Re: [PATCH v2] Revert "target/mips: Deprecate nanoMIPS ISA" - Philippe Mathieu-Daudé

From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: Vince Del Vecchio <Vince.DelVecchio@mediatek.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	Aleksandar Rikalo <Aleksandar.Rikalo@syrmia.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: "paulburton@kernel.org" <paulburton@kernel.org>,
	Stefan Weil <sw@weilnetz.de>,
	"chenhuacai@kernel.org" <chenhuacai@kernel.org>,
	Petar Jovanovic <petar.jovanovic@syrmia.com>,
	"aurelien@aurel32.net" <aurelien@aurel32.net>,
	Filip Vidojevic <Filip.Vidojevic@Syrmia.com>
Subject: Re: [PATCH v2] Revert "target/mips: Deprecate nanoMIPS ISA"
Date: Mon, 19 Apr 2021 20:11:06 +0200	[thread overview]
Message-ID: <7c630c72-580f-ab67-be62-aaf01768c5a6@amsat.org> (raw)
In-Reply-To: <b858a20e97b74e7b90a94948314d0008@MTKMBS62N2.mediatek.inc>

Hi Vince,

On 4/9/21 3:10 AM, Vince Del Vecchio wrote:
> On Tuesday, April 6, 2021 11:21 AM, Richard Henderson wrote:
> 
>> I think we should retain the deprecation until you actually follow through with any of the upstreaming.

> In sum, we're investing in open source nanoMIPS tools because it's an important technology for us, and QEMU is one of the key projects we want to have nanoMIPS supported in.

I'm glad MediaTek has interest in MIPS and is willing to contribute
upstream and help in maintenance! QEMU MIPS codebase is huge and I
don't have the time/resources to maintain it alone.

Regarding the nanoMIPS deprecation, don't worry, we are not going to
remove the nanoMIPS TCG and I7200 core because 1/ it is not breaking
anything, 2/ it is in good shape and 3/ most importantly there are
users in the community.

The plan is to drop the nanoMIPS disassembler because it is broken
since more than 2 years and nobody ever cared to fix it after Stefan's
attempt in Nov 2018:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg576504.html
So it is certainly unused. Unused unmaintained code has a cost and
negative impact to the generic project development.

If you think it is worth having, you should consider moving it to
the capstone project (https://www.capstone-engine.org/ - it also
uses C++ btw), so other projects could disassemble nanoMIPS blobs.

I prepared a series [1] which split the TCG code from the big
translate.c in one file per ISA. It helps maintenance, as we can
have finer granularity in who reviews/maintains what (using
MAINTAINERS sections) easing collective maintenance in a community.
I'll Cc your team for help with reviewing it when I repost it
(give me up to 1 month).

Regards,

Phil.

[1] https://lists.gnu.org/archive/html/qemu-devel/2020-11/msg05879.html