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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 EA037C2D0A3 for ; Mon, 16 Nov 2020 17:58:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EB38222E8 for ; Mon, 16 Nov 2020 17:58:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="nBGp3JNg"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="xxLH7da1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387829AbgKPR4f (ORCPT ); Mon, 16 Nov 2020 12:56:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387513AbgKPR4e (ORCPT ); Mon, 16 Nov 2020 12:56:34 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC33AC0613CF; Mon, 16 Nov 2020 09:56:34 -0800 (PST) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1605549393; 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=/4Dj4H4h07T3HAdVoU3L0DmQaoeq12MkqX6wjjZOegA=; b=nBGp3JNgdM2ohDkTTKJk3iDoHDePjcC35N1cE/kHdVkfINkXyyDrvHUtP/WpveXZe5BFgW C5NsffljQAIk3bx4ZPB/QKt2B4n1PKGZKDwVLMr80B07vhBNNrdSvcTDRLVhip02c2EykS C0yJ+BbYBfpc97IFvpks8xyZ1Pl+VSIwJvHj3MlZ7I0177vAtCom12kyEH/h0JvOHu7a+F SpOl07nr6kv/+P47LGoE9cSZehjaOGqrtUYgzL7D9GJIZxO2ZPtalnUvv72o09gWFKqLXZ yrFK5EgLGLYWCWQGi27BLzkhXCdD/dU3CUM4lu/7psDSHvE6jPhvBylg5/a1yQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1605549393; 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=/4Dj4H4h07T3HAdVoU3L0DmQaoeq12MkqX6wjjZOegA=; b=xxLH7da1/bbkHaKVfEDfUOMlDxTKQrHyxLLt/pKG4NijVWYaDvU4EIFGsiDWcmWfVFWpqV OMKDOAshoXel6PDg== To: Jason Gunthorpe , "Tian\, Kevin" Cc: "Raj\, Ashok" , Christoph Hellwig , "Wilk\, Konrad" , "Williams\, Dan J" , "Jiang\, Dave" , Bjorn Helgaas , "vkoul\@kernel.org" , "Dey\, Megha" , "maz\@kernel.org" , "bhelgaas\@google.com" , "alex.williamson\@redhat.com" , "Pan\, Jacob jun" , "Liu\, Yi L" , "Lu\, Baolu" , "Kumar\, Sanjay K" , "Luck\, Tony" , "kwankhede\@nvidia.com" , "eric.auger\@redhat.com" , "parav\@mellanox.com" , "rafael\@kernel.org" , "netanelg\@mellanox.com" , "shahafs\@mellanox.com" , "yan.y.zhao\@linux.intel.com" , "pbonzini\@redhat.com" , "Ortiz\, Samuel" , "Hossain\, Mona" , "dmaengine\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" , "linux-pci\@vger.kernel.org" , "kvm\@vger.kernel.org" Subject: Re: [PATCH v4 06/17] PCI: add SIOV and IMS capability detection In-Reply-To: <20201116154635.GK917484@nvidia.com> References: <20201112193253.GG19638@char.us.oracle.com> <877dqqmc2h.fsf@nanos.tec.linutronix.de> <20201114103430.GA9810@infradead.org> <20201114211837.GB12197@araj-mobl1.jf.intel.com> <877dqmamjl.fsf@nanos.tec.linutronix.de> <20201115193156.GB14750@araj-mobl1.jf.intel.com> <875z665kz4.fsf@nanos.tec.linutronix.de> <20201116002232.GA2440@araj-mobl1.jf.intel.com> <20201116154635.GK917484@nvidia.com> Date: Mon, 16 Nov 2020 18:56:33 +0100 Message-ID: <87y2j1xk1a.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 16 2020 at 11:46, Jason Gunthorpe wrote: > On Mon, Nov 16, 2020 at 07:31:49AM +0000, Tian, Kevin wrote: > >> > The subdevices require PASID & IOMMU in native, but inside the guest there >> > is no >> > need for IOMMU unless you want to build SVM on top. subdevices work >> > without >> > any vIOMMU or hypercall in the guest. Only because they look like normal >> > PCI devices we could map interrupts to legacy MSIx. >> >> Guest managed subdevices on PF/VF requires vIOMMU. > > Why? I've never heard we need vIOMMU for our existing SRIOV flows in > VMs?? Handing PF/VF into the guest does not require it. But if the PF/VF driver in the guest wants to create and manage the magic mdev subdevices which require PASID support then you surely need it. Thanks, tglx