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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jacob Pan <jacob.jun.pan@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: Wed, 15 Jul 2020 08:47:36 +0800
Message-ID: <b5b22e01-4a51-8dfe-9ba4-aeca783740f1@linux.intel.com> (raw)
In-Reply-To: <20200714093909.1ab93c9e@jacob-builder>

Hi Jacob,

On 7/15/20 12:39 AM, Jacob Pan wrote:
> 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()
> 

It has been changed in PATCH 4/4:

static int vfio_iommu_attach_group(struct vfio_domain *domain,
                                    struct vfio_group *group)
{
         if (group->mdev_group)
                 return iommu_aux_attach_group(domain->domain,
                                               group->iommu_group,
                                               group->iommu_device);
         else
                 return iommu_attach_group(domain->domain, 
group->iommu_group);
}

So, for both normal domain and aux-domain, we use the same concept:
attach a domain to a group.

Best regards,
baolu
_______________________________________________
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 [this message]
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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