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From: Alex Williamson <alex.williamson@redhat.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Cornelia Huck <cohuck@redhat.com>,
	Kevin Tian <kevin.tian@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	Dave Jiang <dave.jiang@intel.com>, Liu Yi L <yi.l.liu@intel.com>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org
Subject: Re: [PATCH v3 1/4] iommu: Check IOMMU_DEV_FEAT_AUX feature in aux api's
Date: Wed, 29 Jul 2020 14:03:43 -0600
Message-ID: <20200729140343.2b7047b2@x1.home> (raw)
In-Reply-To: <20200714055703.5510-2-baolu.lu@linux.intel.com>

On Tue, 14 Jul 2020 13:57:00 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:

> The iommu aux-domain api's work only when IOMMU_DEV_FEAT_AUX is enabled
> for the device. Add this check to avoid misuse.

Shouldn't this really be the IOMMU driver's responsibility to test?  If
nothing else, iommu_dev_feature_enabled() needs to get the iommu_ops
from dev->bus->iommu_ops, which is presumably the same iommu_ops we're
then calling from domain->ops to attach/detach the device, so it'd be
more efficient for the IOMMU driver to error on devices that don't
support aux.  Thanks,

Alex

> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/iommu/iommu.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 1ed1e14a1f0c..e1fdd3531d65 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2725,11 +2725,13 @@ EXPORT_SYMBOL_GPL(iommu_dev_feature_enabled);
>   */
>  int iommu_aux_attach_device(struct iommu_domain *domain, struct device *dev)
>  {
> -	int ret = -ENODEV;
> +	int ret;
>  
> -	if (domain->ops->aux_attach_dev)
> -		ret = domain->ops->aux_attach_dev(domain, dev);
> +	if (!iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX) ||
> +	    !domain->ops->aux_attach_dev)
> +		return -ENODEV;
>  
> +	ret = domain->ops->aux_attach_dev(domain, dev);
>  	if (!ret)
>  		trace_attach_device_to_domain(dev);
>  
> @@ -2748,12 +2750,12 @@ EXPORT_SYMBOL_GPL(iommu_aux_detach_device);
>  
>  int iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev)
>  {
> -	int ret = -ENODEV;
> +	if (!iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX) ||
> +	    !domain->ops->aux_get_pasid)
> +		return -ENODEV;
>  
> -	if (domain->ops->aux_get_pasid)
> -		ret = domain->ops->aux_get_pasid(domain, dev);
> +	return domain->ops->aux_get_pasid(domain, dev);
>  
> -	return ret;
>  }
>  EXPORT_SYMBOL_GPL(iommu_aux_get_pasid);
>  


  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 [this message]
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
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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