1 files changed, 89 insertions, 124 deletions

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 0147f04c91b2..a4f44ea52fa3 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -223,9 +223,11 @@ no_mmap:
 	}
 }
 
+struct vfio_pci_group_info;
 static bool vfio_pci_dev_set_try_reset(struct vfio_device_set *dev_set);
 static void vfio_pci_disable(struct vfio_pci_device *vdev);
-static int vfio_pci_try_zap_and_vma_lock_cb(struct pci_dev *pdev, void *data);
+static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
+				      struct vfio_pci_group_info *groups);
 
 /*
  * INTx masking requires the ability to disable INTx signaling via PCI_COMMAND
@@ -643,37 +645,11 @@ static int vfio_pci_fill_devs(struct pci_dev *pdev, void *data)
 	return 0;
 }
 
-struct vfio_pci_group_entry {
-	struct vfio_group *group;
-	int id;
-};
-
 struct vfio_pci_group_info {
 	int count;
-	struct vfio_pci_group_entry *groups;
+	struct vfio_group **groups;
 };
 
-static int vfio_pci_validate_devs(struct pci_dev *pdev, void *data)
-{
-	struct vfio_pci_group_info *info = data;
-	struct iommu_group *group;
-	int id, i;
-
-	group = iommu_group_get(&pdev->dev);
-	if (!group)
-		return -EPERM;
-
-	id = iommu_group_id(group);
-
-	for (i = 0; i < info->count; i++)
-		if (info->groups[i].id == id)
-			break;
-
-	iommu_group_put(group);
-
-	return (i == info->count) ? -EINVAL : 0;
-}
-
 static bool vfio_pci_dev_below_slot(struct pci_dev *pdev, struct pci_slot *slot)
 {
 	for (; pdev; pdev = pdev->bus->self)
@@ -751,12 +727,6 @@ int vfio_pci_register_dev_region(struct vfio_pci_device *vdev,
 	return 0;
 }
 
-struct vfio_devices {
-	struct vfio_pci_device **devices;
-	int cur_index;
-	int max_index;
-};
-
 static long vfio_pci_ioctl(struct vfio_device *core_vdev,
 			   unsigned int cmd, unsigned long arg)
 {
@@ -1125,11 +1095,10 @@ reset_info_exit:
 	} else if (cmd == VFIO_DEVICE_PCI_HOT_RESET) {
 		struct vfio_pci_hot_reset hdr;
 		int32_t *group_fds;
-		struct vfio_pci_group_entry *groups;
+		struct vfio_group **groups;
 		struct vfio_pci_group_info info;
-		struct vfio_devices devs = { .cur_index = 0 };
 		bool slot = false;
-		int i, group_idx, mem_idx = 0, count = 0, ret = 0;
+		int group_idx, count = 0, ret = 0;
 
 		minsz = offsetofend(struct vfio_pci_hot_reset, count);
 
@@ -1196,9 +1165,7 @@ reset_info_exit:
 				break;
 			}
 
-			groups[group_idx].group = group;
-			groups[group_idx].id =
-					vfio_external_user_iommu_id(group);
+			groups[group_idx] = group;
 		}
 
 		kfree(group_fds);
@@ -1210,64 +1177,11 @@ reset_info_exit:
 		info.count = hdr.count;
 		info.groups = groups;
 
-		/*
-		 * Test whether all the affected devices are contained
-		 * by the set of groups provided by the user.
-		 */
-		ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
-						    vfio_pci_validate_devs,
-						    &info, slot);
-		if (ret)
-			goto hot_reset_release;
-
-		devs.max_index = count;
-		devs.devices = kcalloc(count, sizeof(struct vfio_device *),
-				       GFP_KERNEL);
-		if (!devs.devices) {
-			ret = -ENOMEM;
-			goto hot_reset_release;
-		}
-
-		/*
-		 * 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.
-		 */
-		ret = vfio_pci_for_each_slot_or_bus(vdev->pdev,
-					    vfio_pci_try_zap_and_vma_lock_cb,
-					    &devs, slot);
-		if (ret)
-			goto hot_reset_release;
-
-		for (; mem_idx < devs.cur_index; mem_idx++) {
-			struct vfio_pci_device *tmp = devs.devices[mem_idx];
-
-			ret = down_write_trylock(&tmp->memory_lock);
-			if (!ret) {
-				ret = -EBUSY;
-				goto hot_reset_release;
-			}
-			mutex_unlock(&tmp->vma_lock);
-		}
-
-		/* User has access, do the reset */
-		ret = pci_reset_bus(vdev->pdev);
+		ret = vfio_pci_dev_set_hot_reset(vdev->vdev.dev_set, &info);
 
