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Date:   Mon, 28 Oct 2019 15:46:11 -0700
From:   Jacob Pan <jacob.jun.pan@linux.intel.com>
To:     "Tian, Kevin" <kevin.tian@intel.com>
Cc:     "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        "David Woodhouse" <dwmw2@infradead.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        "Liu, Yi L" <yi.l.liu@intel.com>,
        "Raj, Ashok" <ashok.raj@intel.com>,
        Christoph Hellwig <hch@infradead.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Eric Auger <eric.auger@redhat.com>,
        jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH v7 04/11] iommu/vt-d: Replace Intel specific PASID
 allocator with IOASID
Message-ID: <20191028154611.5c9979fd@jacob-builder>
In-Reply-To: <AADFC41AFE54684AB9EE6CBC0274A5D19D5CDC87@SHSMSX104.ccr.corp.intel.com>
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        <1571946904-86776-5-git-send-email-jacob.jun.pan@linux.intel.com>
        <AADFC41AFE54684AB9EE6CBC0274A5D19D5CDC87@SHSMSX104.ccr.corp.intel.com>
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On Fri, 25 Oct 2019 06:41:16 +0000
"Tian, Kevin" <kevin.tian@intel.com> wrote:

> > From: Jacob Pan [mailto:jacob.jun.pan@linux.intel.com]
> > Sent: Friday, October 25, 2019 3:55 AM
> > 
> > Make use of generic IOASID code to manage PASID allocation,
> > free, and lookup. Replace Intel specific code.
> > 
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>  
> 
> better push this patch separately. It's a generic cleanup.
> 
True but might be more efficient to have this cleanup patch paved way.
Since the follow up new guest SVA code uses the new API. So I wanted to
get rid of the old code completely.
> > ---
> >  drivers/iommu/intel-iommu.c | 12 ++++++------
> >  drivers/iommu/intel-pasid.c | 36
> > ------------------------------------ drivers/iommu/intel-svm.c   |
> > 39 +++++++++++++++++++++++---------------- 3 files changed, 29
> > insertions(+), 58 deletions(-)
> > 
> > diff --git a/drivers/iommu/intel-iommu.c
> > b/drivers/iommu/intel-iommu.c index ced1d89ef977..2ea09b988a23
> > 100644 --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -5311,7 +5311,7 @@ static void auxiliary_unlink_device(struct
> > dmar_domain *domain,
> >  	domain->auxd_refcnt--;
> > 
> >  	if (!domain->auxd_refcnt && domain->default_pasid > 0)
> > -		intel_pasid_free_id(domain->default_pasid);
> > +		ioasid_free(domain->default_pasid);
> >  }
> > 
> >  static int aux_domain_add_dev(struct dmar_domain *domain,
> > @@ -5329,10 +5329,10 @@ static int aux_domain_add_dev(struct
> > dmar_domain *domain,
> >  	if (domain->default_pasid <= 0) {
> >  		int pasid;
> > 
> > -		pasid = intel_pasid_alloc_id(domain, PASID_MIN,
> > -
> > pci_max_pasids(to_pci_dev(dev)),
> > -					     GFP_KERNEL);
> > -		if (pasid <= 0) {
> > +		/* No private data needed for the default pasid */
> > +		pasid = ioasid_alloc(NULL, PASID_MIN,
> > pci_max_pasids(to_pci_dev(dev)) - 1,
> > +				NULL);
> > +		if (pasid == INVALID_IOASID) {
> >  			pr_err("Can't allocate default pasid\n");
> >  			return -ENODEV;
> >  		}
> > @@ -5368,7 +5368,7 @@ static int aux_domain_add_dev(struct
> > dmar_domain *domain,
> >  	spin_unlock(&iommu->lock);
> >  	spin_unlock_irqrestore(&device_domain_lock, flags);
> >  	if (!domain->auxd_refcnt && domain->default_pasid > 0)
> > -		intel_pasid_free_id(domain->default_pasid);
> > +		ioasid_free(domain->default_pasid);
> > 
> >  	return ret;
> >  }
> > diff --git a/drivers/iommu/intel-pasid.c
> > b/drivers/iommu/intel-pasid.c index d81e857d2b25..e79d680fe300
> > 100644 --- a/drivers/iommu/intel-pasid.c
> > +++ b/drivers/iommu/intel-pasid.c
> > @@ -26,42 +26,6 @@
> >   */
> >  static DEFINE_SPINLOCK(pasid_lock);
> >  u32 intel_pasid_max_id = PASID_MAX;
> > -static DEFINE_IDR(pasid_idr);
> > -
> > -int intel_pasid_alloc_id(void *ptr, int start, int end, gfp_t gfp)
> > -{
> > -	int ret, min, max;
> > -
> > -	min = max_t(int, start, PASID_MIN);
> > -	max = min_t(int, end, intel_pasid_max_id);
> > -
> > -	WARN_ON(in_interrupt());
> > -	idr_preload(gfp);
> > -	spin_lock(&pasid_lock);
> > -	ret = idr_alloc(&pasid_idr, ptr, min, max, GFP_ATOMIC);
> > -	spin_unlock(&pasid_lock);
> > -	idr_preload_end();
> > -
> > -	return ret;
> > -}
> > -
