1 files changed, 66 insertions, 205 deletions

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 80cae87fff36..987c7921affa 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1610,100 +1610,20 @@ ssize_t vfio_pci_core_write(struct vfio_device *core_vdev, const char __user *bu
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_write);
 
-/* Return 1 on zap and vma_lock acquired, 0 on contention (only with @try) */
-static int vfio_pci_zap_and_vma_lock(struct vfio_pci_core_device *vdev, bool try)
+static void vfio_pci_zap_bars(struct vfio_pci_core_device *vdev)
 {
-	struct vfio_pci_mmap_vma *mmap_vma, *tmp;
+	struct vfio_device *core_vdev = &vdev->vdev;
+	loff_t start = VFIO_PCI_INDEX_TO_OFFSET(VFIO_PCI_BAR0_REGION_INDEX);
+	loff_t end = VFIO_PCI_INDEX_TO_OFFSET(VFIO_PCI_ROM_REGION_INDEX);
+	loff_t len = end - start;
 
-	/*
-	 * Lock ordering:
-	 * vma_lock is nested under mmap_lock for vm_ops callback paths.
-	 * The memory_lock semaphore is used by both code paths calling
-	 * into this function to zap vmas and the vm_ops.fault callback
-	 * to protect the memory enable state of the device.
-	 *
-	 * When zapping vmas we need to maintain the mmap_lock => vma_lock
-	 * ordering, which requires using vma_lock to walk vma_list to
-	 * acquire an mm, then dropping vma_lock to get the mmap_lock and
-	 * reacquiring vma_lock.  This logic is derived from similar
-	 * requirements in uverbs_user_mmap_disassociate().
-	 *
-	 * mmap_lock must always be the top-level lock when it is taken.
-	 * Therefore we can only hold the memory_lock write lock when
-	 * vma_list is empty, as we'd need to take mmap_lock to clear
-	 * entries.  vma_list can only be guaranteed empty when holding
-	 * vma_lock, thus memory_lock is nested under vma_lock.
-	 *
-	 * This enables the vm_ops.fault callback to acquire vma_lock,
-	 * followed by memory_lock read lock, while already holding
-	 * mmap_lock without risk of deadlock.
-	 */
-	while (1) {
-		struct mm_struct *mm = NULL;
-
-		if (try) {
-			if (!mutex_trylock(&vdev->vma_lock))
-				return 0;
-		} else {
-			mutex_lock(&vdev->vma_lock);
-		}
-		while (!list_empty(&vdev->vma_list)) {
-			mmap_vma = list_first_entry(&vdev->vma_list,
-						    struct vfio_pci_mmap_vma,
-						    vma_next);
-			mm = mmap_vma->vma->vm_mm;
-			if (mmget_not_zero(mm))
-				break;
-
-			list_del(&mmap_vma->vma_next);
-			kfree(mmap_vma);
-			mm = NULL;
-		}
-		if (!mm)
-			return 1;
-		mutex_unlock(&vdev->vma_lock);
-
-		if (try) {
-			if (!mmap_read_trylock(mm)) {
-				mmput(mm);
-				return 0;
-			}
-		} else {
-			mmap_read_lock(mm);
-		}
-		if (try) {
-			if (!mutex_trylock(&vdev->vma_lock)) {
-				mmap_read_unlock(mm);
-				mmput(mm);
-				return 0;
-			}
-		} else {
-			mutex_lock(&vdev->vma_lock);
-		}
-		list_for_each_entry_safe(mmap_vma, tmp,
-					 &vdev->vma_list, vma_next) {
-			struct vm_area_struct *vma = mmap_vma->vma;
-
-			if (vma->vm_mm != mm)
-				continue;
-
-			list_del(&mmap_vma->vma_next);
-			kfree(mmap_vma);
-
-			zap_vma_ptes(vma, vma->vm_start,
-				     vma->vm_end - vma->vm_start);
-		}
-		mutex_unlock(&vdev->vma_lock);
-		mmap_read_unlock(mm);
-		mmput(mm);
-	}
+	unmap_mapping_range(core_vdev->inode->i_mapping, start, len, true);
 }
 
 void vfio_pci_zap_and_down_write_memory_lock(struct vfio_pci_core_device *vdev)
 {
-	vfio_pci_zap_and_vma_lock(vdev, false);
 	down_write(&vdev->memory_lock);
-	mutex_unlock(&vdev->vma_lock);
+	vfio_pci_zap_bars(vdev);
 }
 
 u16 vfio_pci_memory_lock_and_enable(struct vfio_pci_core_device *vdev)
@@ -1725,99 +1645,56 @@ void vfio_pci_memory_unlock_and_restore(struct vfio_pci_core_device *vdev, u16 c
 	up_write(&vdev->memory_lock);
 }
 
