From: Alex Williamson <alex.williamson@redhat.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,
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 14:25:07 -0600 [thread overview]
Message-ID: <20200729142507.182cd18a@x1.home> (raw)
In-Reply-To: <20200714055703.5510-4-baolu.lu@linux.intel.com>
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
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)
> {
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next prev parent reply other threads:[~2020-07-29 20:25 UTC|newest]
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 [this message]
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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