linux-kernel - Re: [PATCH v2 7/8] iommu/vt-d: Delete supervisor/kernel SVA

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Date:   Tue, 29 Mar 2022 10:42:19 -0700
From:   Jacob Pan <jacob.jun.pan@...ux.intel.com>
To:     "Tian, Kevin" <kevin.tian@...el.com>
Cc:     "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Joerg Roedel <joro@...tes.org>,
        "Jason Gunthorpe" <jgg@...dia.com>,
        Christoph Hellwig <hch@...radead.org>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Jean-Philippe Brucker <jean-philippe@...aro.com>,
        "Pan, Jacob jun" <jacob.jun.pan@...el.com>,
        "Raj, Ashok" <ashok.raj@...el.com>,
        "Kumar, Sanjay K" <sanjay.k.kumar@...el.com>,
        "Jiang, Dave" <dave.jiang@...el.com>,
        "Luck, Tony" <tony.luck@...el.com>,
        "Zanussi, Tom" <tom.zanussi@...el.com>,
        "Williams, Dan J" <dan.j.williams@...el.com>,
        "Liu, Yi L" <yi.l.liu@...el.com>, jacob.jun.pan@...ux.intel.com
Subject: Re: [PATCH v2 7/8] iommu/vt-d: Delete supervisor/kernel SVA

Hi Kevin,

On Fri, 18 Mar 2022 06:16:58 +0000, "Tian, Kevin" <kevin.tian@...el.com>
wrote:

> > From: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> > Sent: Tuesday, March 15, 2022 1:07 PM
> > 
> > In-kernel DMA with PASID should use DMA API now, remove supervisor
> > PASID
> > SVA support. Remove special cases in bind mm and page request service.
> > 
> > Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>  
> 
> so you removed all the references to SVM_FLAG_SUPERVISOR_MODE
> but the definition is still kept in include/linux/intel-svm.h...
> 
Good catch, will remove.

> > ---
> >  drivers/iommu/intel/svm.c | 42 ++++++++-------------------------------
> >  1 file changed, 8 insertions(+), 34 deletions(-)
> > 
> > diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> > index 2c53689da461..37d6218f173b 100644
> > --- a/drivers/iommu/intel/svm.c
> > +++ b/drivers/iommu/intel/svm.c
> > @@ -516,11 +516,10 @@ static void intel_svm_free_pasid(struct mm_struct
> > *mm)
> > 
> >  static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
> >  					   struct device *dev,
> > -					   struct mm_struct *mm,
> > -					   unsigned int flags)
> > +					   struct mm_struct *mm)
> >  {
> >  	struct device_domain_info *info = get_domain_info(dev);
> > -	unsigned long iflags, sflags;
> > +	unsigned long iflags, sflags = 0;
> >  	struct intel_svm_dev *sdev;
> >  	struct intel_svm *svm;
> >  	int ret = 0;
> > @@ -533,16 +532,13 @@ static struct iommu_sva
> > *intel_svm_bind_mm(struct intel_iommu *iommu,
> > 
> >  		svm->pasid = mm->pasid;
> >  		svm->mm = mm;
> > -		svm->flags = flags;
> >  		INIT_LIST_HEAD_RCU(&svm->devs);
> > 
> > -		if (!(flags & SVM_FLAG_SUPERVISOR_MODE)) {
> > -			svm->notifier.ops = &intel_mmuops;
> > -			ret = mmu_notifier_register(&svm->notifier,
> > mm);
> > -			if (ret) {
> > -				kfree(svm);
> > -				return ERR_PTR(ret);
> > -			}
> > +		svm->notifier.ops = &intel_mmuops;
> > +		ret = mmu_notifier_register(&svm->notifier, mm);
> > +		if (ret) {
> > +			kfree(svm);
> > +			return ERR_PTR(ret);
> >  		}
> > 
> >  		ret = pasid_private_add(svm->pasid, svm);
> > @@ -583,8 +579,6 @@ static struct iommu_sva *intel_svm_bind_mm(struct
> > intel_iommu *iommu,
> >  	}
> > 
> >  	/* Setup the pasid table: */
> > -	sflags = (flags & SVM_FLAG_SUPERVISOR_MODE) ?
> > -			PASID_FLAG_SUPERVISOR_MODE : 0;
> >  	sflags |= cpu_feature_enabled(X86_FEATURE_LA57) ?
> > PASID_FLAG_FL5LP : 0;
> >  	spin_lock_irqsave(&iommu->lock, iflags);
> >  	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm-  
> > >pasid,  
> > @@ -957,7 +951,7 @@ static irqreturn_t prq_event_thread(int irq, void
> > *d)
> >  			 * to unbind the mm while any page faults are
> > outstanding.
> >  			 */
> >  			svm = pasid_private_find(req->pasid);
> > -			if (IS_ERR_OR_NULL(svm) || (svm->flags &
> > SVM_FLAG_SUPERVISOR_MODE))
> > +			if (IS_ERR_OR_NULL(svm))
> >  				goto bad_req;
> >  		}
> > 
> > @@ -1011,29 +1005,9 @@ static irqreturn_t prq_event_thread(int irq, void
> > *d)
> >  struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct
> > *mm, void *drvdata)
> >  {
> >  	struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
> > -	unsigned int flags = 0;
> >  	struct iommu_sva *sva;
> >  	int ret;
> > 
> > -	if (drvdata)
> > -		flags = *(unsigned int *)drvdata;
> > -
> > -	if (flags & SVM_FLAG_SUPERVISOR_MODE) {
> > -		if (!ecap_srs(iommu->ecap)) {
> > -			dev_err(dev, "%s: Supervisor PASID not
> > supported\n",
> > -				iommu->name);
> > -			return ERR_PTR(-EOPNOTSUPP);
> > -		}
> > -
> > -		if (mm) {
> > -			dev_err(dev, "%s: Supervisor PASID with user
> > provided mm\n",
> > -				iommu->name);
> > -			return ERR_PTR(-EINVAL);
> > -		}
> > -
> > -		mm = &init_mm;
> > -	}
> > -
> >  	mutex_lock(&pasid_mutex);
> >  	ret = intel_svm_alloc_pasid(dev, mm, flags);
> >  	if (ret) {
> > --
> > 2.25.1  
> 


Thanks,

Jacob