vfio: Introduce a vfio_uninit_group_dev() API call

This pairs with vfio_init_group_dev() and allows undoing any state that is
stored in the vfio_device unrelated to registration. Add appropriately
placed calls to all the drivers.

The following patch will use this to add pre-registration state for the
device set.

Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v4-9ea22c5e6afb+1adf-vfio_reflck_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Documentation/driver-api/vfio.rst

@@ -255,11 +255,13 @@ vfio_unregister_group_dev() respectively::
 	void vfio_init_group_dev(struct vfio_device *device,
 				struct device *dev,
 				const struct vfio_device_ops *ops);
+	void vfio_uninit_group_dev(struct vfio_device *device);
 	int vfio_register_group_dev(struct vfio_device *device);
 	void vfio_unregister_group_dev(struct vfio_device *device);
 
 The driver should embed the vfio_device in its own structure and call
-vfio_init_group_dev() to pre-configure it before going to registration.
+vfio_init_group_dev() to pre-configure it before going to registration
+and call vfio_uninit_group_dev() after completing the un-registration.
 vfio_register_group_dev() indicates to the core to begin tracking the
 iommu_group of the specified dev and register the dev as owned by a VFIO bus
 driver. Once vfio_register_group_dev() returns it is possible for userspace to

drivers/vfio/fsl-mc/vfio_fsl_mc.c

@@ -627,7 +627,7 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
 
 	ret = vfio_fsl_mc_reflck_attach(vdev);
 	if (ret)
-		goto out_kfree;
+		goto out_uninit;
 
 	ret = vfio_fsl_mc_init_device(vdev);
 	if (ret)
@@ -657,7 +657,8 @@ out_device:
 	vfio_fsl_uninit_device(vdev);
 out_reflck:
 	vfio_fsl_mc_reflck_put(vdev->reflck);
-out_kfree:
+out_uninit:
+	vfio_uninit_group_dev(&vdev->vdev);
 	kfree(vdev);
 out_group_put:
 	vfio_iommu_group_put(group, dev);
@@ -675,7 +676,7 @@ static int vfio_fsl_mc_remove(struct fsl_mc_device *mc_dev)
 	dprc_remove_devices(mc_dev, NULL, 0);
 	vfio_fsl_uninit_device(vdev);
 	vfio_fsl_mc_reflck_put(vdev->reflck);
-
+	vfio_uninit_group_dev(&vdev->vdev);
 	kfree(vdev);
 	vfio_iommu_group_put(mc_dev->dev.iommu_group, dev);
 

drivers/vfio/mdev/vfio_mdev.c

@@ -120,12 +120,16 @@ static int vfio_mdev_probe(struct mdev_device *mdev)
 
 	vfio_init_group_dev(vdev, &mdev->dev, &vfio_mdev_dev_ops);
 	ret = vfio_register_group_dev(vdev);
-	if (ret) {
-		kfree(vdev);
-		return ret;
-	}
+	if (ret)
+		goto out_uninit;
+
 	dev_set_drvdata(&mdev->dev, vdev);
 	return 0;
+
+out_uninit:
+	vfio_uninit_group_dev(vdev);
+	kfree(vdev);
+	return ret;
 }
 
 static void vfio_mdev_remove(struct mdev_device *mdev)
@@ -133,6 +137,7 @@ static void vfio_mdev_remove(struct mdev_device *mdev)
 	struct vfio_device *vdev = dev_get_drvdata(&mdev->dev);
 
 	vfio_unregister_group_dev(vdev);
+	vfio_uninit_group_dev(vdev);
 	kfree(vdev);
 }
 

