[PATCH v4 0/2] Remove vfio_device_get_from_dev()

[PATCH v4 0/2] Remove vfio_device_get_from_dev()

[Jason Gunthorpe]

Use drvdata instead of searching to find the struct vfio_device for the
pci_driver callbacks.

This applies on top of the gvt series and at least rc3 - there are no
conflicts with the mdev vfio_group series, or the iommu series.

v4:
 - Put back missing rebase hunk for vfio_group_get_from_dev()
 - Move the WARN_ON to vfio_pci_core_register_device() and move the
   dev_set_drvdata() to match
v3: https://lore.kernel.org/r/0-v3-4adf6c1b8e7c+170-vfio_get_from_dev_jgg@nvidia.com
 - Directly access the drvdata from vfio_pci_core by making drvdata always
   point to the core struct. This will help later patches adding PM
   callbacks as well.
v2: https://lore.kernel.org/r/0-v2-0f36bcf6ec1e+64d-vfio_get_from_dev_jgg@nvidia.com
 - Rebase on the vfio_mdev_no_group branch
 - Delete vfio_group_get_from_dev() as well due to the rebase
v1: https://lore.kernel.org/r/0-v1-7f2292e6b2ba+44839-vfio_get_from_dev_jgg@nvidia.com

Jason Gunthorpe (2):
  vfio/pci: Have all VFIO PCI drivers store the vfio_pci_core_device in
    drvdata
  vfio/pci: Remove vfio_device_get_from_dev()

 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 15 +++++--
 drivers/vfio/pci/mlx5/main.c                  | 15 +++++--
 drivers/vfio/pci/vfio_pci.c                   |  6 ++-
 drivers/vfio/pci/vfio_pci_core.c              | 36 +++++-----------
 drivers/vfio/vfio.c                           | 41 +------------------
 include/linux/vfio.h                          |  2 -
 include/linux/vfio_pci_core.h                 |  3 +-
 7 files changed, 39 insertions(+), 79 deletions(-)


base-commit: 21ce7c292b5684f930cc63f3841ec692bbd6c10a
-- 
2.36.0

[PATCH v4 1/2] vfio/pci: Have all VFIO PCI drivers store the vfio_pci_core_device in drvdata

[Jason Gunthorpe]

Having a consistent pointer in the drvdata will allow the next patch to
make use of the drvdata from some of the core code helpers.

Use a WARN_ON inside vfio_pci_core_enable() to detect drivers that miss
this.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 15 +++++++++++----
 drivers/vfio/pci/mlx5/main.c                   | 15 +++++++++++----
 drivers/vfio/pci/vfio_pci.c                    |  2 +-
 drivers/vfio/pci/vfio_pci_core.c               |  4 ++++
 4 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index 767b5d47631a49..e92376837b29e6 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -337,6 +337,14 @@ static int vf_qm_cache_wb(struct hisi_qm *qm)
 	return 0;
 }
 
+static struct hisi_acc_vf_core_device *hssi_acc_drvdata(struct pci_dev *pdev)
+{
+	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
+
+	return container_of(core_device, struct hisi_acc_vf_core_device,
+			    core_device);
+}
+
 static void vf_qm_fun_reset(struct hisi_acc_vf_core_device *hisi_acc_vdev,
 			    struct hisi_qm *qm)
 {
@@ -962,7 +970,7 @@ hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
 
 static void hisi_acc_vf_pci_aer_reset_done(struct pci_dev *pdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = dev_get_drvdata(&pdev->dev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hssi_acc_drvdata(pdev);
 
 	if (hisi_acc_vdev->core_device.vdev.migration_flags !=
 				VFIO_MIGRATION_STOP_COPY)
@@ -1274,11 +1282,10 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
 					  &hisi_acc_vfio_pci_ops);
 	}
 
+	dev_set_drvdata(&pdev->dev, &hisi_acc_vdev->core_device);
 	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
 	if (ret)
 		goto out_free;
-
-	dev_set_drvdata(&pdev->dev, hisi_acc_vdev);
 	return 0;
 
 out_free:
@@ -1289,7 +1296,7 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
 
 static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = dev_get_drvdata(&pdev->dev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hssi_acc_drvdata(pdev);
 
 	vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);
 	vfio_pci_core_uninit_device(&hisi_acc_vdev->core_device);
diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
index bbec5d288fee97..9f59f5807b8ab1 100644
--- a/drivers/vfio/pci/mlx5/main.c
+++ b/drivers/vfio/pci/mlx5/main.c
@@ -39,6 +39,14 @@ struct mlx5vf_pci_core_device {
 	struct mlx5_vf_migration_file *saving_migf;
 };
 
