linux-kernel - RE: [PATCH v6 08/15] iommu: Pass domain to sva_unbind

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Date:   Fri, 21 Aug 2020 00:18:40 +0000
From:   "Liu, Yi L" <yi.l.liu@...el.com>
To:     Alex Williamson <alex.williamson@...hat.com>
CC:     "eric.auger@...hat.com" <eric.auger@...hat.com>,
        "baolu.lu@...ux.intel.com" <baolu.lu@...ux.intel.com>,
        "joro@...tes.org" <joro@...tes.org>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        "jacob.jun.pan@...ux.intel.com" <jacob.jun.pan@...ux.intel.com>,
        "Raj, Ashok" <ashok.raj@...el.com>,
        "Tian, Jun J" <jun.j.tian@...el.com>,
        "Sun, Yi Y" <yi.y.sun@...el.com>,
        "jean-philippe@...aro.org" <jean-philippe@...aro.org>,
        "peterx@...hat.com" <peterx@...hat.com>,
        "Wu, Hao" <hao.wu@...el.com>,
        "stefanha@...il.com" <stefanha@...il.com>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v6 08/15] iommu: Pass domain to sva_unbind_gpasid()

Hi Alex,

> From: Alex Williamson <alex.williamson@...hat.com>
> Sent: Friday, August 21, 2020 5:06 AM
> 
> On Mon, 27 Jul 2020 23:27:37 -0700
> Liu Yi L <yi.l.liu@...el.com> wrote:
> 
> > From: Yi Sun <yi.y.sun@...el.com>
> >
> > Current interface is good enough for SVA virtualization on an assigned
> > physical PCI device, but when it comes to mediated devices, a physical
> > device may attached with multiple aux-domains. Also, for guest unbind,
> 
> s/may/may be/

got it.

> 
> > the PASID to be unbind should be allocated to the VM. This check
> > requires to know the ioasid_set which is associated with the domain.
> >
> > So this interface needs to pass in domain info. Then the iommu driver
> > is able to know which domain will be used for the 2nd stage
> > translation of the nesting mode and also be able to do PASID ownership
> > check. This patch passes @domain per the above reason. Also, the
> > prototype of &pasid is changed frnt" to "u32" as the below link.
> 
> s/frnt"/from an "int"/

got it.

> > https://lore.kernel.org/kvm/27ac7880-bdd3-2891-139e-b4a7cd18420b@redha
> > t.com/
> 
> This is really confusing, the link is to Eric's comment asking that the conversion from
> (at the time) int to ioasid_t be included in the commit log.  The text here implies that
> it's pointing to some sort of justification for the change, which it isn't.  It just notes
> that it happened, not why it happened, with a mostly irrelevant link.

really sorry, a mistake from me. it should be the below link.

[PATCH v6 01/12] iommu: Change type of pasid to u32
https://lore.kernel.org/linux-iommu/1594684087-61184-2-git-send-email-fenghua.yu@intel.com/

> > Cc: Kevin Tian <kevin.tian@...el.com>
> > CC: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> > Cc: Alex Williamson <alex.williamson@...hat.com>
> > Cc: Eric Auger <eric.auger@...hat.com>
> > Cc: Jean-Philippe Brucker <jean-philippe@...aro.org>
> > Cc: Joerg Roedel <joro@...tes.org>
> > Cc: Lu Baolu <baolu.lu@...ux.intel.com>
> > Reviewed-by: Eric Auger <eric.auger@...hat.com>
> > Signed-off-by: Yi Sun <yi.y.sun@...el.com>
> > Signed-off-by: Liu Yi L <yi.l.liu@...el.com>
> > ---
> > v5 -> v6:
> > *) use "u32" prototype for @pasid.
> > *) add review-by from Eric Auger.
> 
> I'd probably hold off on adding Eric's R-b given the additional change in this version
> FWIW.  Thanks,

ok, will hold on it. :-)

Regards,
Yi Liu

> Alex
> 
> > v2 -> v3:
> > *) pass in domain info only
> > *) use u32 for pasid instead of int type
> >
> > v1 -> v2:
> > *) added in v2.
> > ---
> >  drivers/iommu/intel/svm.c   | 3 ++-
> >  drivers/iommu/iommu.c       | 2 +-
> >  include/linux/intel-iommu.h | 3 ++-
> >  include/linux/iommu.h       | 3 ++-
> >  4 files changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> > index c27d16a..c85b8d5 100644
> > --- a/drivers/iommu/intel/svm.c
> > +++ b/drivers/iommu/intel/svm.c
> > @@ -436,7 +436,8 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain,
> struct device *dev,
> >  	return ret;
> >  }
> >
> > -int intel_svm_unbind_gpasid(struct device *dev, int pasid)
> > +int intel_svm_unbind_gpasid(struct iommu_domain *domain,
> > +			    struct device *dev, u32 pasid)
> >  {
> >  	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
> >  	struct intel_svm_dev *sdev;
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index
> > 1ce2a61..bee79d7 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -2145,7 +2145,7 @@ int iommu_sva_unbind_gpasid(struct iommu_domain
> *domain, struct device *dev,
> >  	if (unlikely(!domain->ops->sva_unbind_gpasid))
> >  		return -ENODEV;
> >
> > -	return domain->ops->sva_unbind_gpasid(dev, data->hpasid);
> > +	return domain->ops->sva_unbind_gpasid(domain, dev, data->hpasid);
> >  }
> >  EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
> >
> > diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> > index 0d0ab32..f98146b 100644
> > --- a/include/linux/intel-iommu.h
> > +++ b/include/linux/intel-iommu.h
> > @@ -738,7 +738,8 @@ extern int intel_svm_enable_prq(struct intel_iommu
> > *iommu);  extern int intel_svm_finish_prq(struct intel_iommu *iommu);
> > int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
> >  			  struct iommu_gpasid_bind_data *data); -int
> > intel_svm_unbind_gpasid(struct device *dev, int pasid);
> > +int intel_svm_unbind_gpasid(struct iommu_domain *domain,
> > +			    struct device *dev, u32 pasid);
> >  struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct *mm,
> >  				 void *drvdata);
> >  void intel_svm_unbind(struct iommu_sva *handle); diff --git
> > a/include/linux/iommu.h b/include/linux/iommu.h index b1ff702..80467fc
> > 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -303,7 +303,8 @@ struct iommu_ops {
> >  	int (*sva_bind_gpasid)(struct iommu_domain *domain,
> >  			struct device *dev, struct iommu_gpasid_bind_data *data);
> >
> > -	int (*sva_unbind_gpasid)(struct device *dev, int pasid);
> > +	int (*sva_unbind_gpasid)(struct iommu_domain *domain,
> > +				 struct device *dev, u32 pasid);
> >
> >  	int (*def_domain_type)(struct device *dev);
> >