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[209.132.180.67]) by mx.google.com with ESMTP id l5si14108324edb.341.2019.11.18.13.43.51; Mon, 18 Nov 2019 13:44:15 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726775AbfKRVmp (ORCPT + 99 others); Mon, 18 Nov 2019 16:42:45 -0500 Received: from mga07.intel.com ([134.134.136.100]:14214 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726647AbfKRVmp (ORCPT ); Mon, 18 Nov 2019 16:42:45 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Nov 2019 13:42:44 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,321,1569308400"; d="scan'208";a="209211756" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga006.jf.intel.com with ESMTP; 18 Nov 2019 13:42:44 -0800 Date: Mon, 18 Nov 2019 13:47:19 -0800 From: Jacob Pan To: Auger Eric Cc: iommu@lists.linux-foundation.org, LKML , Joerg Roedel , Lu Baolu , David Woodhouse , "Tian, Kevin" , Raj Ashok , Yi Liu , jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v2 02/10] iommu/vt-d: Fix CPU and IOMMU SVM feature matching checks Message-ID: <20191118134719.6835981b@jacob-builder> In-Reply-To: <26d1e79b-3a16-0a8f-895e-e2c41c8d3b28@redhat.com> References: <1574106153-45867-1-git-send-email-jacob.jun.pan@linux.intel.com> <1574106153-45867-3-git-send-email-jacob.jun.pan@linux.intel.com> <26d1e79b-3a16-0a8f-895e-e2c41c8d3b28@redhat.com> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 18 Nov 2019 21:33:34 +0100 Auger Eric wrote: > Hi Jacob, > > On 11/18/19 8:42 PM, Jacob Pan wrote: > > The current code checks CPU and IOMMU feature set for SVM support > > but the result is never stored nor used. Therefore, SVM can still > > be used even when these checks failed. > "SVM can still be used even when these checks failed". What were the > consequences if it happened? Does it fix this cleanly now. > > The consequence is DMA cannot reach above 48-bit virtual address range when CPU does 5-level and IOMMU can only do 4-level. With is fix, svm_bind_mm will fail in the first place to prevent SVM use by DMA. > > This patch consolidates code for checking PASID, CPU vs. IOMMU > > paging mode compatibility, as well as provides specific error > > messages for each failed checks.> > > Signed-off-by: Jacob Pan > > Acked-by: Lu Baolu > > --- > > drivers/iommu/intel-iommu.c | 10 ++-------- > > drivers/iommu/intel-svm.c | 40 > > +++++++++++++++++++++++++++------------- > > include/linux/intel-iommu.h | 4 +++- 3 files changed, 32 > > insertions(+), 22 deletions(-) > > > > diff --git a/drivers/iommu/intel-iommu.c > > b/drivers/iommu/intel-iommu.c index 3f974919d3bd..d598168e410d > > 100644 --- a/drivers/iommu/intel-iommu.c > > +++ b/drivers/iommu/intel-iommu.c > > @@ -3289,10 +3289,7 @@ static int __init init_dmars(void) > > > > if (!ecap_pass_through(iommu->ecap)) > > hw_pass_through = 0; > > -#ifdef CONFIG_INTEL_IOMMU_SVM > > - if (pasid_supported(iommu)) > > - intel_svm_init(iommu); > > -#endif > > + intel_svm_check(iommu); > > } > > > > /* > > @@ -4471,10 +4468,7 @@ static int intel_iommu_add(struct > > dmar_drhd_unit *dmaru) if (ret) > > goto out; > > > > -#ifdef CONFIG_INTEL_IOMMU_SVM > > - if (pasid_supported(iommu)) > > - intel_svm_init(iommu); > > -#endif > > + intel_svm_check(iommu); > > > > if (dmaru->ignored) { > > /* > > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c > > index 9b159132405d..716c543488f6 100644 > > --- a/drivers/iommu/intel-svm.c > > +++ b/drivers/iommu/intel-svm.c > > @@ -23,19 +23,6 @@ > > > > static irqreturn_t prq_event_thread(int irq, void *d); > > > > -int intel_svm_init(struct intel_iommu *iommu) > > -{ > > - if (cpu_feature_enabled(X86_FEATURE_GBPAGES) && > > - !cap_fl1gp_support(iommu->cap)) > > - return -EINVAL; > > - > > - if (cpu_feature_enabled(X86_FEATURE_LA57) && > > - !cap_5lp_support(iommu->cap)) > > - return -EINVAL; > > - > > - return 0; > > -} > > - > > #define PRQ_ORDER 0 > > > > int intel_svm_enable_prq(struct intel_iommu *iommu) > > @@ -99,6 +86,33 @@ int intel_svm_finish_prq(struct intel_iommu > > *iommu) return 0; > > } > > > > +static inline bool intel_svm_capable(struct intel_iommu *iommu) > > +{ > > + return iommu->flags & VTD_FLAG_SVM_CAPABLE; > > +} > > + > > +void intel_svm_check(struct intel_iommu *iommu) > > +{ > > + if (!pasid_supported(iommu)) > > + return; > > + > > + if (cpu_feature_enabled(X86_FEATURE_GBPAGES) && > > + !cap_fl1gp_support(iommu->cap)) { > > + pr_err("%s SVM disabled, incompatible 1GB page > > capability\n", > > + iommu->name); > nit: is it really an error or just a warning? I think it is an error in that there is an illegal configuration. It is mostly for vIOMMU, we expect native HW should have these features matched. > > + return; > > + } > > + > > + if (cpu_feature_enabled(X86_FEATURE_LA57) && > > + !cap_5lp_support(iommu->cap)) { > > + pr_err("%s SVM disabled, incompatible paging > > mode\n", > > + iommu->name); > > + return; > > + } > > + > > + iommu->flags |= VTD_FLAG_SVM_CAPABLE; > > +} > > + > > static void intel_flush_svm_range_dev (struct intel_svm *svm, > > struct intel_svm_dev *sdev, unsigned long address, unsigned long > > pages, int ih) { > > diff --git a/include/linux/intel-iommu.h > > b/include/linux/intel-iommu.h index 63118991824c..7dcfa1c4a844 > > 100644 --- a/include/linux/intel-iommu.h > > +++ b/include/linux/intel-iommu.h > > @@ -657,7 +657,7 @@ void iommu_flush_write_buffer(struct > > intel_iommu *iommu); int intel_iommu_enable_pasid(struct > > intel_iommu *iommu, struct device *dev); > > #ifdef CONFIG_INTEL_IOMMU_SVM > > -int intel_svm_init(struct intel_iommu *iommu); > > +extern void intel_svm_check(struct intel_iommu *iommu); > > extern int intel_svm_enable_prq(struct intel_iommu *iommu); > > extern int intel_svm_finish_prq(struct intel_iommu *iommu); > > > > @@ -685,6 +685,8 @@ struct intel_svm { > > }; > > > > extern struct intel_iommu *intel_svm_device_to_iommu(struct device > > *dev); +#else > > +static inline void intel_svm_check(struct intel_iommu *iommu) {} > > #endif > > > > #ifdef CONFIG_INTEL_IOMMU_DEBUGFS > > > Besides, > Reviewed-by: Eric Auger > > Thanks > > Eric > [Jacob Pan]