+static struct mlx5vf_pci_core_device *mlx5vf_drvdata(struct pci_dev *pdev)
+{
+	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
+
+	return container_of(core_device, struct mlx5vf_pci_core_device,
+			    core_device);
+}
+
 static struct page *
 mlx5vf_get_migration_page(struct mlx5_vf_migration_file *migf,
 			  unsigned long offset)
@@ -505,7 +513,7 @@ static int mlx5vf_pci_get_device_state(struct vfio_device *vdev,
 
 static void mlx5vf_pci_aer_reset_done(struct pci_dev *pdev)
 {
-	struct mlx5vf_pci_core_device *mvdev = dev_get_drvdata(&pdev->dev);
+	struct mlx5vf_pci_core_device *mvdev = mlx5vf_drvdata(pdev);
 
 	if (!mvdev->migrate_cap)
 		return;
@@ -614,11 +622,10 @@ static int mlx5vf_pci_probe(struct pci_dev *pdev,
 		}
 	}
 
+	dev_set_drvdata(&pdev->dev, &mvdev->core_device);
 	ret = vfio_pci_core_register_device(&mvdev->core_device);
 	if (ret)
 		goto out_free;
-
-	dev_set_drvdata(&pdev->dev, mvdev);
 	return 0;
 
 out_free:
@@ -629,7 +636,7 @@ static int mlx5vf_pci_probe(struct pci_dev *pdev,
 
 static void mlx5vf_pci_remove(struct pci_dev *pdev)
 {
-	struct mlx5vf_pci_core_device *mvdev = dev_get_drvdata(&pdev->dev);
+	struct mlx5vf_pci_core_device *mvdev = mlx5vf_drvdata(pdev);
 
 	vfio_pci_core_unregister_device(&mvdev->core_device);
 	vfio_pci_core_uninit_device(&mvdev->core_device);
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 58839206d1ca7f..e34db35b8d61a1 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -151,10 +151,10 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		return -ENOMEM;
 	vfio_pci_core_init_device(vdev, pdev, &vfio_pci_ops);
 
+	dev_set_drvdata(&pdev->dev, vdev);
 	ret = vfio_pci_core_register_device(vdev);
 	if (ret)
 		goto out_free;
-	dev_set_drvdata(&pdev->dev, vdev);
 	return 0;
 
 out_free:
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 06b6f3594a1316..65587fd5c021bb 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1821,6 +1821,10 @@ int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
 	struct pci_dev *pdev = vdev->pdev;
 	int ret;
 
+	/* Drivers must set the vfio_pci_core_device to their drvdata */
+	if (WARN_ON(vdev != dev_get_drvdata(&vdev->pdev->dev)))
+		return -EINVAL;
+
 	if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL)
 		return -EINVAL;
 
-- 
2.36.0

Re: [PATCH v4 1/2] vfio/pci: Have all VFIO PCI drivers store the vfio_pci_core_device in drvdata

[Alex Williamson]

On Thu,  5 May 2022 20:21:39 -0300
Jason Gunthorpe <jgg@nvidia.com> wrote:

> Having a consistent pointer in the drvdata will allow the next patch to
> make use of the drvdata from some of the core code helpers.
> 
> Use a WARN_ON inside vfio_pci_core_enable() to detect drivers that miss
> this.

