstream was missing e.g. the model
instantiation for the hardware memory controller, etc. in vexpress).

I guess I could/should ping Peter Maydell? Is he the best contact?

Jon.