From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6F44C433F5 for ; Fri, 6 May 2022 20:05:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1391291AbiEFUJY (ORCPT ); Fri, 6 May 2022 16:09:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352661AbiEFUJW (ORCPT ); Fri, 6 May 2022 16:09:22 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D24913E9D for ; Fri, 6 May 2022 13:05:36 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1651867535; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=MVppxWloPHGJWVXPfoL2Mp1gCDmCbq5jYvkOUctTPwE=; b=zS7mT4GOFbktfGjTiNzsOezexuL61fgcFzjZlZAaPH7GPyJ2Q7bJAFEDsyscoPuCfFVQXy MQv9fxTolSCsKtYLSyZInAmifCbsge2rcmwRurq4fs6letvqkFnJbaTyhjCsRTPV60X6uE rinuSxovZT2eQZmTTINCqVtTXoHEFIdOgI1zfPR/KL1VUfVwn2fIFHM766ozhigodnfH5s jReDujbvbA2//EkDSTXQNLuOihMxNNQNvdzlCmWip8r6V8GGcekFaYq43MM8Slzjs9F8uF PGtWQGOFlmpNWcrTP2AzpuqH8ZoMSNTnNEko3cwpIKeOk6ve9AbhRkGjDS/MIg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1651867535; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=MVppxWloPHGJWVXPfoL2Mp1gCDmCbq5jYvkOUctTPwE=; b=5wkuYkNHIkwqACUXoQDb2h1xfBOD4wVbdnhxKNW06YuXNMEFHsj/QnO9X2mOg3FHRYYiy1 G0NPRPNdhl+hS1AA== To: Ricardo Neri , x86@kernel.org Cc: Tony Luck , Andi Kleen , Stephane Eranian , Andrew Morton , Joerg Roedel , Suravee Suthikulpanit , David Woodhouse , Lu Baolu , Nicholas Piggin , "Ravi V. Shankar" , Ricardo Neri , iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Ricardo Neri Subject: Re: [PATCH v6 03/29] x86/apic/msi: Set the delivery mode individually for each IRQ In-Reply-To: <20220506000008.30892-4-ricardo.neri-calderon@linux.intel.com> References: <20220506000008.30892-1-ricardo.neri-calderon@linux.intel.com> <20220506000008.30892-4-ricardo.neri-calderon@linux.intel.com> Date: Fri, 06 May 2022 22:05:34 +0200 Message-ID: <8735hmh1f5.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 05 2022 at 16:59, Ricardo Neri wrote: > There are no restrictions in hardware to set MSI messages with its > own delivery mode. "messages with its own" ? Plural/singular confusion. > Use the mode specified in the provided IRQ hardware > configuration data. Since most of the IRQs are configured to use the > delivery mode of the APIC driver in use (set in all of them to > APIC_DELIVERY_MODE_FIXED), the only functional changes are where > IRQs are configured to use a specific delivery mode. This does not parse. There are no functional changes due to this patch and there is no point talking about functional changes in subsequent patches here. > Changing the utility function __irq_msi_compose_msg() takes care of > implementing the change in the in the local APIC, PCI-MSI, and DMAR-MSI in the in the > irq_chips. > > The IO-APIC irq_chip configures the entries in the interrupt redirection > table using the delivery mode specified in the corresponding MSI message. > Since the MSI message is composed by a higher irq_chip in the hierarchy, > it does not need to be updated. The point is that updating __irq_msi_compose_msg() covers _all_ MSI consumers including IO-APIC. I had to read that changelog 3 times to make sense of it. Something like this perhaps: "x86/apic/msi: Use the delivery mode from irq_cfg for message composition irq_cfg provides a delivery mode for each interrupt. Use it instead of the hardcoded APIC_DELIVERY_MODE_FIXED. This allows to compose messages for NMI delivery mode which is required to implement a HPET based NMI watchdog. No functional change as the default delivery mode is set to APIC_DELIVERY_MODE_FIXED." Thanks, tglx