From: Baolu Lu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
Christoph Hellwig <hch@infradead.org>,
Bjorn Helgaas <bhelgaas@google.com>,
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>,
Zhangfei Gao <zhangfei.gao@linaro.org>,
Zhu Tony <tony.zhu@intel.com>,
iommu@lists.linux.dev, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org,
Jean-Philippe Brucker <jean-philippe@linaro.org>
Subject: Re: [PATCH v11 09/13] iommu/sva: Refactoring iommu_sva_bind/unbind_device()
Date: Tue, 23 Aug 2022 18:12:44 +0800 [thread overview]
Message-ID: <83069b7d-3dc8-8b72-246b-264389cac072@linux.intel.com> (raw)
In-Reply-To: <Yv5Bf7+59po6K/1h@nvidia.com>
On 2022/8/18 21:41, Jason Gunthorpe wrote:
> On Wed, Aug 17, 2022 at 09:20:20AM +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
>> + *
>> + * 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)
>> +{
>> + struct iommu_domain *domain;
>> + struct iommu_sva *bond;
>
> This is called handle below, pick one name please
Updated.
>
>> + ioasid_t max_pasids;
>> + int ret;
>> +
>> + max_pasids = dev->iommu->max_pasids;
>> + if (!max_pasids)
>> + return ERR_PTR(-EOPNOTSUPP);
>> +
>> + /* Allocate mm->pasid if necessary. */
>> + ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1);
>> + if (ret)
>> + return ERR_PTR(ret);
>> +
>> + bond = kzalloc(sizeof(*bond), GFP_KERNEL);
>> + if (!bond)
>> + return ERR_PTR(-ENOMEM);
>> +
>> + mutex_lock(&iommu_sva_lock);
>> + /* Search for an existing domain. */
>> + domain = iommu_get_domain_for_dev_pasid(dev, mm->pasid);
>> + if (domain) {
>
> This isn't safe, or sane. A driver could have attached something to
> this PASID that is not a SVA domain and thus not protected by the
> iommu_sva_lock.
>
> At a minimum you should add a type match to
> iommu_get_domain_for_dev_pasid(), eg to confirm it is a SVA domain and
> do that check under the xa_lock of the pasid xarray.
>
> And then the general idea is that SVA domain attach/detach must hold
> this janky global lock.
Make sense. I will add this logic.
>
>> + refcount_inc(&domain->users);
>
> This atomic is always processed under the iommu_sva_lock, so it
> doesn't need to be an atomic anymore.
Will change it to an integer.
>
> Otherwise this design looks OK to me too
Thank you very much for your suggestions.
Best regards,
baolu
next prev parent reply other threads:[~2022-08-23 10:12 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-17 1:20 [PATCH v11 00/13] iommu: SVA and IOPF refactoring Lu Baolu
2022-08-17 1:20 ` [PATCH v11 01/13] iommu: Add max_pasids field in struct iommu_device Lu Baolu
2022-08-17 1:20 ` [PATCH v11 02/13] iommu: Add max_pasids field in struct dev_iommu Lu Baolu
2022-08-17 1:20 ` [PATCH v11 03/13] iommu: Remove SVM_FLAG_SUPERVISOR_MODE support Lu Baolu
2022-08-17 1:20 ` [PATCH v11 04/13] PCI: Allow PASID only when ACS enforced on upstreaming path Lu Baolu
2022-08-17 21:17 ` Bjorn Helgaas
2022-08-17 22:48 ` Jason Gunthorpe
2022-08-18 11:55 ` Baolu Lu
2022-08-18 11:53 ` Baolu Lu
2022-08-18 23:00 ` Bjorn Helgaas
2022-08-22 7:43 ` Ethan Zhao
2022-08-23 7:05 ` Baolu Lu
2022-08-24 16:23 ` Bjorn Helgaas
2022-08-18 13:04 ` Jason Gunthorpe
2022-08-23 7:10 ` Baolu Lu
2022-08-17 1:20 ` [PATCH v11 05/13] iommu: Add attach/detach_dev_pasid iommu interface Lu Baolu
2022-08-18 13:33 ` Jason Gunthorpe
2022-08-23 7:30 ` Baolu Lu
2022-08-17 1:20 ` [PATCH v11 06/13] iommu: Add IOMMU SVA domain support Lu Baolu
2022-08-17 1:20 ` [PATCH v11 07/13] iommu/vt-d: Add " Lu Baolu
2022-08-18 13:36 ` Jason Gunthorpe
2022-08-23 7:33 ` Baolu Lu
2022-08-17 1:20 ` [PATCH v11 08/13] arm-smmu-v3/sva: " Lu Baolu
2022-08-17 1:20 ` [PATCH v11 09/13] iommu/sva: Refactoring iommu_sva_bind/unbind_device() Lu Baolu
2022-08-18 13:41 ` Jason Gunthorpe
2022-08-23 10:12 ` Baolu Lu [this message]
2022-08-17 1:20 ` [PATCH v11 10/13] iommu: Remove SVA related callbacks from iommu ops Lu Baolu
2022-08-17 1:20 ` [PATCH v11 11/13] iommu: Prepare IOMMU domain for IOPF Lu Baolu
2022-08-17 1:20 ` [PATCH v11 12/13] iommu: Per-domain I/O page fault handling Lu Baolu
2022-08-17 1:20 ` [PATCH v11 13/13] iommu: Rename iommu-sva-lib.{c,h} Lu Baolu
2022-08-22 4:49 ` [PATCH v11 00/13] iommu: SVA and IOPF refactoring Zhangfei Gao
2022-08-23 7:00 ` Baolu Lu
2022-08-26 4:17 ` Baolu Lu
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