From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8025F35293A; Wed, 12 Nov 2025 18:25:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762971929; cv=none; b=Mw1HxeREJGFC/dbt2WiNkn/LQrMFzE/tWs+EJRD4SLB+R5OjIqtpA3PeqhgC8d8ZCyfWovdzN+bYw3dkIrJI9B9LBrVlcKQpfCpq9xvgoQBi4YwwmmNh0dChj7wLCioJ4IIUvtHfIPA58G2WaUfVZvzV1cs17k0/6EM/vuxAh3M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762971929; c=relaxed/simple; bh=lizdUnDeduoQiKv5+ThT5MsgZaSyS7YSf7d07ugaIXY=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=OBjiCLxwniSQuyevLc7AIyJZJSH5tjLo0K2wgNZX7IJRw17T+pgjSAd24C1eQCE47GfwOcyvOYkpvIg/DR2ZS8WOrsFJdqR4C8okBo8gJzABeQSoyPLqDKifqgccLG3uncsS6WmANIiZ6gDW4InZox5KW8JOCag1bj634bcv4iA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4d6BdZ5JZczJ46DR; Thu, 13 Nov 2025 02:24:50 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id 9C3491402F1; Thu, 13 Nov 2025 02:25:23 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Wed, 12 Nov 2025 18:25:22 +0000 Date: Wed, 12 Nov 2025 18:25:21 +0000 From: Jonathan Cameron To: Marc Zyngier CC: , , , Thomas Gleixner , "Mark Rutland" , Will Deacon , "Rafael J. Wysocki" , Rob Herring , "Saravana Kannan" , Greg Kroah-Hartman , Sven Peter , Janne Grunau , Suzuki K Poulose , James Clark , Jinjie Ruan , "Alexandru Elisei" Subject: Re: [PATCH v4 16/26] genirq: Allow per-cpu interrupt sharing for non-overlapping affinities Message-ID: <20251112182521.000027ad@huawei.com> In-Reply-To: <20251020122944.3074811-17-maz@kernel.org> References: <20251020122944.3074811-1-maz@kernel.org> <20251020122944.3074811-17-maz@kernel.org> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500011.china.huawei.com (7.191.174.215) To dubpeml100005.china.huawei.com (7.214.146.113) On Mon, 20 Oct 2025 13:29:33 +0100 Marc Zyngier wrote: > Interrupt sharing for percpu-devid interrupts is forbidden, and > for good reasons. These are interrupts generated *from* a CPU and > handled by itself (timer, for example). Nobody in their right mind > would put two devices on the same pin (and if they have, they get to > keep the pieces...). > > But this also prevents more benign cases, where devices are connected > to groups of CPUs, and for which the affinities are not overlapping. > Effectively, the only thing they share is the interrupt number, and > nothing else. > > Let's tweak the definition of IRQF_SHARED applied to percpu_devid > interrupts to allow this particular case. This results in extra > validation at the point of the interrupt being setup and freed, > as well as a tiny bit of extra complexity for interrupts at handling > time (to pick the correct irqaction). > > Tested-by: Will Deacon > Signed-off-by: Marc Zyngier Reviewed-by: Jonathan Cameron