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iommufd: Allow binding to a noiommu device
Allow iommufd to bind devices without an IOMMU (noiommu mode) by creating a dummy igroup for such devices and skipping hwpt operations. This enables noiommu devices to operate through the same iommufd API as IOMMU- capable devices. Link: https://patch.msgid.link/r/2c6cf6ab1564426050e637863c9b0d3b25541c63.1783360051.git.jacob.pan@linux.microsoft.com Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Yi Liu <yi.l.liu@intel.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Pranjal Shrivastava <praan@google.com> Signed-off-by: Jacob Pan <jacob.pan@linux.microsoft.com> Fixes: 2c6cf6ab1564 ("iommufd: Allow binding to a noiommu device") Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe
parent
cfa8214875
commit
072f454c38
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@ -23,6 +23,19 @@ struct iommufd_attach {
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struct xarray device_array;
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};
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/*
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* Detect a noiommu device for the cdev path. We check dev->iommu rather than
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* using device_iommu_mapped() (which checks dev->iommu_group) because when
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* both group and cdev interfaces coexist, the group path assigns a fake
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* noiommu iommu_group to the device. That would cause device_iommu_mapped()
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* to return true and hide the noiommu case from the cdev path. dev->iommu is
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* reliably NULL when no IOMMU driver is managing the device.
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*/
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static bool iommufd_device_is_noiommu(struct iommufd_device *idev)
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{
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return IS_ENABLED(CONFIG_IOMMUFD_NOIOMMU) && !idev->dev->iommu;
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}
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static void iommufd_group_release(struct kref *kref)
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{
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struct iommufd_group *igroup =
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@ -30,9 +43,11 @@ static void iommufd_group_release(struct kref *kref)
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WARN_ON(!xa_empty(&igroup->pasid_attach));
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xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group), igroup,
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NULL, GFP_KERNEL);
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iommu_group_put(igroup->group);
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if (igroup->group) {
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xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group),
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igroup, NULL, GFP_KERNEL);
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iommu_group_put(igroup->group);
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}
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mutex_destroy(&igroup->lock);
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kfree(igroup);
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}
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@ -197,32 +212,20 @@ void iommufd_device_destroy(struct iommufd_object *obj)
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struct iommufd_device *idev =
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container_of(obj, struct iommufd_device, obj);
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iommu_device_release_dma_owner(idev->dev);
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/* igroup is NULL when destroy called during bind error cleanup */
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if (!idev->igroup)
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return;
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if (!iommufd_device_is_noiommu(idev))
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iommu_device_release_dma_owner(idev->dev);
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iommufd_put_group(idev->igroup);
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if (!iommufd_selftest_is_mock_dev(idev->dev))
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iommufd_ctx_put(idev->ictx);
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}
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/**
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* iommufd_device_bind - Bind a physical device to an iommu fd
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* @ictx: iommufd file descriptor
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* @dev: Pointer to a physical device struct
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* @id: Output ID number to return to userspace for this device
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*
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* A successful bind establishes an ownership over the device and returns
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* struct iommufd_device pointer, otherwise returns error pointer.
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*
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* A driver using this API must set driver_managed_dma and must not touch
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* the device until this routine succeeds and establishes ownership.
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*
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* Binding a PCI device places the entire RID under iommufd control.
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*
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* The caller must undo this with iommufd_device_unbind()
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*/
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struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
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struct device *dev, u32 *id)
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static int iommufd_bind_iommu(struct iommufd_device *idev)
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{
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struct iommufd_device *idev;
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struct iommufd_ctx *ictx = idev->ictx;
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struct device *dev = idev->dev;
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struct iommufd_group *igroup;
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int rc;
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@ -231,11 +234,11 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
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* to restore cache coherency.
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*/
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if (!device_iommu_capable(dev, IOMMU_CAP_CACHE_COHERENCY))
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return ERR_PTR(-EINVAL);
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return -EINVAL;
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igroup = iommufd_get_group(ictx, dev);
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if (IS_ERR(igroup))
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return ERR_CAST(igroup);
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return PTR_ERR(igroup);
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/*
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* For historical compat with VFIO the insecure interrupt path is
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@ -261,21 +264,77 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
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if (rc)
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goto out_group_put;
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idev = iommufd_object_alloc(ictx, idev, IOMMUFD_OBJ_DEVICE);
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if (IS_ERR(idev)) {
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rc = PTR_ERR(idev);
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goto out_release_owner;
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}
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idev->ictx = ictx;
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if (!iommufd_selftest_is_mock_dev(dev))
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iommufd_ctx_get(ictx);
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idev->dev = dev;
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idev->enforce_cache_coherency =
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device_iommu_capable(dev, IOMMU_CAP_ENFORCE_CACHE_COHERENCY);
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/* The calling driver is a user until iommufd_device_unbind() */
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refcount_inc(&idev->obj.users);
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/* igroup refcount moves into iommufd_device */
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idev->igroup = igroup;
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idev->enforce_cache_coherency =
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device_iommu_capable(dev, IOMMU_CAP_ENFORCE_CACHE_COHERENCY);
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return 0;
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out_group_put:
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iommufd_put_group(igroup);
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return rc;
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}
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/*
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* Noiommu devices have no real IOMMU group. Create a dummy igroup so that
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* internal code paths that expect idev->igroup to be present still work.