drivers/vfio/pci/vfio_pci.c

@@ -2022,7 +2022,7 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	ret = vfio_pci_reflck_attach(vdev);
 	if (ret)
-		goto out_free;
+		goto out_uninit;
 	ret = vfio_pci_vf_init(vdev);
 	if (ret)
 		goto out_reflck;
@@ -2059,7 +2059,8 @@ out_vf:
 	vfio_pci_vf_uninit(vdev);
 out_reflck:
 	vfio_pci_reflck_put(vdev->reflck);
-out_free:
+out_uninit:
+	vfio_uninit_group_dev(&vdev->vdev);
 	kfree(vdev->pm_save);
 	kfree(vdev);
 out_group_put:
@@ -2077,6 +2078,7 @@ static void vfio_pci_remove(struct pci_dev *pdev)
 
 	vfio_pci_vf_uninit(vdev);
 	vfio_pci_reflck_put(vdev->reflck);
+	vfio_uninit_group_dev(&vdev->vdev);
 	vfio_pci_vga_uninit(vdev);
 
 	vfio_iommu_group_put(pdev->dev.iommu_group, &pdev->dev);

drivers/vfio/platform/vfio_platform_common.c

@@ -667,7 +667,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 		ret = vfio_platform_of_probe(vdev, dev);
 
 	if (ret)
-		return ret;
+		goto out_uninit;
 
 	vdev->device = dev;
 
@@ -675,7 +675,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 	if (ret && vdev->reset_required) {
 		dev_err(dev, "No reset function found for device %s\n",
 			vdev->name);
-		return ret;
+		goto out_uninit;
 	}
 
 	group = vfio_iommu_group_get(dev);
@@ -698,6 +698,8 @@ put_iommu:
 	vfio_iommu_group_put(group, dev);
 put_reset:
 	vfio_platform_put_reset(vdev);
+out_uninit:
+	vfio_uninit_group_dev(&vdev->vdev);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
@@ -708,6 +710,7 @@ void vfio_platform_remove_common(struct vfio_platform_device *vdev)
 
 	pm_runtime_disable(vdev->device);
 	vfio_platform_put_reset(vdev);
+	vfio_uninit_group_dev(&vdev->vdev);
 	vfio_iommu_group_put(vdev->vdev.dev->iommu_group, vdev->vdev.dev);
 }
 EXPORT_SYMBOL_GPL(vfio_platform_remove_common);

drivers/vfio/vfio.c

@@ -749,6 +749,11 @@ void vfio_init_group_dev(struct vfio_device *device, struct device *dev,
 }
 EXPORT_SYMBOL_GPL(vfio_init_group_dev);
 
+void vfio_uninit_group_dev(struct vfio_device *device)
+{
+}
+EXPORT_SYMBOL_GPL(vfio_uninit_group_dev);
+
 int vfio_register_group_dev(struct vfio_device *device)
 {
 	struct vfio_device *existing_device;

include/linux/vfio.h

@@ -61,6 +61,7 @@ extern void vfio_iommu_group_put(struct iommu_group *group, struct device *dev);
 
 void vfio_init_group_dev(struct vfio_device *device, struct device *dev,
 			 const struct vfio_device_ops *ops);
+void vfio_uninit_group_dev(struct vfio_device *device);
 int vfio_register_group_dev(struct vfio_device *device);
 void vfio_unregister_group_dev(struct vfio_device *device);
 extern struct vfio_device *vfio_device_get_from_dev(struct device *dev);

samples/vfio-mdev/mbochs.c

@@ -559,6 +559,7 @@ static int mbochs_probe(struct mdev_device *mdev)
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
 err_mem:
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	kfree(mdev_state->pages);
 	kfree(mdev_state->vconfig);
 	kfree(mdev_state);
@@ -572,6 +573,7 @@ static void mbochs_remove(struct mdev_device *mdev)
 	struct mdev_state *mdev_state = dev_get_drvdata(&mdev->dev);
 
 	vfio_unregister_group_dev(&mdev_state->vdev);
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	atomic_add(mdev_state->type->mbytes, &mbochs_avail_mbytes);
 	kfree(mdev_state->pages);
 	kfree(mdev_state->vconfig);

