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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 D1DEBC433E0 for ; Wed, 29 Jul 2020 20:25:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF4142067D for ; Wed, 29 Jul 2020 20:25:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ca6ABU1R" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726588AbgG2UZQ (ORCPT ); Wed, 29 Jul 2020 16:25:16 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:40022 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726365AbgG2UZQ (ORCPT ); Wed, 29 Jul 2020 16:25:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596054314; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NCZpvlTRYeKn2G2IpCrrj/S3gke7jRP5RvQ+owSSG9A=; b=Ca6ABU1R9C70AarbV3y+iuoM6OUVPPR6mFvcpR/gFYww6F8dHIiEgMw6WR1qjLJdQy1nBr mBvhY7aqALB+VvJz5oospbjDjHQd+E7UVyFveVhHyZ2LhCZHKkQB6kDOivFg3clUwD5XwZ c2wNKV8vywP4t9JV9MDq/HwjAz1hGSc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-125-q_PLVkyGOsiYWaHlKxve7w-1; Wed, 29 Jul 2020 16:25:10 -0400 X-MC-Unique: q_PLVkyGOsiYWaHlKxve7w-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 09D638017FB; Wed, 29 Jul 2020 20:25:09 +0000 (UTC) Received: from x1.home (ovpn-112-71.phx2.redhat.com [10.3.112.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id 12A4B512FE; Wed, 29 Jul 2020 20:25:07 +0000 (UTC) Date: Wed, 29 Jul 2020 14:25:07 -0600 From: Alex Williamson To: Lu Baolu Cc: Joerg Roedel , Robin Murphy , Jean-Philippe Brucker , Cornelia Huck , Kevin Tian , Ashok Raj , Dave Jiang , Liu Yi L , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v3 3/4] iommu: Add iommu_aux_get_domain_for_dev() Message-ID: <20200729142507.182cd18a@x1.home> In-Reply-To: <20200714055703.5510-4-baolu.lu@linux.intel.com> References: <20200714055703.5510-1-baolu.lu@linux.intel.com> <20200714055703.5510-4-baolu.lu@linux.intel.com> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, 14 Jul 2020 13:57:02 +0800 Lu Baolu wrote: > The device driver needs an API to get its aux-domain. A typical usage > scenario is: > > unsigned long pasid; > struct iommu_domain *domain; > struct device *dev = mdev_dev(mdev); > struct device *iommu_device = vfio_mdev_get_iommu_device(dev); > > domain = iommu_aux_get_domain_for_dev(dev); > if (!domain) > return -ENODEV; > > pasid = iommu_aux_get_pasid(domain, iommu_device); > if (pasid <= 0) > return -EINVAL; > > /* Program the device context */ > .... > > This adds an API for such use case. > > Suggested-by: Alex Williamson > Signed-off-by: Lu Baolu > --- > drivers/iommu/iommu.c | 18 ++++++++++++++++++ > include/linux/iommu.h | 7 +++++++ > 2 files changed, 25 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index cad5a19ebf22..434bf42b6b9b 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -2817,6 +2817,24 @@ void iommu_aux_detach_group(struct iommu_domain *domain, > } > EXPORT_SYMBOL_GPL(iommu_aux_detach_group); > > +struct iommu_domain *iommu_aux_get_domain_for_dev(struct device *dev) > +{ > + struct iommu_domain *domain = NULL; > + struct iommu_group *group; > + > + group = iommu_group_get(dev); > + if (!group) > + return NULL; > + > + if (group->aux_domain_attached) > + domain = group->domain; Why wouldn't the aux domain flag be on the domain itself rather than the group? Then if we wanted sanity checking in patch 1/ we'd only need to test the flag on the object we're provided. If we had such a flag, we could create an iommu_domain_is_aux() function and then simply use iommu_get_domain_for_dev() and test that it's an aux domain in the example use case. It seems like that would resolve the jump from a domain to an aux-domain just as well as adding this separate iommu_aux_get_domain_for_dev() interface. The is_aux test might also be useful in other cases too. Thanks, Alex > + > + iommu_group_put(group); > + > + return domain; > +} > +EXPORT_SYMBOL_GPL(iommu_aux_get_domain_for_dev); > + > /** > * iommu_sva_bind_device() - Bind a process address space to a device > * @dev: the device > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 9506551139ab..cda6cef7579e 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -639,6 +639,7 @@ int iommu_aux_attach_group(struct iommu_domain *domain, > struct iommu_group *group, struct device *dev); > void iommu_aux_detach_group(struct iommu_domain *domain, > struct iommu_group *group, struct device *dev); > +struct iommu_domain *iommu_aux_get_domain_for_dev(struct device *dev); > > struct iommu_sva *iommu_sva_bind_device(struct device *dev, > struct mm_struct *mm, > @@ -1040,6 +1041,12 @@ iommu_aux_detach_group(struct iommu_domain *domain, > { > } > > +static inline struct iommu_domain * > +iommu_aux_get_domain_for_dev(struct device *dev) > +{ > + return NULL; > +} > + > static inline struct iommu_sva * > iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata) > {