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* A NULL igroup->group distinguishes this from a real IOMMU-backed group.
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*/
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static int iommufd_bind_noiommu(struct iommufd_device *idev)
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{
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struct iommufd_group *igroup;
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igroup = iommufd_alloc_group(idev->ictx, NULL);
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if (IS_ERR(igroup))
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return PTR_ERR(igroup);
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idev->igroup = igroup;
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return 0;
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}
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/**
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* iommufd_device_bind - Bind a physical device to an iommu fd
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* @ictx: iommufd file descriptor
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* @dev: Pointer to a physical device struct
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* @id: Output ID number to return to userspace for this device
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*
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* A successful bind establishes an ownership over the device and returns
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* struct iommufd_device pointer, otherwise returns error pointer.
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*
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* A driver using this API must set driver_managed_dma and must not touch
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* the device until this routine succeeds and establishes ownership.
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*
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* Binding a PCI device places the entire RID under iommufd control.
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*
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* The caller must undo this with iommufd_device_unbind()
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*/
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struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
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struct device *dev, u32 *id)
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{
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struct iommufd_device *idev;
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int rc;
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idev = iommufd_object_alloc(ictx, idev, IOMMUFD_OBJ_DEVICE);
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if (IS_ERR(idev))
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return idev;
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idev->ictx = ictx;
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idev->dev = dev;
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if (!iommufd_device_is_noiommu(idev))
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rc = iommufd_bind_iommu(idev);
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else
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rc = iommufd_bind_noiommu(idev);
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if (rc)
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goto err_out;
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/*
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* Take a ctx reference after bind succeeds. This must happen here
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* so that iommufd_device_destroy() can handle partial initialization
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*/
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if (!iommufd_selftest_is_mock_dev(dev))
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iommufd_ctx_get(ictx);
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/* The calling driver is a user until iommufd_device_unbind() */
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refcount_inc(&idev->obj.users);
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/*
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* If the caller fails after this success it must call
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@ -287,11 +346,14 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
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*id = idev->obj.id;
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return idev;
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out_release_owner:
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iommu_device_release_dma_owner(dev);
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out_group_put:
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iommufd_put_group(igroup);
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err_out:
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/*
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* iommufd_device_destroy() handles partially initialized idev,
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* so iommufd_object_abort_and_destroy() is safe to call here.
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*/
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iommufd_object_abort_and_destroy(ictx, &idev->obj);
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return ERR_PTR(rc);
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}
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EXPORT_SYMBOL_NS_GPL(iommufd_device_bind, "IOMMUFD");
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@ -512,6 +574,9 @@ static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
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if (rc)
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return rc;
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if (iommufd_device_is_noiommu(idev))
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return 0;
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handle = kzalloc_obj(*handle);
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if (!handle)
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return -ENOMEM;
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@ -552,6 +617,9 @@ static void iommufd_hwpt_detach_device(struct iommufd_hw_pagetable *hwpt,
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{
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struct iommufd_attach_handle *handle;
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if (iommufd_device_is_noiommu(idev))
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return;
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handle = iommufd_device_get_attach_handle(idev, pasid);
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if (pasid == IOMMU_NO_PASID)
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iommu_detach_group_handle(hwpt->domain, idev->igroup->group);
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@ -577,6 +645,9 @@ static int iommufd_hwpt_replace_device(struct iommufd_device *idev,
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if (rc)
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return rc;
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if (iommufd_device_is_noiommu(idev))
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return 0;
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old_handle = iommufd_device_get_attach_handle(idev, pasid);
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handle = kzalloc_obj(*handle);
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@ -607,7 +678,8 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
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struct iommufd_device *idev, ioasid_t pasid)
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{
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struct iommufd_hwpt_paging *hwpt_paging = find_hwpt_paging(hwpt);
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bool attach_resv = hwpt_paging && pasid == IOMMU_NO_PASID;
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bool attach_resv = hwpt_paging && pasid == IOMMU_NO_PASID &&
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!iommufd_device_is_noiommu(idev);
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struct iommufd_group *igroup = idev->igroup;
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struct iommufd_hw_pagetable *old_hwpt;
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struct iommufd_attach *attach;
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@ -786,7 +858,8 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid,
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struct iommufd_hw_pagetable *hwpt)
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{
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struct iommufd_hwpt_paging *hwpt_paging = find_hwpt_paging(hwpt);
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bool attach_resv = hwpt_paging && pasid == IOMMU_NO_PASID;
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bool attach_resv = hwpt_paging && pasid == IOMMU_NO_PASID &&
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!iommufd_device_is_noiommu(idev);
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struct iommufd_hwpt_paging *old_hwpt_paging;
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struct iommufd_group *igroup = idev->igroup;
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struct iommufd_hw_pagetable *old_hwpt;
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@ -1578,6 +1651,11 @@ int iommufd_get_hw_info(struct iommufd_ucmd *ucmd)
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if (IS_ERR(idev))
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return PTR_ERR(idev);
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if (iommufd_device_is_noiommu(idev)) {
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rc = -EOPNOTSUPP;
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goto out_put;
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}
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ops = dev_iommu_ops(idev->dev);
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if (ops->hw_info) {
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data = ops->hw_info(idev->dev, &data_len, &cmd->out_data_type);
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