[06/13] selftests/nolibc: allow specify a bios for qemu

  riscv qemu has a builtin bios (opensbi), but it may not match the latest
kernel and some old versions may hang during boot, let's allow user pass
a newer version to qemu via the -bios option.

we can use it like this:

    $ make run BIOS=/path/to/new-bios ...

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/testing/selftests/nolibc/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
  

On 2023-05-25 01:52:29+0800, Zhangjin Wu wrote:
> riscv qemu has a builtin bios (opensbi), but it may not match the latest
> kernel and some old versions may hang during boot, let's allow user pass
> a newer version to qemu via the -bios option.

Nitpick:

This seems very specific and hopefully only necessary temporarily.

Instead it could be changed to some generic mechanim like
"QEMU_ARGS_EXTRA"?

> we can use it like this:
> 
>     $ make run BIOS=/path/to/new-bios ...
> 
> Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
> ---
>  tools/testing/selftests/nolibc/Makefile | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
> index 9adc8944dd80..9213763ab3b6 100644
> --- a/tools/testing/selftests/nolibc/Makefile
> +++ b/tools/testing/selftests/nolibc/Makefile
> @@ -70,7 +70,8 @@ QEMU_ARGS_mips       = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
>  QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
>  QEMU_ARGS_s390       = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
>  QEMU_ARGS_loongarch  = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
> -QEMU_ARGS            = $(QEMU_ARGS_$(ARCH))
> +QEMU_ARGS_BIOS       = $(if $(BIOS),-bios $(BIOS))
> +QEMU_ARGS            = $(QEMU_ARGS_$(ARCH)) $(QEMU_ARGS_BIOS)
>  
>  # OUTPUT is only set when run from the main makefile, otherwise
>  # it defaults to this nolibc directory.
> -- 
> 2.25.1
>
  

Hi, Thomas

> On 2023-05-25 01:52:29+0800, Zhangjin Wu wrote:
> > riscv qemu has a builtin bios (opensbi), but it may not match the latest
> > kernel and some old versions may hang during boot, let's allow user pass
> > a newer version to qemu via the -bios option.
> 
> Nitpick:
> 
> This seems very specific and hopefully only necessary temporarily.
>

RISC-V is such a new ISA and the Spec (especially the SBI) changes very
frequently ;-)

> Instead it could be changed to some generic mechanim like
> "QEMU_ARGS_EXTRA"?
>

Good point, will apply it.

Thanks,
Zhangjin

> > we can use it like this:
> > 
> >     $ make run BIOS=/path/to/new-bios ...
> > 
> > Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
> > ---
> >  tools/testing/selftests/nolibc/Makefile | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
> > index 9adc8944dd80..9213763ab3b6 100644
> > --- a/tools/testing/selftests/nolibc/Makefile
> > +++ b/tools/testing/selftests/nolibc/Makefile
> > @@ -70,7 +70,8 @@ QEMU_ARGS_mips       = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
> >  QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
> >  QEMU_ARGS_s390       = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
> >  QEMU_ARGS_loongarch  = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
> > -QEMU_ARGS            = $(QEMU_ARGS_$(ARCH))
> > +QEMU_ARGS_BIOS       = $(if $(BIOS),-bios $(BIOS))
> > +QEMU_ARGS            = $(QEMU_ARGS_$(ARCH)) $(QEMU_ARGS_BIOS)
> >  
> >  # OUTPUT is only set when run from the main makefile, otherwise
> >  # it defaults to this nolibc directory.
  

On Fri, May 26, 2023 at 06:25:18PM +0800, Zhangjin Wu wrote:

> > On 2023-05-25 01:52:29+0800, Zhangjin Wu wrote:
> > > riscv qemu has a builtin bios (opensbi), but it may not match the latest
> > > kernel and some old versions may hang during boot, let's allow user pass
> > > a newer version to qemu via the -bios option.
> > 
> > Nitpick:
> > 
> > This seems very specific and hopefully only necessary temporarily.
> >
> 
> RISC-V is such a new ISA and the Spec (especially the SBI) changes very
> frequently ;-)


Huh. Could you please expand on which versions of QEMU will hang while
booting an upstream or stable kernel? Which kernels would be good to
know too.

Thanks,
Conor.
  

Hi, Conor.

> 
> On Fri, May 26, 2023 at 06:25:18PM +0800, Zhangjin Wu wrote:
> 
> > > On 2023-05-25 01:52:29+0800, Zhangjin Wu wrote:
> > > > riscv qemu has a builtin bios (opensbi), but it may not match the latest
> > > > kernel and some old versions may hang during boot, let's allow user pass
> > > > a newer version to qemu via the -bios option.
> > >
> > > Nitpick:
> > >
> > > This seems very specific and hopefully only necessary temporarily.
> > >
> >
> > RISC-V is such a new ISA and the Spec (especially the SBI) changes very
> > frequently ;-)
> 
> Huh. Could you please expand on which versions of QEMU will hang while
> booting an upstream or stable kernel? Which kernels would be good to
> know too.
> 

As the cover letter listed (in the Environment section), the softwares we
used are:

    // higher qemu version is better, latest version is v8.0.0+
    $ qemu-system-riscv64  --version
    QEMU emulator version 4.2.1 (Debian 1:4.2-3ubuntu6.18)
    Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers

    // opensbi version, higher is better, must match kernel version and qemu version
    // rv64: used version is 1.2, latest is 1.2
    $ head -2 /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/run.out | tail -1
    OpenSBI v1.2-116-g7919530
    // rv32: used version is v0.9, latest is 1.2
    $ head -2 /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/run.out | tail -1
    OpenSBI v0.9-152-g754d511

The kernel version is the one this patchset based on (Willy's nolibc
repo), it is v6.4-rc1.

qemu v4.2.1 is the one systematically installed (/usr/bin) from the
qemu-system-misc package and used to test this patchset in my Ubuntu
20.04 based test docker image.

