int intel_svm_bind_gpasid()

in intel/svm.c [321:461]

• 93 lines of code
• 21 McCabe index (conditional complexity)

int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
			  struct iommu_gpasid_bind_data *data)
{
	struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
	struct intel_svm_dev *sdev = NULL;
	struct dmar_domain *dmar_domain;
	struct device_domain_info *info;
	struct intel_svm *svm = NULL;
	unsigned long iflags;
	int ret = 0;

	if (WARN_ON(!iommu) || !data)
		return -EINVAL;

	if (data->format != IOMMU_PASID_FORMAT_INTEL_VTD)
		return -EINVAL;

	/* IOMMU core ensures argsz is more than the start of the union */
	if (data->argsz < offsetofend(struct iommu_gpasid_bind_data, vendor.vtd))
		return -EINVAL;

	/* Make sure no undefined flags are used in vendor data */
	if (data->vendor.vtd.flags & ~(IOMMU_SVA_VTD_GPASID_LAST - 1))
		return -EINVAL;

	if (!dev_is_pci(dev))
		return -ENOTSUPP;

	/* VT-d supports devices with full 20 bit PASIDs only */
	if (pci_max_pasids(to_pci_dev(dev)) != PASID_MAX)
		return -EINVAL;

	/*
	 * We only check host PASID range, we have no knowledge to check
	 * guest PASID range.
	 */
	if (data->hpasid <= 0 || data->hpasid >= PASID_MAX)
		return -EINVAL;

	info = get_domain_info(dev);
	if (!info)
		return -EINVAL;

	dmar_domain = to_dmar_domain(domain);

	mutex_lock(&pasid_mutex);
	ret = pasid_to_svm_sdev(dev, data->hpasid, &svm, &sdev);
	if (ret)
		goto out;

	if (sdev) {
		/*
		 * Do not allow multiple bindings of the same device-PASID since
		 * there is only one SL page tables per PASID. We may revisit
		 * once sharing PGD across domains are supported.
		 */
		dev_warn_ratelimited(dev, "Already bound with PASID %u\n",
				     svm->pasid);
		ret = -EBUSY;
		goto out;
	}

	if (!svm) {
		/* We come here when PASID has never been bond to a device. */
		svm = kzalloc(sizeof(*svm), GFP_KERNEL);
		if (!svm) {
			ret = -ENOMEM;
			goto out;
		}
		/* REVISIT: upper layer/VFIO can track host process that bind
		 * the PASID. ioasid_set = mm might be sufficient for vfio to
		 * check pasid VMM ownership. We can drop the following line
		 * once VFIO and IOASID set check is in place.
		 */
		svm->mm = get_task_mm(current);
		svm->pasid = data->hpasid;
		if (data->flags & IOMMU_SVA_GPASID_VAL) {
			svm->gpasid = data->gpasid;
			svm->flags |= SVM_FLAG_GUEST_PASID;
		}
		pasid_private_add(data->hpasid, svm);
		INIT_LIST_HEAD_RCU(&svm->devs);
		mmput(svm->mm);
	}
	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
	if (!sdev) {
		ret = -ENOMEM;
		goto out;
	}
	sdev->dev = dev;
	sdev->sid = PCI_DEVID(info->bus, info->devfn);
	sdev->iommu = iommu;

	/* Only count users if device has aux domains */
	if (iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX))
		sdev->users = 1;

	/* Set up device context entry for PASID if not enabled already */
	ret = intel_iommu_enable_pasid(iommu, sdev->dev);
	if (ret) {
		dev_err_ratelimited(dev, "Failed to enable PASID capability\n");
		kfree(sdev);
		goto out;
	}

	/*
	 * PASID table is per device for better security. Therefore, for
	 * each bind of a new device even with an existing PASID, we need to
	 * call the nested mode setup function here.
	 */
	spin_lock_irqsave(&iommu->lock, iflags);
	ret = intel_pasid_setup_nested(iommu, dev,
				       (pgd_t *)(uintptr_t)data->gpgd,
				       data->hpasid, &data->vendor.vtd, dmar_domain,
				       data->addr_width);
	spin_unlock_irqrestore(&iommu->lock, iflags);
	if (ret) {
		dev_err_ratelimited(dev, "Failed to set up PASID %llu in nested mode, Err %d\n",
				    data->hpasid, ret);
		/*
		 * PASID entry should be in cleared state if nested mode
		 * set up failed. So we only need to clear IOASID tracking
		 * data such that free call will succeed.
		 */
		kfree(sdev);
		goto out;
	}

	svm->flags |= SVM_FLAG_GUEST_MODE;

	init_rcu_head(&sdev->rcu);
	list_add_rcu(&sdev->list, &svm->devs);
 out:
	if (!IS_ERR_OR_NULL(svm) && list_empty(&svm->devs)) {
		pasid_private_remove(data->hpasid);
		kfree(svm);
	}

	mutex_unlock(&pasid_mutex);
	return ret;
}