linux-kernel - Re: [RFC][PATCH 18/22] x86,kvm: Remove .fixup usage

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Date:   Fri, 5 Nov 2021 08:58:51 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org, jpoimboe@...hat.com,
        mark.rutland@....com, dvyukov@...gle.com, seanjc@...gle.com,
        mbenes@...e.cz
Subject: Re: [RFC][PATCH 18/22] x86,kvm: Remove .fixup usage

On Thu, Nov 04, 2021 at 07:50:36PM +0100, Paolo Bonzini wrote:

> > +	FOP1E(op, dst) _ASM_EXTABLE_TYPE(10b, 10b, EX_TYPE_KVM_FASTOP)
> 
> There's a ret right after the 10b label, so I think you can just use this:
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 493511efa3dc..f382c03c5954 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -315,7 +315,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
>  	__FOP_FUNC(#name)
>  #define __FOP_RET(name) \
> -	"ret \n\t" \
> +	"11: ret \n\t" \
>  	".size " name ", .-" name "\n\t"
>  #define FOP_RET(name) \
> @@ -344,7 +344,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
>  	__FOP_RET(#op "_" #dst)
>  #define FOP1EEX(op,  dst) \
> -	FOP1E(op, dst) _ASM_EXTABLE(10b, kvm_fastop_exception)
> +	FOP1E(op, dst) _ASM_EXTABLE_TYPE_REG(10b, 11b, EX_TYPE_ZERO_REG, %esi)
>  #define FASTOP1(op) \
>  	FOP_START(op) \

That's much nicer, thanks!