From: Jason Gunthorpe <jgg@nvidia.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
Dave Jiang <dave.jiang@intel.com>, Vinod Koul <vkoul@kernel.org>,
Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
Jacob jun Pan <jacob.jun.pan@intel.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 08/12] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces
Date: Tue, 10 May 2022 12:23:30 -0300 [thread overview]
Message-ID: <20220510152330.GG49344@nvidia.com> (raw)
In-Reply-To: <20220510061738.2761430-9-baolu.lu@linux.intel.com>
On Tue, May 10, 2022 at 02:17:34PM +0800, Lu Baolu wrote:
> +/**
> + * iommu_sva_bind_device() - Bind a process address space to a device
> + * @dev: the device
> + * @mm: the mm to bind, caller must hold a reference to mm_users
> + * @drvdata: opaque data pointer to pass to bind callback
> + *
> + * Create a bond between device and address space, allowing the device to access
> + * the mm using the returned PASID. If a bond already exists between @device and
> + * @mm, it is returned and an additional reference is taken. Caller must call
> + * iommu_sva_unbind_device() to release each reference.
> + *
> + * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to
> + * initialize the required SVA features.
> + *
> + * On error, returns an ERR_PTR value.
> + */
> +struct iommu_sva *
> +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
> +{
> + int ret = -EINVAL;
> + struct iommu_sva *handle;
> + struct iommu_domain *domain;
> +
> + /*
> + * TODO: Remove the drvdata parameter after kernel PASID support is
> + * enabled for the idxd driver.
> + */
> + if (drvdata)
> + return ERR_PTR(-EOPNOTSUPP);
Why is this being left behind? Clean up the callers too please.
> + /* Allocate mm->pasid if necessary. */
> + ret = iommu_sva_alloc_pasid(mm, 1, (1U << dev->iommu->pasid_bits) - 1);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + mutex_lock(&iommu_sva_lock);
> + /* Search for an existing bond. */
> + handle = xa_load(&dev->iommu->sva_bonds, mm->pasid);
> + if (handle) {
> + refcount_inc(&handle->users);
> + goto out_success;
> + }
How can there be an existing bond?
dev->iommu is per-device
The device_group_immutable_singleton() insists on a single device
group
Basically 'sva_bonds' is the same thing as the group->pasid_array.
Assuming we leave room for multi-device groups this logic should just
be
group = iommu_group_get(dev);
if (!group)
return -ENODEV;
mutex_lock(&group->mutex);
domain = xa_load(&group->pasid_array, mm->pasid);
if (!domain || domain->type != IOMMU_DOMAIN_SVA || domain->mm != mm)
domain = iommu_sva_alloc_domain(dev, mm);
?
And stick the refcount in the sva_domain
Also, given the current arrangement it might make sense to have a
struct iommu_domain_sva given that no driver is wrappering this in
something else.
Jason
next prev parent reply other threads:[~2022-05-10 15:28 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-10 6:17 [PATCH v6 00/12] iommu: SVA and IOPF refactoring Lu Baolu
2022-05-10 6:17 ` [PATCH v6 01/12] dmaengine: idxd: Separate user and kernel pasid enabling Lu Baolu
2022-05-10 6:17 ` [PATCH v6 02/12] iommu: Add pasid_bits field in struct dev_iommu Lu Baolu
2022-05-10 14:34 ` Jason Gunthorpe
2022-05-11 2:25 ` Baolu Lu
2022-05-11 8:00 ` Jean-Philippe Brucker
2022-05-11 11:59 ` Jason Gunthorpe
2022-05-10 6:17 ` [PATCH v6 03/12] iommu: Add attach/detach_dev_pasid domain ops Lu Baolu
2022-05-10 14:02 ` Jason Gunthorpe
2022-05-11 2:32 ` Baolu Lu
2022-05-11 4:09 ` Tian, Kevin
2022-05-11 7:54 ` Jean-Philippe Brucker
2022-05-11 12:02 ` Jason Gunthorpe
2022-05-12 7:00 ` Jean-Philippe Brucker
2022-05-12 11:51 ` Jason Gunthorpe
2022-05-16 2:03 ` Baolu Lu
2022-05-10 6:17 ` [PATCH v6 04/12] iommu/sva: Basic data structures for SVA Lu Baolu
2022-05-10 6:17 ` [PATCH v6 05/12] iommu/vt-d: Remove SVM_FLAG_SUPERVISOR_MODE support Lu Baolu
2022-05-10 14:35 ` Jason Gunthorpe
2022-05-10 6:17 ` [PATCH v6 06/12] iommu/vt-d: Add SVA domain support Lu Baolu
2022-05-10 6:17 ` [PATCH v6 07/12] arm-smmu-v3/sva: " Lu Baolu
2022-05-10 6:17 ` [PATCH v6 08/12] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces Lu Baolu
2022-05-10 15:23 ` Jason Gunthorpe [this message]
2022-05-11 7:21 ` Baolu Lu
2022-05-11 14:53 ` Jason Gunthorpe
2022-05-12 3:02 ` Baolu Lu
2022-05-12 5:01 ` Tian, Kevin
2022-05-12 5:17 ` Baolu Lu
2022-05-12 5:44 ` Tian, Kevin
2022-05-12 6:16 ` Baolu Lu
2022-05-12 11:48 ` Jason Gunthorpe
2022-05-12 11:59 ` Baolu Lu
2022-05-12 12:03 ` Jason Gunthorpe
2022-05-12 12:47 ` Baolu Lu
2022-05-12 11:51 ` Jason Gunthorpe
2022-05-12 12:39 ` Baolu Lu
2022-05-10 6:17 ` [PATCH v6 09/12] iommu: Remove SVA related callbacks from iommu ops Lu Baolu
2022-05-10 6:17 ` [PATCH v6 10/12] iommu: Prepare IOMMU domain for IOPF Lu Baolu
2022-05-10 6:17 ` [PATCH v6 11/12] iommu: Per-domain I/O page fault handling Lu Baolu
2022-05-10 6:17 ` [PATCH v6 12/12] iommu: Rename iommu-sva-lib.{c,h} Lu Baolu
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