Stale comment, I'll

s/vfio_pci_core_enable/vfio_pci_core_register_device/

on commit.  Looks ok otherwise.  Thanks,

Alex

> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 15 +++++++++++----
>  drivers/vfio/pci/mlx5/main.c                   | 15 +++++++++++----
>  drivers/vfio/pci/vfio_pci.c                    |  2 +-
>  drivers/vfio/pci/vfio_pci_core.c               |  4 ++++
>  4 files changed, 27 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 767b5d47631a49..e92376837b29e6 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -337,6 +337,14 @@ static int vf_qm_cache_wb(struct hisi_qm *qm)
>  	return 0;
>  }
>  
> +static struct hisi_acc_vf_core_device *hssi_acc_drvdata(struct pci_dev *pdev)
> +{
> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
> +
> +	return container_of(core_device, struct hisi_acc_vf_core_device,
> +			    core_device);
> +}
> +
>  static void vf_qm_fun_reset(struct hisi_acc_vf_core_device *hisi_acc_vdev,
>  			    struct hisi_qm *qm)
>  {
> @@ -962,7 +970,7 @@ hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
>  
>  static void hisi_acc_vf_pci_aer_reset_done(struct pci_dev *pdev)
>  {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev = dev_get_drvdata(&pdev->dev);
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hssi_acc_drvdata(pdev);
>  
>  	if (hisi_acc_vdev->core_device.vdev.migration_flags !=
>  				VFIO_MIGRATION_STOP_COPY)
> @@ -1274,11 +1282,10 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>  					  &hisi_acc_vfio_pci_ops);
>  	}
>  
> +	dev_set_drvdata(&pdev->dev, &hisi_acc_vdev->core_device);
>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>  	if (ret)
>  		goto out_free;
> -
> -	dev_set_drvdata(&pdev->dev, hisi_acc_vdev);
>  	return 0;
>  
>  out_free:
> @@ -1289,7 +1296,7 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>  
>  static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev)
>  {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev = dev_get_drvdata(&pdev->dev);
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hssi_acc_drvdata(pdev);
>  
>  	vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);
>  	vfio_pci_core_uninit_device(&hisi_acc_vdev->core_device);
> diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
> index bbec5d288fee97..9f59f5807b8ab1 100644
> --- a/drivers/vfio/pci/mlx5/main.c
> +++ b/drivers/vfio/pci/mlx5/main.c
> @@ -39,6 +39,14 @@ struct mlx5vf_pci_core_device {
>  	struct mlx5_vf_migration_file *saving_migf;
>  };
>  
> +static struct mlx5vf_pci_core_device *mlx5vf_drvdata(struct pci_dev *pdev)
> +{
> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
> +
> +	return container_of(core_device, struct mlx5vf_pci_core_device,
> +			    core_device);
> +}
> +
>  static struct page *
>  mlx5vf_get_migration_page(struct mlx5_vf_migration_file *migf,
>  			  unsigned long offset)
> @@ -505,7 +513,7 @@ static int mlx5vf_pci_get_device_state(struct vfio_device *vdev,
>  
>  static void mlx5vf_pci_aer_reset_done(struct pci_dev *pdev)
>  {
> -	struct mlx5vf_pci_core_device *mvdev = dev_get_drvdata(&pdev->dev);
> +	struct mlx5vf_pci_core_device *mvdev = mlx5vf_drvdata(pdev);
>  
>  	if (!mvdev->migrate_cap)
>  		return;
> @@ -614,11 +622,10 @@ static int mlx5vf_pci_probe(struct pci_dev *pdev,
>  		}
>  	}
>  
> +	dev_set_drvdata(&pdev->dev, &mvdev->core_device);
>  	ret = vfio_pci_core_register_device(&mvdev->core_device);
>  	if (ret)
>  		goto out_free;
> -
> -	dev_set_drvdata(&pdev->dev, mvdev);
>  	return 0;
>  
>  out_free:
> @@ -629,7 +636,7 @@ static int mlx5vf_pci_probe(struct pci_dev *pdev,
>  
>  static void mlx5vf_pci_remove(struct pci_dev *pdev)
>  {
> -	struct mlx5vf_pci_core_device *mvdev = dev_get_drvdata(&pdev->dev);
> +	struct mlx5vf_pci_core_device *mvdev = mlx5vf_drvdata(pdev);
>  
>  	vfio_pci_core_unregister_device(&mvdev->core_device);
>  	vfio_pci_core_uninit_device(&mvdev->core_device);
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index 58839206d1ca7f..e34db35b8d61a1 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -151,10 +151,10 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  		return -ENOMEM;
>  	vfio_pci_core_init_device(vdev, pdev, &vfio_pci_ops);
>  
> +	dev_set_drvdata(&pdev->dev, vdev);
>  	ret = vfio_pci_core_register_device(vdev);
>  	if (ret)
>  		goto out_free;
> -	dev_set_drvdata(&pdev->dev, vdev);
>  	return 0;
>  
>  out_free:
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 06b6f3594a1316..65587fd5c021bb 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -1821,6 +1821,10 @@ int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
>  	struct pci_dev *pdev = vdev->pdev;
>  	int ret;
>  
> +	/* Drivers must set the vfio_pci_core_device to their drvdata */
> +	if (WARN_ON(vdev != dev_get_drvdata(&vdev->pdev->dev)))
> +		return -EINVAL;
> +
>  	if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL)
>  		return -EINVAL;
>  

