linux-kernel - Re: [PATCH v16 05/30] LoongArch: KVM: Add vcpu related header files

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Message-ID: <6a5ed2266138cc61cbe27577424bb53cda72378d.camel@xry111.site>
Date:   Fri, 14 Jul 2023 20:06:20 +0800
From:   Xi Ruoyao <xry111@...111.site>
To:     WANG Xuerui <kernel@...0n.name>, bibo mao <maobibo@...ngson.cn>,
        Huacai Chen <chenhuacai@...nel.org>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        loongarch@...ts.linux.dev, Jens Axboe <axboe@...nel.dk>,
        Mark Brown <broonie@...nel.org>,
        Oliver Upton <oliver.upton@...ux.dev>, hejinyang@...ngson.cn,
        Tianrui Zhao <zhaotianrui@...ngson.cn>
Subject: Re: [PATCH v16 05/30] LoongArch: KVM: Add vcpu related header files

On Fri, 2023-07-14 at 18:16 +0800, WANG Xuerui wrote:
> > > > > As all needed instructions have already upstream in binutils now and
> > > > > binutils 2.41 will be released soon, I suggest again to introduce
> > > > > AS_HAS_LVZ_EXTENSION and make KVM depend on AS_HAS_LVZ_EXTENSION.
> > > > It is a good news that binutils 2.41 has supported LVZ assemble language.
> > > > we will add AS_HAS_LVZ_EXTENSION support, however KVM need not depend on
> > > > AS_HAS_LVZ_EXTENSION since bintuils 2.41 is not popularly used. yeap we
> > > > need write beautiful code, also we should write code with pratical usage.

I've raised this for a very early version of this series, but Paolo
decided using .word here should be fine:

https://lore.kernel.org/all/87268dce-1b5d-0556-7e65-2a75a7893cd1@redhat.com/

So in this case we should respect the decision of the KVM reviewer.  If
this breaks Clang build, we should improve Clang to support using .word
for hard coding an opcode.

Frankly I'm quite frustrated by "a new architecture needs so many
feature tests and hacks, here and there" and sometimes I just want to go
laid-up in bed instead of writing code or porting the distro (Linux From
Scratch).  But today I just got [a board from another Chinese vendor
targeting another new architecture] and to me they are doing things even
worse...  So maybe we are facing some inherent "no silver bullet
engineering issue".

-- 
Xi Ruoyao <xry111@...111.site>
School of Aerospace Science and Technology, Xidian University