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

[Richard W.M. Jones]

On Mon, May 14, 2012 at 12:57:09AM -0400, Jon Masters wrote:
> 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).

There's something quite broken about our qemu package.  I haven't
looked at what it is yet, but at the moment I'm using qemu built from
upstream git for all testing.  I'll try to look at what's going on
with the qemu package later.

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

Rich.

-- 
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