vfio-pci: Fault mmaps to enable vma tracking (11c4cd07) · Commits · 戴 / test

drivers/vfio/pci/vfio_pci.c

+74 −2

Original line number	Diff line number	Diff line
		@@ -1299,6 +1299,70 @@ static ssize_t vfio_pci_write(void device_data, const char __user buf,
		return vfio_pci_rw(device_data, (char __user *)buf, count, ppos, true);
		}

		static int vfio_pci_add_vma(struct vfio_pci_device *vdev,
		struct vm_area_struct *vma)
		{
		struct vfio_pci_mmap_vma *mmap_vma;

		mmap_vma = kmalloc(sizeof(*mmap_vma), GFP_KERNEL);
		if (!mmap_vma)
		return -ENOMEM;

		mmap_vma->vma = vma;

		mutex_lock(&vdev->vma_lock);
		list_add(&mmap_vma->vma_next, &vdev->vma_list);
		mutex_unlock(&vdev->vma_lock);

		return 0;
		}

		/*
		* Zap mmaps on open so that we can fault them in on access and therefore
		* our vma_list only tracks mappings accessed since last zap.
		*/
		static void vfio_pci_mmap_open(struct vm_area_struct *vma)
		{
		zap_vma_ptes(vma, vma->vm_start, vma->vm_end - vma->vm_start);
		}

		static void vfio_pci_mmap_close(struct vm_area_struct *vma)
		{
		struct vfio_pci_device *vdev = vma->vm_private_data;
		struct vfio_pci_mmap_vma *mmap_vma;

		mutex_lock(&vdev->vma_lock);
		list_for_each_entry(mmap_vma, &vdev->vma_list, vma_next) {
		if (mmap_vma->vma == vma) {
		list_del(&mmap_vma->vma_next);
		kfree(mmap_vma);
		break;
		}
		}
		mutex_unlock(&vdev->vma_lock);
		}

		static vm_fault_t vfio_pci_mmap_fault(struct vm_fault *vmf)
		{
		struct vm_area_struct *vma = vmf->vma;
		struct vfio_pci_device *vdev = vma->vm_private_data;

		if (vfio_pci_add_vma(vdev, vma))
		return VM_FAULT_OOM;

		if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
		vma->vm_end - vma->vm_start, vma->vm_page_prot))
		return VM_FAULT_SIGBUS;

		return VM_FAULT_NOPAGE;
		}

		static const struct vm_operations_struct vfio_pci_mmap_ops = {
		.open = vfio_pci_mmap_open,
		.close = vfio_pci_mmap_close,
		.fault = vfio_pci_mmap_fault,
		};

		static int vfio_pci_mmap(void device_data, struct vm_area_struct vma)
		{
		struct vfio_pci_device *vdev = device_data;
		@@ -1357,8 +1421,14 @@ static int vfio_pci_mmap(void device_data, struct vm_area_struct vma)
		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
		vma->vm_pgoff = (pci_resource_start(pdev, index) >> PAGE_SHIFT) + pgoff;

		return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
		req_len, vma->vm_page_prot);
		/*
		* See remap_pfn_range(), called from vfio_pci_fault() but we can't
		* change vm_flags within the fault handler. Set them now.
		*/
		vma->vm_flags \|= VM_IO \| VM_PFNMAP \| VM_DONTEXPAND \| VM_DONTDUMP;
		vma->vm_ops = &vfio_pci_mmap_ops;

		return 0;
		}

		static void vfio_pci_request(void *device_data, unsigned int count)
		@@ -1608,6 +1678,8 @@ static int vfio_pci_probe(struct pci_dev pdev, const struct pci_device_id id)
		spin_lock_init(&vdev->irqlock);
		mutex_init(&vdev->ioeventfds_lock);
		INIT_LIST_HEAD(&vdev->ioeventfds_list);
		mutex_init(&vdev->vma_lock);
		INIT_LIST_HEAD(&vdev->vma_list);

		ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
		if (ret)

drivers/vfio/pci/vfio_pci_private.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -92,6 +92,11 @@ struct vfio_pci_vf_token {
		int users;
		};

		struct vfio_pci_mmap_vma {
		struct vm_area_struct *vma;
		struct list_head vma_next;
		};

		struct vfio_pci_device {
		struct pci_dev *pdev;
		void __iomem *barmap[PCI_STD_NUM_BARS];
		@@ -132,6 +137,8 @@ struct vfio_pci_device {
		struct list_head ioeventfds_list;
		struct vfio_pci_vf_token *vf_token;
		struct notifier_block nb;
		struct mutex vma_lock;
		struct list_head vma_list;
		};

		#define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX)

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