Re: [PATCH v4 1/2] vfio/pci: Have all VFIO PCI drivers store the vfio_pci_core_device in drvdata

[Jason Gunthorpe]

On Fri, May 06, 2022 at 09:42:53AM -0600, Alex Williamson wrote:
> On Thu,  5 May 2022 20:21:39 -0300
> Jason Gunthorpe <jgg@nvidia.com> wrote:
> 
> > Having a consistent pointer in the drvdata will allow the next patch to
> > make use of the drvdata from some of the core code helpers.
> > 
> > Use a WARN_ON inside vfio_pci_core_enable() to detect drivers that miss
> > this.
> 
> Stale comment, I'll
> 
> s/vfio_pci_core_enable/vfio_pci_core_register_device/
> 
> on commit.  Looks ok otherwise.  Thanks,

Yes, thanks

Jason

Re: [PATCH v4 1/2] vfio/pci: Have all VFIO PCI drivers store the vfio_pci_core_device in drvdata

[Abhishek Sahu]

On 5/6/2022 4:51 AM, Jason Gunthorpe wrote:
> Having a consistent pointer in the drvdata will allow the next patch to
> make use of the drvdata from some of the core code helpers.
> 
> Use a WARN_ON inside vfio_pci_core_enable() to detect drivers that miss
> this.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 15 +++++++++++----
>  drivers/vfio/pci/mlx5/main.c                   | 15 +++++++++++----
>  drivers/vfio/pci/vfio_pci.c                    |  2 +-
>  drivers/vfio/pci/vfio_pci_core.c               |  4 ++++
>  4 files changed, 27 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 767b5d47631a49..e92376837b29e6 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -337,6 +337,14 @@ static int vf_qm_cache_wb(struct hisi_qm *qm)
>  	return 0;
>  }
>  
> +static struct hisi_acc_vf_core_device *hssi_acc_drvdata(struct pci_dev *pdev)
> +{
> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
> +
> +	return container_of(core_device, struct hisi_acc_vf_core_device,
> +			    core_device);
> +}
> +
>  static void vf_qm_fun_reset(struct hisi_acc_vf_core_device *hisi_acc_vdev,
>  			    struct hisi_qm *qm)
>  {
> @@ -962,7 +970,7 @@ hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
>  
>  static void hisi_acc_vf_pci_aer_reset_done(struct pci_dev *pdev)
>  {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev = dev_get_drvdata(&pdev->dev);
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hssi_acc_drvdata(pdev);
>  
>  	if (hisi_acc_vdev->core_device.vdev.migration_flags !=
>  				VFIO_MIGRATION_STOP_COPY)
> @@ -1274,11 +1282,10 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>  					  &hisi_acc_vfio_pci_ops);
>  	}
>  
> +	dev_set_drvdata(&pdev->dev, &hisi_acc_vdev->core_device);
>  	ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device);
>  	if (ret)
>  		goto out_free;
> -
> -	dev_set_drvdata(&pdev->dev, hisi_acc_vdev);
>  	return 0;
>  
>  out_free:
> @@ -1289,7 +1296,7 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device
>  
>  static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev)
>  {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev = dev_get_drvdata(&pdev->dev);
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev = hssi_acc_drvdata(pdev);
>  
>  	vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device);
>  	vfio_pci_core_uninit_device(&hisi_acc_vdev->core_device);
> diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
> index bbec5d288fee97..9f59f5807b8ab1 100644
> --- a/drivers/vfio/pci/mlx5/main.c
> +++ b/drivers/vfio/pci/mlx5/main.c
> @@ -39,6 +39,14 @@ struct mlx5vf_pci_core_device {
>  	struct mlx5_vf_migration_file *saving_migf;
>  };
>  
> +static struct mlx5vf_pci_core_device *mlx5vf_drvdata(struct pci_dev *pdev)
> +{
> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
> +
> +	return container_of(core_device, struct mlx5vf_pci_core_device,
> +			    core_device);
> +}
> +
>  static struct page *
>  mlx5vf_get_migration_page(struct mlx5_vf_migration_file *migf,
>  			  unsigned long offset)
> @@ -505,7 +513,7 @@ static int mlx5vf_pci_get_device_state(struct vfio_device *vdev,
>  
>  static void mlx5vf_pci_aer_reset_done(struct pci_dev *pdev)
>  {
> -	struct mlx5vf_pci_core_device *mvdev = dev_get_drvdata(&pdev->dev);
> +	struct mlx5vf_pci_core_device *mvdev = mlx5vf_drvdata(pdev);
>  
>  	if (!mvdev->migrate_cap)
>  		return;
> @@ -614,11 +622,10 @@ static int mlx5vf_pci_probe(struct pci_dev *pdev,
>  		}
>  	}
>  
> +	dev_set_drvdata(&pdev->dev, &mvdev->core_device);
>  	ret = vfio_pci_core_register_device(&mvdev->core_device);
>  	if (ret)
>  		goto out_free;
> -
> -	dev_set_drvdata(&pdev->dev, mvdev);
>  	return 0;
>  
>  out_free:
> @@ -629,7 +636,7 @@ static int mlx5vf_pci_probe(struct pci_dev *pdev,
>  
>  static void mlx5vf_pci_remove(struct pci_dev *pdev)
>  {
> -	struct mlx5vf_pci_core_device *mvdev = dev_get_drvdata(&pdev->dev);
> +	struct mlx5vf_pci_core_device *mvdev = mlx5vf_drvdata(pdev);
>  
>  	vfio_pci_core_unregister_device(&mvdev->core_device);
>  	vfio_pci_core_uninit_device(&mvdev->core_device);
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index 58839206d1ca7f..e34db35b8d61a1 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -151,10 +151,10 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  		return -ENOMEM;
>  	vfio_pci_core_init_device(vdev, pdev, &vfio_pci_ops);
>  
> +	dev_set_drvdata(&pdev->dev, vdev);
>  	ret = vfio_pci_core_register_device(vdev);
>  	if (ret)
>  		goto out_free;
> -	dev_set_drvdata(&pdev->dev, vdev);
>  	return 0;
>  
>  out_free:
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 06b6f3594a1316..65587fd5c021bb 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -1821,6 +1821,10 @@ int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
>  	struct pci_dev *pdev = vdev->pdev;
>  	int ret;
>  
> +	/* Drivers must set the vfio_pci_core_device to their drvdata */
> +	if (WARN_ON(vdev != dev_get_drvdata(&vdev->pdev->dev)))
> +		return -EINVAL;
> +
>  	if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL)
>  		return -EINVAL;
>  

