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 X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D19CC433E9 for ; Thu, 7 Jan 2021 02:05:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDB9D2312C for ; Thu, 7 Jan 2021 02:05:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726763AbhAGCEz (ORCPT ); Wed, 6 Jan 2021 21:04:55 -0500 Received: from mga17.intel.com ([192.55.52.151]:49782 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726681AbhAGCEz (ORCPT ); Wed, 6 Jan 2021 21:04:55 -0500 IronPort-SDR: RDo+Mx/OtYC2dFG17EqGT7QI7R1c4bWYUYTxgr0x6Jc/xke1b3spqHZIG8wmC7rBr+w39UwOzQ DOg4Si9B24Rw== X-IronPort-AV: E=McAfee;i="6000,8403,9856"; a="157144509" X-IronPort-AV: E=Sophos;i="5.79,328,1602572400"; d="scan'208";a="157144509" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jan 2021 18:03:09 -0800 IronPort-SDR: n7P5Mq/oH8n/P6xpdUTkl4TlvjA9soP50rLbD+bSq6KWCK64WUnr40vtcFN1TADUSIK2rTRo5I A3impTlyBmRQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,328,1602572400"; d="scan'208";a="462867708" Received: from allen-box.sh.intel.com (HELO [10.239.159.28]) ([10.239.159.28]) by fmsmga001.fm.intel.com with ESMTP; 06 Jan 2021 18:03:02 -0800 Cc: baolu.lu@linux.intel.com, tglx@linutronix.de, ashok.raj@intel.com, kevin.tian@intel.com, dave.jiang@intel.com, megha.dey@intel.com, dwmw2@infradead.org, alex.williamson@redhat.com, bhelgaas@google.com, dan.j.williams@intel.com, dmaengine@vger.kernel.org, eric.auger@redhat.com, jacob.jun.pan@intel.com, kvm@vger.kernel.org, kwankhede@nvidia.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, maz@kernel.org, mona.hossain@intel.com, netanelg@mellanox.com, parav@mellanox.com, pbonzini@redhat.com, rafael@kernel.org, samuel.ortiz@intel.com, sanjay.k.kumar@intel.com, shahafs@mellanox.com, tony.luck@intel.com, vkoul@kernel.org, yan.y.zhao@linux.intel.com, yi.l.liu@intel.com Subject: Re: [RFC PATCH v2 1/1] platform-msi: Add platform check for subdevice irq domain To: Leon Romanovsky , Jason Gunthorpe References: <20210106022749.2769057-1-baolu.lu@linux.intel.com> <20210106060613.GU31158@unreal> <3d2620f9-bbd4-3dd0-8e29-0cfe492a109f@linux.intel.com> <20210106104017.GV31158@unreal> <20210106152339.GA552508@nvidia.com> <20210106160158.GX31158@unreal> From: Lu Baolu Message-ID: Date: Thu, 7 Jan 2021 09:55:02 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210106160158.GX31158@unreal> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/7/21 12:01 AM, Leon Romanovsky wrote: > On Wed, Jan 06, 2021 at 11:23:39AM -0400, Jason Gunthorpe wrote: >> On Wed, Jan 06, 2021 at 12:40:17PM +0200, Leon Romanovsky wrote: >> >>> I asked what will you do when QEMU will gain needed functionality? >>> Will you remove QEMU from this list? If yes, how such "new" kernel will >>> work on old QEMU versions? >> >> The needed functionality is some VMM hypercall, so presumably new >> kernels that support calling this hypercall will be able to discover >> if the VMM hypercall exists and if so superceed this entire check. > > Let's not speculate, do we have well-known path? All these (hypercall detect and invoke) will be done in pci_subdevice_msi_create_irq_domain(). It will be transparent to the callers. > Will such patch be taken to stable@/distros? It will not be taken to stable. For distros, it depends. They can backport if they want to support the feature. Best regards, baolu