IOMMU Archive on lore.kernel.org
 help / color / Atom feed
From: "Tian, Kevin" <kevin.tian@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>,
	Lu Baolu <baolu.lu@linux.intel.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
	"Jiang, Dave" <dave.jiang@intel.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Cornelia Huck <cohuck@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	Robin Murphy <robin.murphy@arm.com>
Subject: RE: [PATCH v3 3/4] iommu: Add iommu_aux_get_domain_for_dev()
Date: Wed, 29 Jul 2020 23:49:20 +0000
Message-ID: <MWHPR11MB1645736D9ED91A95D1D4519A8C700@MWHPR11MB1645.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20200729142507.182cd18a@x1.home>

> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Thursday, July 30, 2020 4:25 AM
> 
> On Tue, 14 Jul 2020 13:57:02 +0800
> Lu Baolu <baolu.lu@linux.intel.com> wrote:
> 
> > The device driver needs an API to get its aux-domain. A typical usage
> > scenario is:
> >
> >         unsigned long pasid;
> >         struct iommu_domain *domain;
> >         struct device *dev = mdev_dev(mdev);
> >         struct device *iommu_device = vfio_mdev_get_iommu_device(dev);
> >
> >         domain = iommu_aux_get_domain_for_dev(dev);
> >         if (!domain)
> >                 return -ENODEV;
> >
> >         pasid = iommu_aux_get_pasid(domain, iommu_device);
> >         if (pasid <= 0)
> >                 return -EINVAL;
> >
> >          /* Program the device context */
> >          ....
> >
> > This adds an API for such use case.
> >
> > Suggested-by: Alex Williamson <alex.williamson@redhat.com>
> > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> > ---
> >  drivers/iommu/iommu.c | 18 ++++++++++++++++++
> >  include/linux/iommu.h |  7 +++++++
> >  2 files changed, 25 insertions(+)
> >
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > index cad5a19ebf22..434bf42b6b9b 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -2817,6 +2817,24 @@ void iommu_aux_detach_group(struct
> iommu_domain *domain,
> >  }
> >  EXPORT_SYMBOL_GPL(iommu_aux_detach_group);
> >
> > +struct iommu_domain *iommu_aux_get_domain_for_dev(struct device
> *dev)
> > +{
> > +	struct iommu_domain *domain = NULL;
> > +	struct iommu_group *group;
> > +
> > +	group = iommu_group_get(dev);
> > +	if (!group)
> > +		return NULL;
> > +
> > +	if (group->aux_domain_attached)
> > +		domain = group->domain;
> 
> Why wouldn't the aux domain flag be on the domain itself rather than
> the group?  Then if we wanted sanity checking in patch 1/ we'd only
> need to test the flag on the object we're provided.
> 
> If we had such a flag, we could create an iommu_domain_is_aux()
> function and then simply use iommu_get_domain_for_dev() and test that
> it's an aux domain in the example use case.  It seems like that would

IOMMU layer manages domains per parent device. Here given a
dev (of mdev), we need a way to find its associated domain under its
parent device. And we cannot simply use iommu_get_domain_for_dev
on the parent device of the mdev, as it will give us the primary domain
of parent device. 