 Thanks Jason.
 I have applied this patch locally and confirmed that my power
 management changes works fine without my dev_set_drvdata() patch.

 Regards,
 Abhishek

[PATCH v4 2/2] vfio/pci: Remove vfio_device_get_from_dev()

[Jason Gunthorpe]

The last user of this function is in PCI callbacks that want to convert
their struct pci_dev to a vfio_device. Instead of searching use the
vfio_device available trivially through the drvdata.

When a callback in the device_driver is called, the caller must hold the
device_lock() on dev. The purpose of the device_lock is to prevent
remove() from being called (see __device_release_driver), and allow the
driver to safely interact with its drvdata without races.

The PCI core correctly follows this and holds the device_lock() when
calling error_detected (see report_error_detected) and
sriov_configure (see sriov_numvfs_store).

Further, since the drvdata holds a positive refcount on the vfio_device
any access of the drvdata, under the device_lock(), from a driver callback
needs no further protection or refcounting.

Thus the remark in the vfio_device_get_from_dev() comment does not apply
here, VFIO PCI drivers all call vfio_unregister_group_dev() from their
remove callbacks under the device_lock() and cannot race with the
remaining callers.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/vfio/pci/vfio_pci.c      |  4 +++-
 drivers/vfio/pci/vfio_pci_core.c | 32 +++++--------------------
 drivers/vfio/vfio.c              | 41 +-------------------------------
 include/linux/vfio.h             |  2 --
 include/linux/vfio_pci_core.h    |  3 ++-
 5 files changed, 12 insertions(+), 70 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index e34db35b8d61a1..4d1a97415a27bf 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -174,10 +174,12 @@ static void vfio_pci_remove(struct pci_dev *pdev)
 
 static int vfio_pci_sriov_configure(struct pci_dev *pdev, int nr_virtfn)
 {
+	struct vfio_pci_core_device *vdev = dev_get_drvdata(&pdev->dev);
+
 	if (!enable_sriov)
 		return -ENOENT;
 