samples/vfio-mdev/mdpy.c

@@ -235,17 +235,16 @@ static int mdpy_probe(struct mdev_device *mdev)
 
 	mdev_state->vconfig = kzalloc(MDPY_CONFIG_SPACE_SIZE, GFP_KERNEL);
 	if (mdev_state->vconfig == NULL) {
-		kfree(mdev_state);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_state;
 	}
 
 	fbsize = roundup_pow_of_two(type->width * type->height * type->bytepp);
 
 	mdev_state->memblk = vmalloc_user(fbsize);
 	if (!mdev_state->memblk) {
-		kfree(mdev_state->vconfig);
-		kfree(mdev_state);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_vconfig;
 	}
 	dev_info(dev, "%s: %s (%dx%d)\n", __func__, type->name, type->width,
 		 type->height);
@@ -260,13 +259,18 @@ static int mdpy_probe(struct mdev_device *mdev)
 	mdpy_count++;
 
 	ret = vfio_register_group_dev(&mdev_state->vdev);
-	if (ret) {
-		kfree(mdev_state->vconfig);
-		kfree(mdev_state);
-		return ret;
-	}
+	if (ret)
+		goto err_mem;
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
+err_mem:
+	vfree(mdev_state->memblk);
+err_vconfig:
+	kfree(mdev_state->vconfig);
+err_state:
+	vfio_uninit_group_dev(&mdev_state->vdev);
+	kfree(mdev_state);
+	return ret;
 }
 
 static void mdpy_remove(struct mdev_device *mdev)
@@ -278,6 +282,7 @@ static void mdpy_remove(struct mdev_device *mdev)
 	vfio_unregister_group_dev(&mdev_state->vdev);
 	vfree(mdev_state->memblk);
 	kfree(mdev_state->vconfig);
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	kfree(mdev_state);
 
 	mdpy_count--;

samples/vfio-mdev/mtty.c

@@ -718,8 +718,8 @@ static int mtty_probe(struct mdev_device *mdev)
 
 	mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL);
 	if (mdev_state == NULL) {
-		atomic_add(nr_ports, &mdev_avail_ports);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_nr_ports;
 	}
 
 	vfio_init_group_dev(&mdev_state->vdev, &mdev->dev, &mtty_dev_ops);
@@ -732,9 +732,8 @@ static int mtty_probe(struct mdev_device *mdev)
 	mdev_state->vconfig = kzalloc(MTTY_CONFIG_SPACE_SIZE, GFP_KERNEL);
 
 	if (mdev_state->vconfig == NULL) {
-		kfree(mdev_state);
-		atomic_add(nr_ports, &mdev_avail_ports);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_state;
 	}
 
 	mutex_init(&mdev_state->ops_lock);
@@ -743,14 +742,19 @@ static int mtty_probe(struct mdev_device *mdev)
 	mtty_create_config_space(mdev_state);
 
 	ret = vfio_register_group_dev(&mdev_state->vdev);
-	if (ret) {
-		kfree(mdev_state);
-		atomic_add(nr_ports, &mdev_avail_ports);
-		return ret;
-	}
-
+	if (ret)
+		goto err_vconfig;
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
+
+err_vconfig:
+	kfree(mdev_state->vconfig);
+err_state:
+	vfio_uninit_group_dev(&mdev_state->vdev);
+	kfree(mdev_state);
+err_nr_ports:
+	atomic_add(nr_ports, &mdev_avail_ports);
+	return ret;
 }
 
 static void mtty_remove(struct mdev_device *mdev)
@@ -761,6 +765,7 @@ static void mtty_remove(struct mdev_device *mdev)
 	vfio_unregister_group_dev(&mdev_state->vdev);
 
 	kfree(mdev_state->vconfig);
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	kfree(mdev_state);
 	atomic_add(nr_ports, &mdev_avail_ports);
 }