linux-kernel - Re: [PATCH v3 15/21] x86/xen: Drop xen_irq

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Message-ID: <20251006185553.GY3245006@noisy.programming.kicks-ass.net>
Date: Mon, 6 Oct 2025 20:55:53 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Juergen Gross <jgross@...e.com>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	xen-devel@...ts.xenproject.org
Subject: Re: [PATCH v3 15/21] x86/xen: Drop xen_irq_ops

On Mon, Oct 06, 2025 at 09:46:00AM +0200, Juergen Gross wrote:
> Instead of having a pre-filled array xen_irq_ops for Xen PV paravirt
> functions, drop the array and assign each element individually.

Same comment for the next few patches; this changelog is a little light
on *why*. I mean, I don't mind the change, but supposedly we should
justify things at least a little, right? :-)

> Signed-off-by: Juergen Gross <jgross@...e.com>
> ---
> V2:
> - new patch
> ---
>  arch/x86/xen/irq.c    | 20 +++++++-------------
>  tools/objtool/check.c |  1 -
>  2 files changed, 7 insertions(+), 14 deletions(-)
> 
> diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
> index 39982f955cfe..d8678c3d3971 100644
> --- a/arch/x86/xen/irq.c
> +++ b/arch/x86/xen/irq.c
> @@ -40,20 +40,14 @@ static void xen_halt(void)
>  		xen_safe_halt();
>  }
>  
> -static const typeof(pv_ops) xen_irq_ops __initconst = {
> -	.irq = {
> -		/* Initial interrupt flag handling only called while interrupts off. */
> -		.save_fl = __PV_IS_CALLEE_SAVE(paravirt_ret0),
> -		.irq_disable = __PV_IS_CALLEE_SAVE(paravirt_nop),
> -		.irq_enable = __PV_IS_CALLEE_SAVE(BUG_func),
> -
> -		.safe_halt = xen_safe_halt,
> -		.halt = xen_halt,
> -	},
> -};
> -
>  void __init xen_init_irq_ops(void)
>  {
> -	pv_ops.irq = xen_irq_ops.irq;
> +	/* Initial interrupt flag handling only called while interrupts off. */
> +	pv_ops.irq.save_fl = __PV_IS_CALLEE_SAVE(paravirt_ret0);
> +	pv_ops.irq.irq_disable = __PV_IS_CALLEE_SAVE(paravirt_nop);
> +	pv_ops.irq.irq_enable = __PV_IS_CALLEE_SAVE(BUG_func);
> +	pv_ops.irq.safe_halt = xen_safe_halt;
> +	pv_ops.irq.halt = xen_halt;
> +
>  	x86_init.irqs.intr_init = xen_init_IRQ;
>  }
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index a72059fcbc83..d66eb37ff294 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -593,7 +593,6 @@ static int init_pv_ops(struct objtool_file *file)
>  	static const char *pv_ops_tables[] = {
>  		"pv_ops",
>  		"xen_cpu_ops",
> -		"xen_irq_ops",
>  		"xen_mmu_ops",
>  		NULL,
>  	};
> -- 
> 2.51.0
>