-	return vfio_pci_core_sriov_configure(pdev, nr_virtfn);
+	return vfio_pci_core_sriov_configure(vdev, nr_virtfn);
 }
 
 static const struct pci_device_id vfio_pci_table[] = {
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 65587fd5c021bb..100ab98c7ff021 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1894,9 +1894,7 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_register_device);
 
 void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev)
 {
-	struct pci_dev *pdev = vdev->pdev;
-
-	vfio_pci_core_sriov_configure(pdev, 0);
+	vfio_pci_core_sriov_configure(vdev, 0);
 
 	vfio_unregister_group_dev(&vdev->vdev);
 
@@ -1911,14 +1909,7 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_unregister_device);
 pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
 						pci_channel_state_t state)
 {
-	struct vfio_pci_core_device *vdev;
-	struct vfio_device *device;
-
-	device = vfio_device_get_from_dev(&pdev->dev);
-	if (device == NULL)
-		return PCI_ERS_RESULT_DISCONNECT;
-
-	vdev = container_of(device, struct vfio_pci_core_device, vdev);
+	struct vfio_pci_core_device *vdev = dev_get_drvdata(&pdev->dev);
 
 	mutex_lock(&vdev->igate);
 
@@ -1927,26 +1918,18 @@ pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
 
 	mutex_unlock(&vdev->igate);
 
-	vfio_device_put(device);
-
 	return PCI_ERS_RESULT_CAN_RECOVER;
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_aer_err_detected);
 
-int vfio_pci_core_sriov_configure(struct pci_dev *pdev, int nr_virtfn)
+int vfio_pci_core_sriov_configure(struct vfio_pci_core_device *vdev,
+				  int nr_virtfn)
 {
-	struct vfio_pci_core_device *vdev;
-	struct vfio_device *device;
+	struct pci_dev *pdev = vdev->pdev;
 	int ret = 0;
 
 	device_lock_assert(&pdev->dev);
 
-	device = vfio_device_get_from_dev(&pdev->dev);
-	if (!device)
-		return -ENODEV;
-
-	vdev = container_of(device, struct vfio_pci_core_device, vdev);
-
 	if (nr_virtfn) {
 		mutex_lock(&vfio_pci_sriov_pfs_mutex);
 		/*
@@ -1964,8 +1947,7 @@ int vfio_pci_core_sriov_configure(struct pci_dev *pdev, int nr_virtfn)
 		ret = pci_enable_sriov(pdev, nr_virtfn);
 		if (ret)
 			goto out_del;
-		ret = nr_virtfn;
-		goto out_put;
+		return nr_virtfn;
 	}
 
 	pci_disable_sriov(pdev);
@@ -1975,8 +1957,6 @@ int vfio_pci_core_sriov_configure(struct pci_dev *pdev, int nr_virtfn)
 	list_del_init(&vdev->sriov_pfs_item);
 out_unlock:
 	mutex_unlock(&vfio_pci_sriov_pfs_mutex);
-out_put:
-	vfio_device_put(device);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_sriov_configure);
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index f7d1898129ad1c..fcff23fd256a67 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -444,31 +444,15 @@ static void vfio_group_get(struct vfio_group *group)
 	refcount_inc(&group->users);
 }
 
-static struct vfio_group *vfio_group_get_from_dev(struct device *dev)
-{
-	struct iommu_group *iommu_group;
-	struct vfio_group *group;
-
-	iommu_group = iommu_group_get(dev);
-	if (!iommu_group)
-		return NULL;
-
-	group = vfio_group_get_from_iommu(iommu_group);
-	iommu_group_put(iommu_group);
-
-	return group;
-}
-
 /*
  * Device objects - create, release, get, put, search
  */
 /* Device reference always implies a group reference */
-void vfio_device_put(struct vfio_device *device)
+static void vfio_device_put(struct vfio_device *device)
 {
 	if (refcount_dec_and_test(&device->refcount))
 		complete(&device->comp);
 }
-EXPORT_SYMBOL_GPL(vfio_device_put);
 
 static bool vfio_device_try_get(struct vfio_device *device)
 {
@@ -633,29 +617,6 @@ int vfio_register_emulated_iommu_dev(struct vfio_device *device)
 }
 EXPORT_SYMBOL_GPL(vfio_register_emulated_iommu_dev);
 
