Revert "vfio/pci: Register an iommu fault handler"

virt inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I61SPO
CVE: NA

--------------------------------

This reverts commit f7c0c57b.
Signed-off-by: NKunkun Jiang <jiangkunkun@huawei.com>
Reviewed-by: NKeqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/vfio/pci/vfio_pci.c

@@ -27,7 +27,6 @@
 #include <linux/vgaarb.h>
 #include <linux/nospec.h>
 #include <linux/sched/mm.h>
-#include <linux/circ_buf.h>
 
 #include "vfio_pci_private.h"
 
@@ -389,41 +388,6 @@ static const struct vfio_pci_regops vfio_pci_dma_fault_regops = {
 	.add_capability = vfio_pci_dma_fault_add_capability,
 };
 
-static int
-vfio_pci_iommu_dev_fault_handler(struct iommu_fault *fault, void *data)
-{
-	struct vfio_pci_device *vdev = (struct vfio_pci_device *)data;
-	struct vfio_region_dma_fault *reg =
-		(struct vfio_region_dma_fault *)vdev->fault_pages;
-	struct iommu_fault *new;
-	u32 head, tail, size;
-	int ret = -EINVAL;
-
-	if (WARN_ON(!reg))
-		return ret;
-
-	mutex_lock(&vdev->fault_queue_lock);
-
-	head = reg->head;
-	tail = reg->tail;
-	size = reg->nb_entries;
-
-	new = (struct iommu_fault *)(vdev->fault_pages + reg->offset +
-				     head * reg->entry_size);
-
-	if (CIRC_SPACE(head, tail, size) < 1) {
-		ret = -ENOSPC;
-		goto unlock;
-	}
-
-	*new = *fault;
-	reg->head = (head + 1) % size;
-	ret = 0;
-unlock:
-	mutex_unlock(&vdev->fault_queue_lock);
-	return ret;
-}
-
 #define DMA_FAULT_RING_LENGTH 512
 
 static int vfio_pci_dma_fault_init(struct vfio_pci_device *vdev)
@@ -468,13 +432,6 @@ static int vfio_pci_dma_fault_init(struct vfio_pci_device *vdev)
 	header->entry_size = sizeof(struct iommu_fault);
 	header->nb_entries = DMA_FAULT_RING_LENGTH;
 	header->offset = sizeof(struct vfio_region_dma_fault);
-
-	ret = iommu_register_device_fault_handler(&vdev->pdev->dev,
-					vfio_pci_iommu_dev_fault_handler,
-					vdev);
-	if (ret) /* the dma fault region is freed in vfio_pci_disable() */
-		goto out;
-
 	return 0;
 out:
 	kfree(vdev->fault_pages);
@@ -598,7 +555,7 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
 	struct pci_dev *pdev = vdev->pdev;
 	struct vfio_pci_dummy_resource *dummy_res, *tmp;
 	struct vfio_pci_ioeventfd *ioeventfd, *ioeventfd_tmp;
-	int i, bar, ret;
+	int i, bar;
 
 	/* Stop the device from further DMA */
 	pci_clear_master(pdev);
@@ -607,9 +564,6 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
 				VFIO_IRQ_SET_ACTION_TRIGGER,
 				vdev->irq_type, 0, 0, NULL);
 
-	ret = iommu_unregister_device_fault_handler(&vdev->pdev->dev);
-	WARN_ON(ret == -EBUSY);
-
 	/* Device closed, don't need mutex here */
 	list_for_each_entry_safe(ioeventfd, ioeventfd_tmp,
 				 &vdev->ioeventfds_list, next) {