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From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Kevin Tian <kevin.tian@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	kvm@vger.kernel.org, Cornelia Huck <cohuck@redhat.com>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	Alex Williamson <alex.williamson@redhat.com>,
	Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v3 2/4] iommu: Add iommu_aux_at(de)tach_group()
Date: Tue, 14 Jul 2020 09:39:09 -0700
Message-ID: <20200714093909.1ab93c9e@jacob-builder> (raw)
In-Reply-To: <20200714055703.5510-3-baolu.lu@linux.intel.com>

On Tue, 14 Jul 2020 13:57:01 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:

> This adds two new aux-domain APIs for a use case like vfio/mdev where
> sub-devices derived from an aux-domain capable device are created and
> put in an iommu_group.
> 
> /**
>  * iommu_aux_attach_group - attach an aux-domain to an iommu_group
> which
>  *                          contains sub-devices (for example mdevs)
> derived
>  *                          from @dev.
>  * @domain: an aux-domain;
>  * @group:  an iommu_group which contains sub-devices derived from
> @dev;
>  * @dev:    the physical device which supports IOMMU_DEV_FEAT_AUX.
>  *
>  * Returns 0 on success, or an error value.
>  */
> int iommu_aux_attach_group(struct iommu_domain *domain,
>                            struct iommu_group *group,
>                            struct device *dev)
> 
> /**
>  * iommu_aux_detach_group - detach an aux-domain from an iommu_group
>  *
>  * @domain: an aux-domain;
>  * @group:  an iommu_group which contains sub-devices derived from
> @dev;
>  * @dev:    the physical device which supports IOMMU_DEV_FEAT_AUX.
>  *
>  * @domain must have been attached to @group via
> iommu_aux_attach_group(). */
> void iommu_aux_detach_group(struct iommu_domain *domain,
>                             struct iommu_group *group,
>                             struct device *dev)
> 
> It also adds a flag in the iommu_group data structure to identify
> an iommu_group with aux-domain attached from those normal ones.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/iommu/iommu.c | 58
> +++++++++++++++++++++++++++++++++++++++++++ include/linux/iommu.h |
> 17 +++++++++++++ 2 files changed, 75 insertions(+)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index e1fdd3531d65..cad5a19ebf22 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -45,6 +45,7 @@ struct iommu_group {
>  	struct iommu_domain *default_domain;
>  	struct iommu_domain *domain;
>  	struct list_head entry;
> +	unsigned int aux_domain_attached:1;
>  };
>  
>  struct group_device {
> @@ -2759,6 +2760,63 @@ int iommu_aux_get_pasid(struct iommu_domain
> *domain, struct device *dev) }
>  EXPORT_SYMBOL_GPL(iommu_aux_get_pasid);
>  
> +/**
> + * iommu_aux_attach_group - attach an aux-domain to an iommu_group
> which
> + *                          contains sub-devices (for example mdevs)
> derived
> + *                          from @dev.
> + * @domain: an aux-domain;
> + * @group:  an iommu_group which contains sub-devices derived from
> @dev;
> + * @dev:    the physical device which supports IOMMU_DEV_FEAT_AUX.
> + *
> + * Returns 0 on success, or an error value.
> + */
> +int iommu_aux_attach_group(struct iommu_domain *domain,
> +			   struct iommu_group *group, struct device
> *dev) +{
> +	int ret = -EBUSY;
> +
> +	mutex_lock(&group->mutex);
> +	if (group->domain)
> +		goto out_unlock;
> +
Perhaps I missed something but are we assuming only one mdev per mdev
group? That seems to change the logic where vfio does:
iommu_group_for_each_dev()
	iommu_aux_attach_device()

> +	ret = iommu_aux_attach_device(domain, dev);
> +	if (!ret) {
> +		group->domain = domain;
> +		group->aux_domain_attached = true;
> +	}
> +
> +out_unlock:
> +	mutex_unlock(&group->mutex);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_aux_attach_group);
> +
> +/**
> + * iommu_aux_detach_group - detach an aux-domain from an iommu_group
> + *
> + * @domain: an aux-domain;
> + * @group:  an iommu_group which contains sub-devices derived from
> @dev;
> + * @dev:    the physical device which supports IOMMU_DEV_FEAT_AUX.
> + *
> + * @domain must have been attached to @group via
> iommu_aux_attach_group().
> + */
> +void iommu_aux_detach_group(struct iommu_domain *domain,
> +			    struct iommu_group *group, struct device
> *dev) +{
> +	mutex_lock(&group->mutex);
> +
> +	if (WARN_ON(!group->aux_domain_attached || group->domain !=
> domain))
> +		goto out_unlock;
> +
> +	iommu_aux_detach_device(domain, dev);
> +	group->aux_domain_attached = false;
> +	group->domain = NULL;
> +
> +out_unlock:
> +	mutex_unlock(&group->mutex);
> +}
> +EXPORT_SYMBOL_GPL(iommu_aux_detach_group);
> +
>  /**
>   * 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 5657d4fef9f2..9506551139ab 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -635,6 +635,10 @@ bool iommu_dev_feature_enabled(struct device
> *dev, enum iommu_dev_features f); int iommu_aux_attach_device(struct
> iommu_domain *domain, struct device *dev); void
> iommu_aux_detach_device(struct iommu_domain *domain, struct device
> *dev); int iommu_aux_get_pasid(struct iommu_domain *domain, struct
> device *dev); +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_sva *iommu_sva_bind_device(struct device *dev,
>  					struct mm_struct *mm,
> @@ -1023,6 +1027,19 @@ iommu_aux_get_pasid(struct iommu_domain
> *domain, struct device *dev) return -ENODEV;
>  }
>  
> +static inline int
> +iommu_aux_attach_group(struct iommu_domain *domain,
> +		       struct iommu_group *group, struct device *dev)
> +{
> +	return -ENODEV;
> +}
> +
> +static inline void
> +iommu_aux_detach_group(struct iommu_domain *domain,
> +		       struct iommu_group *group, struct device *dev)
> +{
> +}
> +
>  static inline struct iommu_sva *
>  iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void
> *drvdata) {

[Jacob Pan]
_______________________________________________
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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 [this message]
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
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

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