-/*
- * Get a reference to the vfio_device for a device.  Even if the
- * caller thinks they own the device, they could be racing with a
- * release call path, so we can't trust drvdata for the shortcut.
- * Go the long way around, from the iommu_group to the vfio_group
- * to the vfio_device.
- */
-struct vfio_device *vfio_device_get_from_dev(struct device *dev)
-{
-	struct vfio_group *group;
-	struct vfio_device *device;
-
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return NULL;
-
-	device = vfio_group_get_device(group, dev);
-	vfio_group_put(group);
-
-	return device;
-}
-EXPORT_SYMBOL_GPL(vfio_device_get_from_dev);
-
 static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group,
 						     char *buf)
 {
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 9a9981c2622896..de8dd31b0639b0 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -125,8 +125,6 @@ void vfio_uninit_group_dev(struct vfio_device *device);
 int vfio_register_group_dev(struct vfio_device *device);
 int vfio_register_emulated_iommu_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);
-extern void vfio_device_put(struct vfio_device *device);
 
 int vfio_assign_device_set(struct vfio_device *device, void *set_id);
 
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index 48f2dd3c568c83..23c176d4b073f1 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -227,8 +227,9 @@ void vfio_pci_core_init_device(struct vfio_pci_core_device *vdev,
 int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev);
 void vfio_pci_core_uninit_device(struct vfio_pci_core_device *vdev);
 void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev);
-int vfio_pci_core_sriov_configure(struct pci_dev *pdev, int nr_virtfn);
 extern const struct pci_error_handlers vfio_pci_core_err_handlers;
+int vfio_pci_core_sriov_configure(struct vfio_pci_core_device *vdev,
+				  int nr_virtfn);
 long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
 		unsigned long arg);
 int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags,
-- 
2.36.0

Re: [PATCH v4 0/2] Remove vfio_device_get_from_dev()

[Alex Williamson]

On Thu,  5 May 2022 20:21:38 -0300
Jason Gunthorpe <jgg@nvidia.com> wrote:

> Use drvdata instead of searching to find the struct vfio_device for the
> pci_driver callbacks.
> 
> This applies on top of the gvt series and at least rc3 - there are no
> conflicts with the mdev vfio_group series, or the iommu series.
> 
> v4:
>  - Put back missing rebase hunk for vfio_group_get_from_dev()
>  - Move the WARN_ON to vfio_pci_core_register_device() and move the
>    dev_set_drvdata() to match
> v3: https://lore.kernel.org/r/0-v3-4adf6c1b8e7c+170-vfio_get_from_dev_jgg@nvidia.com
>  - Directly access the drvdata from vfio_pci_core by making drvdata always
>    point to the core struct. This will help later patches adding PM
>    callbacks as well.
> v2: https://lore.kernel.org/r/0-v2-0f36bcf6ec1e+64d-vfio_get_from_dev_jgg@nvidia.com
>  - Rebase on the vfio_mdev_no_group branch
>  - Delete vfio_group_get_from_dev() as well due to the rebase
> v1: https://lore.kernel.org/r/0-v1-7f2292e6b2ba+44839-vfio_get_from_dev_jgg@nvidia.com
> 
> Jason Gunthorpe (2):
>   vfio/pci: Have all VFIO PCI drivers store the vfio_pci_core_device in
>     drvdata
>   vfio/pci: Remove vfio_device_get_from_dev()
> 
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 15 +++++--
>  drivers/vfio/pci/mlx5/main.c                  | 15 +++++--
>  drivers/vfio/pci/vfio_pci.c                   |  6 ++-
>  drivers/vfio/pci/vfio_pci_core.c              | 36 +++++-----------
>  drivers/vfio/vfio.c                           | 41 +------------------
>  include/linux/vfio.h                          |  2 -
>  include/linux/vfio_pci_core.h                 |  3 +-
>  7 files changed, 39 insertions(+), 79 deletions(-)

Applied to vfio next branch for v5.19.  Thanks,

Alex