-/* Caller holds vma_lock */
-static int __vfio_pci_add_vma(struct vfio_pci_core_device *vdev,
-			      struct vm_area_struct *vma)
-{
-	struct vfio_pci_mmap_vma *mmap_vma;
-
-	mmap_vma = kmalloc(sizeof(*mmap_vma), GFP_KERNEL_ACCOUNT);
-	if (!mmap_vma)
-		return -ENOMEM;
-
-	mmap_vma->vma = vma;
-	list_add(&mmap_vma->vma_next, &vdev->vma_list);
-
-	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)
+static unsigned long vma_to_pfn(struct vm_area_struct *vma)
 {
 	struct vfio_pci_core_device *vdev = vma->vm_private_data;
-	struct vfio_pci_mmap_vma *mmap_vma;
+	int index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT);
+	u64 pgoff;
 
-	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);
+	pgoff = vma->vm_pgoff &
+		((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
+
+	return (pci_resource_start(vdev->pdev, index) >> PAGE_SHIFT) + pgoff;
 }
 
 static vm_fault_t vfio_pci_mmap_fault(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct vfio_pci_core_device *vdev = vma->vm_private_data;
-	struct vfio_pci_mmap_vma *mmap_vma;
-	vm_fault_t ret = VM_FAULT_NOPAGE;
+	unsigned long pfn, pgoff = vmf->pgoff - vma->vm_pgoff;
+	unsigned long addr = vma->vm_start;
+	vm_fault_t ret = VM_FAULT_SIGBUS;
+
+	pfn = vma_to_pfn(vma);
 
-	mutex_lock(&vdev->vma_lock);
 	down_read(&vdev->memory_lock);
 
-	/*
-	 * Memory region cannot be accessed if the low power feature is engaged
-	 * or memory access is disabled.
-	 */
-	if (vdev->pm_runtime_engaged || !__vfio_pci_memory_enabled(vdev)) {
-		ret = VM_FAULT_SIGBUS;
-		goto up_out;
-	}
+	if (vdev->pm_runtime_engaged || !__vfio_pci_memory_enabled(vdev))
+		goto out_unlock;
+
+	ret = vmf_insert_pfn(vma, vmf->address, pfn + pgoff);
+	if (ret & VM_FAULT_ERROR)
+		goto out_unlock;
 
 	/*
-	 * We populate the whole vma on fault, so we need to test whether
-	 * the vma has already been mapped, such as for concurrent faults
-	 * to the same vma.  io_remap_pfn_range() will trigger a BUG_ON if
-	 * we ask it to fill the same range again.
+	 * Pre-fault the remainder of the vma, abort further insertions and
+	 * supress error if fault is encountered during pre-fault.
 	 */
-	list_for_each_entry(mmap_vma, &vdev->vma_list, vma_next) {
-		if (mmap_vma->vma == vma)
-			goto up_out;
-	}
-
-	if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
-			       vma->vm_end - vma->vm_start,
-			       vma->vm_page_prot)) {
-		ret = VM_FAULT_SIGBUS;
-		zap_vma_ptes(vma, vma->vm_start, vma->vm_end - vma->vm_start);
-		goto up_out;
-	}
+	for (; addr < vma->vm_end; addr += PAGE_SIZE, pfn++) {
+		if (addr == vmf->address)
+			continue;
 
-	if (__vfio_pci_add_vma(vdev, vma)) {
-		ret = VM_FAULT_OOM;
-		zap_vma_ptes(vma, vma->vm_start, vma->vm_end - vma->vm_start);
+		if (vmf_insert_pfn(vma, addr, pfn) & VM_FAULT_ERROR)
+			break;
 	}
 
-up_out:
+out_unlock:
 	up_read(&vdev->memory_lock);
-	mutex_unlock(&vdev->vma_lock);
+
 	return ret;
 }
 
 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,
 };
 
@@ -1880,11 +1757,12 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
 
 	vma->vm_private_data = vdev;
 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-	vma->vm_pgoff = (pci_resource_start(pdev, index) >> PAGE_SHIFT) + pgoff;
+	vma->vm_page_prot = pgprot_decrypted(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.
+	 * Set vm_flags now, they should not be changed in the fault handler.
+	 * We want the same flags and page protection (decrypted above) as
+	 * io_remap_pfn_range() would set.
 	 *
 	 * VM_ALLOW_ANY_UNCACHED: The VMA flag is implemented for ARM64,
 	 * allowing KVM stage 2 device mapping attributes to use Normal-NC
@@ -2202,8 +2080,6 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev)
 	mutex_init(&vdev->ioeventfds_lock);
 	INIT_LIST_HEAD(&vdev->dummy_resources_list);
 	INIT_LIST_HEAD(&vdev->ioeventfds_list);
-	mutex_init(&vdev->vma_lock);
-	INIT_LIST_HEAD(&vdev->vma_list);
 	INIT_LIST_HEAD(&vdev->sriov_pfs_item);
 	init_rwsem(&vdev->memory_lock);
 	xa_init(&vdev->ctx);
@@ -2219,7 +2095,6 @@ void vfio_pci_core_release_dev(struct vfio_device *core_vdev)
 
 	mutex_destroy(&vdev->igate);
 	mutex_destroy(&vdev->ioeventfds_lock);
-	mutex_destroy(&vdev->vma_lock);
 	kfree(vdev->region);
 	kfree(vdev->pm_save);
 }
@@ -2497,26 +2372,15 @@ unwind:
 	return ret;
 }
 
