Re: [Qemu-devel] Maintainers, please tell us how to boot your machines!

[Andrey Smirnov <andrew.smirnov@gmail.com>]

On Tue, Mar 12, 2019 at 10:36 AM Markus Armbruster <armbru@redhat.com> wrote:
>
> Dear board code maintainers,
>
> This is a (rather late) follow-up to the last QEMU summit.  Minutes[*]:
>
>  * Deprecating unmaintained features (devices, targets, backends) in QEMU
>
>    QEMU has a mechanism to deprecate features but there remains a lot of
>    old unmaintained code.  Refactoring is hindered by untested legacy
>    code, so there is a desire to deprecate unmaintained features more
>    often.
>
>    [...]
>
>    We should require at least a minimal test for each board; if nobody
>    cares enough to come up with one, that board should be deprecated.
>
>    [...]
>
>    Also see the qemu-devel discussion about deprecating code:
>    https://lists.nongnu.org/archive/html/qemu-devel/2018-10/msg05828.html.
>
> That's a link to "Minutes of KVM Forum BoF on deprecating stuff".
> Quote:
>
>  * One obvious class of candidates for removal is machines we don't know
>    how to boot, or can't boot, say because we lack required firmware
>    and/or OS.
>
>    Of course, "can boot" should be an automated test.  As a first step
>    towards that, we should at least document how to boot each machine.
>    We're going to ask machine maintainers to do that.
>
> Let's get going on this.
>
> I gathered the machine types, mapped them to source files, which I fed
> to get_maintainer.pl.  Results are appended.  If you're cc'ed,
> MAINTAINERS fingers you for at least one machine type's source file.
> Please tell us for all of them how to to a "meaningful" boot test.
>
> For now, what's "meaningful" is entirely up to you.  Booting Linux
> certainly is.
>
> Make sure to include a complete QEMU command line.  If your QEMU command
> line requires resources beyond the QEMU source tree and what we build
> from it, please detail them, and provide download URLs as far as
> possible.
>
> Goals for this exercise:
>
> * Gather information we need to cover more machines in our automated
>   testing.
>
>   Related work:
>   [PATCH v4 00/19] Acceptance Tests: target architecture support
>   Message-Id: <20190312121150.8638-1-crosa@redhat.com>
>   https://lists.gnu.org/archive/html/qemu-devel/2019-03/msg03881.html
>
> * Maybe identify a few machines we don't know how to boot anymore.
>
> Thanks in advance for your help!
>
>
>
> Machines with at least one maintainer:
>
>
>     = hw/arm/mcimx7d-sabre.c =
>     Peter Maydell <peter.maydell@linaro.org> (odd fixer:MCIMX7D SABRE / i...)
>     Andrey Smirnov <andrew.smirnov@gmail.com> (reviewer:MCIMX7D SABRE / i...)
>     qemu-arm@nongnu.org (open list:MCIMX7D SABRE / i...)
>

Sorry I am late to this party. I haven't used i.MX7 emulation in a
while and things didn't go smoothly out of the box, so I had to create
a number of fixes (submitted to the ML).

I use Linux kernel built using Buildroot for validation. Buildroot
should have a default i.MX7 Sabred SD configuration and that should
probably work. I usually change mine slightly to use compiled-in
rootfs to simplify storage setup.

In case this is helpful here's a number of commands I use to start my
test cases:

* PCIe (e1000 ethernet attached), USB (usb stick attached), SD:
arm-softmmu/qemu-system-arm -smp 2 -m 1024 -machine mcimx7d-sabre
-nographic -serial mon:stdio -kernel <path to zImage> -dtb <path to
DTB> -device e1000e,bus="dw-pcie",netdev=lan0 -netdev
tap,id=lan0,ifname=tap0,script=no,downscript=no -append
"console=ttymxc0,115200 noinitrd" -usb -drive
if=none,id=stick,file=<patch to USB stick image>,format=raw -device
usb-storage,bus=usb-bus.0,drive=stick -drive
id=sd1,if=sd,format=file,file=<path to SD1> -drive
id=sd2,if=sd,format=file,file=<path to SD2> -driv
eid=sd3,if=sd,format=file,file=<path to SD3>

* EHCI USB attached via PCIe with legacy interrupts, Ethernet
connected to built-in controller:
arm-softmmu/qemu-system-arm -smp 2 -m 1024 -machine mcimx7d-sabre
-nographic -serial mon:stdio -kernel <path to zImage> -dtb <path to
DTB> -device usb-ehci,id=ehci,bus="dw-pcie" -net
nic,model=imx.fec,netdev=lan0 -netdev
tap,id=lan0,ifname=tap0,script=no,downscript=no -append
"console=ttymxc0,115200 noinitrd pci=nomsi" -usb -drive
if=none,id=stick,file=<path to USB stick image>,format=raw

Also, I don't think anyone would try to do this, but just as a
warning, building QEMU with --enable-tcg-interpreter doesn't really
work that well (/init gets SIGKILLed every time), so I'd recommend
avoiding using that option.

Hopefully this is enough info, but if not, feel free to ask me more questions.

Thanks,
Andrey Smirnov