 hot_reset_release:
-		for (i = 0; i < devs.cur_index; i++) {
-			struct vfio_pci_device *tmp = devs.devices[i];
-
-			if (i < mem_idx)
-				up_write(&tmp->memory_lock);
-			else
-				mutex_unlock(&tmp->vma_lock);
-			vfio_device_put(&tmp->vdev);
-		}
-		kfree(devs.devices);
-
 		for (group_idx--; group_idx >= 0; group_idx--)
-			vfio_group_put_external_user(groups[group_idx].group);
+			vfio_group_put_external_user(groups[group_idx]);
 
 		kfree(groups);
 		return ret;
@@ -2146,37 +2060,15 @@ static struct pci_driver vfio_pci_driver = {
 	.err_handler		= &vfio_err_handlers,
 };
 
-static int vfio_pci_try_zap_and_vma_lock_cb(struct pci_dev *pdev, void *data)
+static bool vfio_dev_in_groups(struct vfio_pci_device *vdev,
+			       struct vfio_pci_group_info *groups)
 {
-	struct vfio_devices *devs = data;
-	struct vfio_device *device;
-	struct vfio_pci_device *vdev;
-
-	if (devs->cur_index == devs->max_index)
-		return -ENOSPC;
-
-	device = vfio_device_get_from_dev(&pdev->dev);
-	if (!device)
-		return -EINVAL;
-
-	if (pci_dev_driver(pdev) != &vfio_pci_driver) {
-		vfio_device_put(device);
-		return -EBUSY;
-	}
-
-	vdev = container_of(device, struct vfio_pci_device, vdev);
+	unsigned int i;
 
-	/*
-	 * Locking multiple devices is prone to deadlock, runaway and
-	 * unwind if we hit contention.
-	 */
-	if (!vfio_pci_zap_and_vma_lock(vdev, true)) {
-		vfio_device_put(device);
-		return -EBUSY;
-	}
-
-	devs->devices[devs->cur_index++] = vdev;
-	return 0;
+	for (i = 0; i < groups->count; i++)
+		if (groups->groups[i] == vdev->vdev.group)
+			return true;
+	return false;
 }
 
 static int vfio_pci_is_device_in_set(struct pci_dev *pdev, void *data)
@@ -2226,6 +2118,79 @@ vfio_pci_dev_set_resettable(struct vfio_device_set *dev_set)
 	return pdev;
 }
 
+/*
+ * 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 vfio_pci_device *cur_mem;
+	struct vfio_pci_device *cur_vma;
+	struct vfio_pci_device *cur;
+	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_device, vdev.dev_set_list);
+
+	pdev = vfio_pci_dev_set_resettable(dev_set);
+	if (!pdev) {
+		ret = -EINVAL;
+		goto err_unlock;
+	}
+
+	list_for_each_entry(cur_vma, &dev_set->device_list, vdev.dev_set_list) {
+		/*
+		 * Test whether all the affected devices are contained by the
+		 * set of groups provided by the user.
+		 */
+		if (!vfio_dev_in_groups(cur_vma, groups)) {
+			ret = -EINVAL;
+			goto err_undo;
+		}
+
+		/*
+		 * Locking multiple devices is prone to deadlock, runaway and
+		 * unwind if we hit contention.
+		 */
+		if (!vfio_pci_zap_and_vma_lock(cur_vma, true)) {
+			ret = -EBUSY;
+			goto err_undo;
+		}
+	}
+	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);
+	}
+	cur_mem = NULL;
+
+	ret = pci_reset_bus(pdev);
+
+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);
+	}
+err_unlock:
+	mutex_unlock(&dev_set->lock);
+	return ret;
+}
+
 static bool vfio_pci_dev_set_needs_reset(struct vfio_device_set *dev_set)
 {
 	struct vfio_pci_device *cur;