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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 BF1CCC433E9 for ; Thu, 14 Jan 2021 13:27:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 999BD23A58 for ; Thu, 14 Jan 2021 13:27:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727414AbhANN1L (ORCPT ); Thu, 14 Jan 2021 08:27:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:39076 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725878AbhANN1L (ORCPT ); Thu, 14 Jan 2021 08:27:11 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3668623A58; Thu, 14 Jan 2021 13:26:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610630790; bh=pUHiAeG5B7eg+14rQEcLNRaPP+p/BvCBAhX+WbpqzEo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kL+7l6nV0RlFWn8vNRaoNotAHdkSEZNQTh1EFxa2ZZLqXOiOAX4Ji0NuL/7eL3sI1 RrUcIt8olVZjn10misz9gXVu9x+wjWzv1XEs1+3xrIOFhUnMv6NOHcd4woFkej9cHi wi7c9P64wViO1q4AOuubR3XOUDvSP9Ck9vUbnyUm9o59jNS53aGBCttL/Ck2S2/LoC QCxgyFkZ4A1/xCrfN6uuejigAsjuTgY0hBtCzXaBTtKbgUE8Mfy1EP5+5G2TsdAqGl QQ9b3PJpBkzBDi+VyLBuULL4JiTiDtfC2GoHXkqt77ZrhzNIXbKJ+RYlfsJMq1H1nZ JdWjA4IjRRnjw== Date: Thu, 14 Jan 2021 15:26:27 +0200 From: Leon Romanovsky To: Lu Baolu Cc: 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, will@kernel.org, joro@8bytes.org, dmaengine@vger.kernel.org, eric.auger@redhat.com, jacob.jun.pan@intel.com, jgg@mellanox.com, kvm@vger.kernel.org, kwankhede@nvidia.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, iommu@lists.linux-foundation.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 v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU Message-ID: <20210114132627.GA944463@unreal> References: <20210114013003.297050-1-baolu.lu@linux.intel.com> <20210114013003.297050-2-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210114013003.297050-2-baolu.lu@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote: > Some vendor IOMMU drivers are able to declare that it is running in a VM > context. This is very valuable for the features that only want to be > supported on bare metal. Add a capability bit so that it could be used. And how is it used? Who and how will set it? > > Signed-off-by: Lu Baolu > --- > drivers/iommu/intel/iommu.c | 20 ++++++++++++++++++++ > drivers/iommu/virtio-iommu.c | 9 +++++++++ > include/linux/iommu.h | 1 + > 3 files changed, 30 insertions(+) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index cb205a04fe4c..8eb022d0e8aa 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -5738,12 +5738,32 @@ static inline bool nested_mode_support(void) > return ret; > } > > +static inline bool caching_mode_enabled(void) > +{ Kernel coding style is not in favour of inline functions in *.c files. > + struct dmar_drhd_unit *drhd; > + struct intel_iommu *iommu; > + bool ret = false; > + > + rcu_read_lock(); > + for_each_active_iommu(iommu, drhd) { > + if (cap_caching_mode(iommu->cap)) { > + ret = true; > + break; > + } > + } > + rcu_read_unlock(); > + > + return ret; > +} > + > static bool intel_iommu_capable(enum iommu_cap cap) > { > if (cap == IOMMU_CAP_CACHE_COHERENCY) > return domain_update_iommu_snooping(NULL) == 1; > if (cap == IOMMU_CAP_INTR_REMAP) > return irq_remapping_enabled == 1; > + if (cap == IOMMU_CAP_VIOMMU) > + return caching_mode_enabled(); > > return false; > } > diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c > index 2bfdd5734844..719793e103db 100644 > --- a/drivers/iommu/virtio-iommu.c > +++ b/drivers/iommu/virtio-iommu.c > @@ -931,7 +931,16 @@ static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args) > return iommu_fwspec_add_ids(dev, args->args, 1); > } > > +static bool viommu_capable(enum iommu_cap cap) > +{ > + if (cap == IOMMU_CAP_VIOMMU) > + return true; > + > + return false; > +} > + > static struct iommu_ops viommu_ops = { > + .capable = viommu_capable, > .domain_alloc = viommu_domain_alloc, > .domain_free = viommu_domain_free, > .attach_dev = viommu_attach_dev, > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index b95a6f8db6ff..1d24be667a03 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -94,6 +94,7 @@ enum iommu_cap { > transactions */ > IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */ > IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ > + IOMMU_CAP_VIOMMU, /* IOMMU can declar running in a VM */ > }; > > /* > -- > 2.25.1 >