> > -void intel_pasid_free_id(int pasid)
> > -{
> > -	spin_lock(&pasid_lock);
> > -	idr_remove(&pasid_idr, pasid);
> > -	spin_unlock(&pasid_lock);
> > -}
> > -
> > -void *intel_pasid_lookup_id(int pasid)
> > -{
> > -	void *p;
> > -
> > -	spin_lock(&pasid_lock);
> > -	p = idr_find(&pasid_idr, pasid);
> > -	spin_unlock(&pasid_lock);
> > -
> > -	return p;
> > -}
> > 
> >  int vcmd_alloc_pasid(struct intel_iommu *iommu, unsigned int
> > *pasid) {
> > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
> > index 9b159132405d..a9a7f85a09bc 100644
> > --- a/drivers/iommu/intel-svm.c
> > +++ b/drivers/iommu/intel-svm.c
> > @@ -17,6 +17,7 @@
> >  #include <linux/dmar.h>
> >  #include <linux/interrupt.h>
> >  #include <linux/mm_types.h>
> > +#include <linux/ioasid.h>
> >  #include <asm/page.h>
> > 
> >  #include "intel-pasid.h"
> > @@ -318,16 +319,15 @@ int intel_svm_bind_mm(struct device *dev, int
> > *pasid, int flags, struct svm_dev_
> >  		if (pasid_max > intel_pasid_max_id)
> >  			pasid_max = intel_pasid_max_id;
> > 
> > -		/* Do not use PASID 0 in caching mode (virtualised
> > IOMMU) */
> > -		ret = intel_pasid_alloc_id(svm,
> > -					   !!cap_caching_mode(iommu->cap),
> > -					   pasid_max - 1,
> > GFP_KERNEL);
> > -		if (ret < 0) {
> > +		/* Do not use PASID 0, reserved for RID to PASID */
> > +		svm->pasid = ioasid_alloc(NULL, PASID_MIN,
> > +					pasid_max - 1, svm);
> > +		if (svm->pasid == INVALID_IOASID) {
> >  			kfree(svm);
> >  			kfree(sdev);
> > +			ret = ENOSPC;
> >  			goto out;
> >  		}
> > -		svm->pasid = ret;
> >  		svm->notifier.ops = &intel_mmuops;
> >  		svm->mm = mm;
> >  		svm->flags = flags;
> > @@ -337,7 +337,7 @@ int intel_svm_bind_mm(struct device *dev, int
> > *pasid, int flags, struct svm_dev_
> >  		if (mm) {
> >  			ret =
> > mmu_notifier_register(&svm->notifier, mm); if (ret) {
> > -				intel_pasid_free_id(svm->pasid);
> > +				ioasid_free(svm->pasid);
> >  				kfree(svm);
> >  				kfree(sdev);
> >  				goto out;
> > @@ -353,7 +353,7 @@ int intel_svm_bind_mm(struct device *dev, int
> > *pasid, int flags, struct svm_dev_
> >  		if (ret) {
> >  			if (mm)
> >  				mmu_notifier_unregister(&svm->notifier,
> > mm);
> > -			intel_pasid_free_id(svm->pasid);
> > +			ioasid_free(svm->pasid);
> >  			kfree(svm);
> >  			kfree(sdev);
> >  			goto out;
> > @@ -401,7 +401,12 @@ int intel_svm_unbind_mm(struct device *dev, int
> > pasid)
> >  	if (!iommu)
> >  		goto out;
> > 
> > -	svm = intel_pasid_lookup_id(pasid);
> > +	svm = ioasid_find(NULL, pasid, NULL);
> > +	if (IS_ERR(svm)) {
> > +		ret = PTR_ERR(svm);
> > +		goto out;
> > +	}
> > +
> >  	if (!svm)
> >  		goto out;
> > 
> > @@ -423,7 +428,9 @@ int intel_svm_unbind_mm(struct device *dev, int
> > pasid)
> >  				kfree_rcu(sdev, rcu);
> > 
> >  				if (list_empty(&svm->devs)) {
> > -
> > intel_pasid_free_id(svm->pasid);
> > +					/* Clear private data so
> > that free pass check */
> > +
> > ioasid_set_data(svm->pasid, NULL);
> > +					ioasid_free(svm->pasid);
> >  					if (svm->mm)
> > 
> > 	mmu_notifier_unregister(&svm->notifier, svm->mm);
> > 
> > @@ -458,10 +465,11 @@ int intel_svm_is_pasid_valid(struct device
> > *dev, int pasid)
> >  	if (!iommu)
> >  		goto out;
> > 
> > -	svm = intel_pasid_lookup_id(pasid);
> > -	if (!svm)
> > +	svm = ioasid_find(NULL, pasid, NULL);
> > +	if (IS_ERR(svm)) {
> > +		ret = PTR_ERR(svm);
> >  		goto out;
> > -
> > +	}
> >  	/* init_mm is used in this case */
> >  	if (!svm->mm)
> >  		ret = 1;
> > @@ -568,13 +576,12 @@ static irqreturn_t prq_event_thread(int irq,
> > void *d)
> > 
> >  		if (!svm || svm->pasid != req->pasid) {
> >  			rcu_read_lock();
> > -			svm = intel_pasid_lookup_id(req->pasid);
> > +			svm = ioasid_find(NULL, req->pasid, NULL);
> >  			/* It *can't* go away, because the driver
> > is not permitted
> >  			 * to unbind the mm while any page faults
> > are outstanding.
> >  			 * So we only need RCU to protect the
> > internal idr code. */
> >  			rcu_read_unlock();
> > -
> > -			if (!svm) {
> > +			if (IS_ERR(svm) || !svm) {
> >  				pr_err("%s: Page request for
> > invalid PASID %d: %08llx %08llx\n",
> >  				       iommu->name, req->pasid,
> > ((unsigned long long *)req)[0],
> >  				       ((unsigned long long
> > *)req)[1]); --
> > 2.7.4  
> 

[Jacob Pan]