Messages in this thread | | | Subject | Re: [PATCH v4 20/22] iommu/vt-d: Add bind guest PASID support | From | Lu Baolu <> | Date | Fri, 5 Jul 2019 10:21:27 +0800 |
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Hi Jacob,
On 6/28/19 4:22 AM, Jacob Pan wrote: >>> + } >>> + refcount_set(&svm->refs, 0); >>> + ioasid_set_data(data->hpasid, svm); >>> + INIT_LIST_HEAD_RCU(&svm->devs); >>> + INIT_LIST_HEAD(&svm->list); >>> + >>> + mmput(svm->mm); >>> + } >>> + sdev = kzalloc(sizeof(*sdev), GFP_KERNEL); >>> + if (!sdev) { >>> + ret = -ENOMEM; >>> + goto out; >> I think you need to clean up svm if its device list is empty here, as >> you said above: >> > No, we come here only if the device list is not empty and the new > device to bind is different than any existing device in the list. If we > cannot allocate memory for the new device, should not free the existing > SVM, right? >
I'm sorry, but the code doesn't show this. We come here even an svm data structure was newly created with an empty device list. I post the code below to ensure that we are reading a same piece of code.
mutex_lock(&pasid_mutex); svm = ioasid_find(NULL, data->hpasid, NULL); if (IS_ERR(svm)) { ret = PTR_ERR(svm); goto out; } if (svm) { /* * If we found svm for the PASID, there must be at * least one device bond, otherwise svm should be freed. */ BUG_ON(list_empty(&svm->devs));
for_each_svm_dev() { /* In case of multiple sub-devices of the same pdev assigned, we should * allow multiple bind calls with the same PASID and pdev. */ sdev->users++; goto out; } } else { /* 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. */ 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; } refcount_set(&svm->refs, 0); ioasid_set_data(data->hpasid, svm); INIT_LIST_HEAD_RCU(&svm->devs); INIT_LIST_HEAD(&svm->list);
mmput(svm->mm); } sdev = kzalloc(sizeof(*sdev), GFP_KERNEL); if (!sdev) { ret = -ENOMEM; goto out; } sdev->dev = dev; sdev->users = 1;
Best regards, Baolu
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