Thanks
Kevin

> resolve the jump from a domain to an aux-domain just as well as adding
> this separate iommu_aux_get_domain_for_dev() interface.  The is_aux
> test might also be useful in other cases too.  Thanks,
> 
> Alex
> 
> > +
> > +	iommu_group_put(group);
> > +
> > +	return domain;
> > +}
> > +EXPORT_SYMBOL_GPL(iommu_aux_get_domain_for_dev);
> > +
> >  /**
> >   * iommu_sva_bind_device() - Bind a process address space to a device
> >   * @dev: the device
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 9506551139ab..cda6cef7579e 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -639,6 +639,7 @@ int iommu_aux_attach_group(struct
> iommu_domain *domain,
> >  			   struct iommu_group *group, struct device *dev);
> >  void iommu_aux_detach_group(struct iommu_domain *domain,
> >  			   struct iommu_group *group, struct device *dev);
> > +struct iommu_domain *iommu_aux_get_domain_for_dev(struct device
> *dev);
> >
> >  struct iommu_sva *iommu_sva_bind_device(struct device *dev,
> >  					struct mm_struct *mm,
> > @@ -1040,6 +1041,12 @@ iommu_aux_detach_group(struct
> iommu_domain *domain,
> >  {
> >  }
> >
> > +static inline struct iommu_domain *
> > +iommu_aux_get_domain_for_dev(struct device *dev)
> > +{
> > +	return NULL;
> > +}
> > +
> >  static inline struct iommu_sva *
> >  iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void
> *drvdata)
> >  {

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14  5:56 [PATCH v3 0/4] iommu aux-domain APIs extensions Lu Baolu
2020-07-14  5:57 ` [PATCH v3 1/4] iommu: Check IOMMU_DEV_FEAT_AUX feature in aux api's Lu Baolu
2020-07-29 20:03   ` Alex Williamson
2020-07-30  1:46     ` Lu Baolu
2020-07-14  5:57 ` [PATCH v3 2/4] iommu: Add iommu_aux_at(de)tach_group() Lu Baolu
2020-07-14 16:39   ` Jacob Pan
2020-07-15  0:47     ` Lu Baolu
2020-07-15 16:01       ` Jacob Pan
2020-07-16  1:07         ` Lu Baolu
2020-07-29 20:03           ` Alex Williamson
2020-07-29 23:34             ` Tian, Kevin
2020-07-30 19:46               ` Alex Williamson
2020-07-31  5:47                 ` Lu Baolu
2020-07-31 18:05                   ` Alex Williamson
2020-08-03  1:57                     ` Lu Baolu
2020-07-14  5:57 ` [PATCH v3 3/4] iommu: Add iommu_aux_get_domain_for_dev() Lu Baolu
2020-07-29 20:25   ` Alex Williamson
2020-07-29 23:49     ` Tian, Kevin [this message]
2020-07-30 20:17       ` Alex Williamson
2020-07-31  0:26         ` Tian, Kevin
2020-07-31  2:17         ` Tian, Kevin
2020-07-31  6:30     ` Lu Baolu
2020-07-31 18:14       ` Alex Williamson
2020-08-03  2:15         ` Lu Baolu
2020-07-14  5:57 ` [PATCH v3 4/4] vfio/type1: Use iommu_aux_at(de)tach_group() APIs Lu Baolu
2020-07-14  8:25   ` Christoph Hellwig
2020-07-14 16:29     ` Jacob Pan
2020-07-15  1:00       ` Lu Baolu
2020-07-15  1:23         ` Tian, Kevin
2020-07-29 20:32   ` Alex Williamson
2020-07-30  2:41     ` Lu Baolu
2020-07-30 21:17       ` Alex Williamson
2020-07-31  1:37         ` Lu Baolu
2020-07-30  9:36   ` Liu, Yi L
2020-07-31  1:39     ` Lu Baolu
2020-07-23 13:55 ` [PATCH v3 0/4] iommu aux-domain APIs extensions Lu Baolu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=MWHPR11MB1645736D9ED91A95D1D4519A8C700@MWHPR11MB1645.namprd11.prod.outlook.com \
    --to=kevin.tian@intel.com \
    --cc=alex.williamson@redhat.com \
    --cc=ashok.raj@intel.com \
    --cc=baolu.lu@linux.intel.com \
    --cc=cohuck@redhat.com \
    --cc=dave.jiang@intel.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jean-philippe@linaro.org \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=robin.murphy@arm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

IOMMU Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-iommu/0 linux-iommu/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-iommu linux-iommu/ https://lore.kernel.org/linux-iommu \
		iommu@lists.linux-foundation.org
	public-inbox-index linux-iommu

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.linux-foundation.lists.iommu


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git