Re: [PATCH v1 00/14] OvmfPkg/Virtio: Add APIs to map system physical to device address

[Laszlo Ersek <lersek@redhat.com>]

On 08/12/17 00:22, Brijesh Singh wrote:
> 
> 
> On 08/09/2017 12:56 PM, Laszlo Ersek wrote:
> 
>>>
>>> Sure, I will make the necessary changes in VirtioMmioDeviceLib and try
>>> do the build test but I don't have aarch64 platform to verify at the
>>> runtime.
>>
>> Actually, dependent on your GNU/Linux distribution, it is pretty easy to
>> do on x86_64 too. It comes together from two parts:
>>
>> (1) installing an aarch64 cross compiler
>> (2) installing qemu-system-aarch64 (from source or distro package),
>>      and then either using it directly (from the cmdline) or with the
>>      libvirt toolstack
>>
>> The only "real" difference is that it's going to use TCG and not KVM
>> (software emulation rather than hardware virtualization), so it will be
>> slower, but that's not really a problem if you only care about your VM
>> until the firmware boots the OS :)
>>
>> On Fedora, the cross-compiler (and cross-binutils) packages are built
>> from the following SRPMs:
>>
>>    https://koji.fedoraproject.org/koji/buildinfo?buildID=921790
>>    https://koji.fedoraproject.org/koji/buildinfo?buildID=912429
>>
>> ("cross-gcc", "cross-binutils")
>>
>> Linaro distributes distro-independent cross compilers:
>>
>>    http://www.linaro.org/downloads/
>>
>> Build instructions for ArmVirtQemu, and usage hints for the QEMU command
>> line, can be found in the Linaro Wiki:
>>
>>    https://wiki.linaro.org/LEG/UEFIforQEMU
> 
> v2 is almost ready for review, I have made all the necessary changes in
> VirtioMmioDeviceLib and it builds fine for aarch64 but I am having trouble
> booting the qemu-aarch64 in general. On serial console I see the UEFI debug
> messages but it never reaches to UEFI shell.
> 
> I have been following the steps from 
> https://wiki.linaro.org/LEG/UEFIforQEMU
> 
> qemu-system-aarch64 \
>  -m 1024 \
>  -cpu cortex-a57 \
>  -M virt  \
>  -bios QEMU_EFI.fd \
>  -serial stdio
> 
> I tried this steps with and without my patches and it resulted in the same.
> It seems like I am missing something in the qemu cli, do I need to pass
> special dtb file or something similar ?

The above command line is not right ("-bios"). Please scroll down the
wiki page, to the section heading saying "Using persistent UEFI
variables". There it explains how to pad the images and how to use two
-pflash options. ... Perhaps even that part of the article is a bit
out-of-date now.

Basically, today ArmVirtQemu should be used the same way as OVMF, except
for the padding. The build produces two files:
- QEMU_EFI.fd (fw binary)
- QEMU_VARS.fd (varstore template)

Each should be padded to 64MiB with zeros at the end (write a small
script for that), then use them with two pflash drives similarly to OVMF.

Thanks!
Laszlo

> P.S: the wiki talks about a prebuilt qcow2 image but the link is dead,
> instead
> I downloaded a qcow2 file from Ubuntu repo.
> 
> -Brijesh