Re: [edk2-devel] Help with debugging

["Laszlo Ersek" <lersek@redhat.com>]

On 06/11/21 19:06, Ethin Probst wrote:
> Hey all,
> 
> So Leif and I have discussed this at length but I thought I'd reach
> out to all of you for more help.
> 
> I'm having a lot of trouble debugging my UEFI app. Here's how I do things:
> 
> - I load the app using uefi-run
> (https://github.com/Richard-W/uefi-run) like this (from the main EDK
> II directory): uefi-run -b Build/OvmfX64/DEBUG_GCC5/FV/OVMF.fd
> Build/OvmfX64/DEBUG_GCC5/X64/Shell.efi -- -M q35 -m 24G -usb -device
> qemu-xhci -device usb-audio,audiodev=audio -audiodev alsa,id=audio -s
> -debugcon file:../debug.log -global isa-debugcon.iobase=0x402
> -nographic
> Or:
> uefi-run -b Build/OvmfX64/DEBUG_GCC5/FV/OVMF.fd
> Build/OvmfX64/DEBUG_GCC5/X64/Shell.efi -- -M q35 -m 24G -usb -device
> qemu-xhci -device usb-audio,audiodev=audio -audiodev alsa,id=audio -s
> -debugcon stdio -global isa-debugcon.iobase=0x402

Side comment:

OVMF supports virtio-fs, and using virtio-fs could speed up your
develop/build/test cycle.

Assuming your UEFI application does not crash or hang (i.e., assuming it
exits cleanly and you can continue using the same UEFI shell session),
virtio-fs could be a small productivity boost for you, as you wouldn't
have to re-launch QEMU every time.

The idea is to build your application through some platform DSC file as
follows -- note that it need not be an OVMF DSC file, but it may be one,
if you prefer that:

  build -a X64 -b NOOPT -p MyAppPkg/MyApp.dsc -t GCC5 \
    -m MyAppPkg/MyApp/MyApp.inf

You don't need an FDF file for this, just grab the resultant "MyApp.efi"
binary from the Build directory.

Then copy "MyApp.efi" (on the host side) under the virtio-fs root
directory somewhere. When the copy operation completes (on the host
side), just switch your focus to the guest UEFI shell window, and you
can immediately execute the just-built application.

I find using virtio-fs by far the easiest with libvirt, but you can use
it from the bare QEMU command line, too.

https://libvirt.org/kbase/virtiofs.html
https://virtio-fs.gitlab.io/howto-qemu.html

This assumes that your development environment is Linux-based, as the
virtio-fs daemon (which runs in tandem with QEMU on the host) is Linux-only.

Thanks,
Laszlo