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

From: Conor Dooley <conor@kernel.org>
To: Zhangjin Wu <falcon@tinylab.org>
Cc: conor.dooley@microchip.com, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-riscv@lists.infradead.org,
	palmer@dabbelt.com, paul.walmsley@sifive.com, thomas@t-8ch.de,
	w@1wt.eu
Subject: Re: [PATCH 06/13] selftests/nolibc: allow specify a bios for qemu
Date: Fri, 26 May 2023 16:08:32 +0100	[thread overview]
Message-ID: <20230526-humongous-manifesto-3c44973f0df1@spud> (raw)
In-Reply-To: <20230526133825.198100-1-falcon@tinylab.org>

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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.

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