Just installed a v7.0.0 qemu from ppa:canonical-server/server-backports,
there is no default opensbi, and re-checked, there is one prebuilt
opensbi for rv64, but still no prebuilt opensbi for rv32.

    $ sudo add-apt-repository ppa:canonical-server/server-backports
    $ sudo apt install qemu-system-misc

    $ sudo apt install opensbi
    $ dpkg -S opensbi | grep -E "fw_*bin|elf"
    qemu-system-data: /usr/share/qemu/opensbi-riscv64-generic-fw_dynamic.elf
    opensbi: /usr/lib/riscv64-linux-gnu/opensbi/generic/fw_dynamic.elf
    opensbi: /usr/lib/riscv64-linux-gnu/opensbi/generic/fw_jump.elf

    $ qemu-system-riscv32 -display none -no-reboot -kernel build/riscv32/virt/linux/v6.4-rc1/arch/riscv/boot/Image -serial stdio -M virt -append "console=ttyS0 panic=-1"
    qemu-system-riscv32: Unable to load the RISC-V firmware "opensbi-riscv32-generic-fw_dynamic.bin"

I used the one built myself, If not want to build such opensbi manually,
we can download one (1.2 currently) from qemu source code:

    https://gitlab.com/qemu-project/qemu/-/blob/master/pc-bios/opensbi-riscv32-generic-fw_dynamic.bin

Then, we can use it like this:

    $ qemu-system-riscv32 -display none -no-reboot -kernel build/riscv32/virt/linux/v6.4-rc1/arch/riscv/boot/Image -serial stdio -M virt -append "console=ttyS0 panic=-1" -bios /path/to/opensbi-riscv32-generic-fw_dynamic.bin

Will append this extra info in the commit message of the coming new
revision of this patch, thanks a lot.

The hang issue I mentioned may be using one of my older prebuilt version of
opensbi, I can not find which one it exactly is, so, please ignore that info,
will update that description too.

Btw, something not about this patch: qemu v8.0.0 seems not boot non-mmu
v6.3, both sides have issues, not dig into it carefully, so, not report
it yet.

Thanks,
Zhangjin

> Thanks,
> Conor.
  

On Fri, May 26, 2023 at 09:38:25PM +0800, Zhangjin Wu wrote:
> Hi, Conor.
> 
> > 
> > On Fri, May 26, 2023 at 06:25:18PM +0800, Zhangjin Wu wrote:
> > 
> > > > On 2023-05-25 01:52:29+0800, Zhangjin Wu wrote:
> > > > > riscv qemu has a builtin bios (opensbi), but it may not match the latest
> > > > > kernel and some old versions may hang during boot, let's allow user pass
> > > > > a newer version to qemu via the -bios option.
> > > >
> > > > Nitpick:
> > > >
> > > > This seems very specific and hopefully only necessary temporarily.
> > > >
> > >
> > > RISC-V is such a new ISA and the Spec (especially the SBI) changes very
> > > frequently ;-)
> > 
> > Huh. Could you please expand on which versions of QEMU will hang while
> > booting an upstream or stable kernel? Which kernels would be good to
> > know too.
> > 
> 
> As the cover letter listed (in the Environment section), the softwares we
> used are:

Not super interested in those ones since they work ;)

> The kernel version is the one this patchset based on (Willy's nolibc
> repo), it is v6.4-rc1.
> 
> qemu v4.2.1 is the one systematically installed (/usr/bin) from the
> qemu-system-misc package and used to test this patchset in my Ubuntu
> 20.04 based test docker image.

Okay, in the context of RISC-V, that is pretty ancient ;)

> Just installed a v7.0.0 qemu from ppa:canonical-server/server-backports,
> there is no default opensbi, and re-checked, there is one prebuilt
> opensbi for rv64, but still no prebuilt opensbi for rv32.

Ah, I see.

> The hang issue I mentioned may be using one of my older prebuilt version of
> opensbi, I can not find which one it exactly is, so, please ignore that info,
> will update that description too.

Okay. If you do manage to reproduce it, LMK! I was/am just worried we
have some regressions because you should be able to keep booting with
those older opensbi versions, modulo some Kconfig changes - although if
it is something like qemu 4.2.1 specific I don't think I care all that
much about dinosaurs ;)

> Btw, something not about this patch: qemu v8.0.0 seems not boot non-mmu
> v6.3, both sides have issues, not dig into it carefully, so, not report
> it yet.

Cool. Feel free to CC me on whatever you discover. nommu gets little
enough testing in mainline, and even less in stable kernels. That reminds
me, I do need to add 32-bit nommu to the patchwork automation for
linux-riscv.

Thanks,
Conor.
  

On Fri, May 26, 2023 at 09:00:02AM +0200, Thomas Weißschuh wrote:
> On 2023-05-25 01:52:29+0800, Zhangjin Wu wrote:
> > riscv qemu has a builtin bios (opensbi), but it may not match the latest
> > kernel and some old versions may hang during boot, let's allow user pass
> > a newer version to qemu via the -bios option.
> 
> Nitpick:
> 
> This seems very specific and hopefully only necessary temporarily.
> 
> Instead it could be changed to some generic mechanim like
> "QEMU_ARGS_EXTRA"?

FWIW I, too, think that QEMU_ARGS_EXTRA could be very convenient for
various test cases on any architecture (change number of CPUs, RAM
size, boot options etc).

Willy