-/*
- * We need to get memory_lock for each device, but devices can share mmap_lock,
- * therefore we need to zap and hold the vma_lock for each device, and only then
- * get each memory_lock.
- */
 static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
 				      struct vfio_pci_group_info *groups,
 				      struct iommufd_ctx *iommufd_ctx)
 {
-	struct vfio_pci_core_device *cur_mem;
-	struct vfio_pci_core_device *cur_vma;
-	struct vfio_pci_core_device *cur;
+	struct vfio_pci_core_device *vdev;
 	struct pci_dev *pdev;
-	bool is_mem = true;
 	int ret;
 
 	mutex_lock(&dev_set->lock);
-	cur_mem = list_first_entry(&dev_set->device_list,
-				   struct vfio_pci_core_device,
-				   vdev.dev_set_list);
 
 	pdev = vfio_pci_dev_set_resettable(dev_set);
 	if (!pdev) {
@@ -2533,7 +2397,7 @@ static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
 	if (ret)
 		goto err_unlock;
 
-	list_for_each_entry(cur_vma, &dev_set->device_list, vdev.dev_set_list) {
+	list_for_each_entry(vdev, &dev_set->device_list, vdev.dev_set_list) {
 		bool owned;
 
 		/*
@@ -2557,38 +2421,38 @@ static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
 		 * Otherwise, reset is not allowed.
 		 */
 		if (iommufd_ctx) {
-			int devid = vfio_iommufd_get_dev_id(&cur_vma->vdev,
+			int devid = vfio_iommufd_get_dev_id(&vdev->vdev,
 							    iommufd_ctx);
 
 			owned = (devid > 0 || devid == -ENOENT);
 		} else {
-			owned = vfio_dev_in_groups(&cur_vma->vdev, groups);
+			owned = vfio_dev_in_groups(&vdev->vdev, groups);
 		}
 
 		if (!owned) {
 			ret = -EINVAL;
-			goto err_undo;
+			break;
 		}
 
 		/*
-		 * Locking multiple devices is prone to deadlock, runaway and
-		 * unwind if we hit contention.
+		 * Take the memory write lock for each device and zap BAR
+		 * mappings to prevent the user accessing the device while in
+		 * reset.  Locking multiple devices is prone to deadlock,
+		 * runaway and unwind if we hit contention.
 		 */
-		if (!vfio_pci_zap_and_vma_lock(cur_vma, true)) {
+		if (!down_write_trylock(&vdev->memory_lock)) {
 			ret = -EBUSY;
-			goto err_undo;
+			break;
 		}
+
+		vfio_pci_zap_bars(vdev);
 	}
-	cur_vma = NULL;
 
-	list_for_each_entry(cur_mem, &dev_set->device_list, vdev.dev_set_list) {
-		if (!down_write_trylock(&cur_mem->memory_lock)) {
-			ret = -EBUSY;
-			goto err_undo;
-		}
-		mutex_unlock(&cur_mem->vma_lock);
+	if (!list_entry_is_head(vdev,
+				&dev_set->device_list, vdev.dev_set_list)) {
+		vdev = list_prev_entry(vdev, vdev.dev_set_list);
+		goto err_undo;
 	}
-	cur_mem = NULL;
 
 	/*
 	 * The pci_reset_bus() will reset all the devices in the bus.
@@ -2599,25 +2463,22 @@ static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
 	 * cause the PCI config space reset without restoring the original
 	 * state (saved locally in 'vdev->pm_save').
 	 */
-	list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list)
-		vfio_pci_set_power_state(cur, PCI_D0);
+	list_for_each_entry(vdev, &dev_set->device_list, vdev.dev_set_list)
+		vfio_pci_set_power_state(vdev, PCI_D0);
 
 	ret = pci_reset_bus(pdev);
 
+	vdev = list_last_entry(&dev_set->device_list,
+			       struct vfio_pci_core_device, vdev.dev_set_list);
+
 err_undo:
-	list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) {
-		if (cur == cur_mem)
-			is_mem = false;
-		if (cur == cur_vma)
-			break;
-		if (is_mem)
-			up_write(&cur->memory_lock);
-		else
-			mutex_unlock(&cur->vma_lock);
-	}
+	list_for_each_entry_from_reverse(vdev, &dev_set->device_list,
+					 vdev.dev_set_list)
+		up_write(&vdev->memory_lock);
+
+	list_for_each_entry(vdev, &dev_set->device_list, vdev.dev_set_list)
+		pm_runtime_put(&vdev->pdev->dev);
 
-	list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list)
-		pm_runtime_put(&cur->pdev->dev);
 err_unlock:
 	mutex_unlock(&dev_set->lock);
 	return ret;