Re: [PATCH 25/26] drm/xe/pf: Export helpers for VFIO

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 10/11/2025 9:38 PM, Michał Winiarski wrote:
> Vendor-specific VFIO driver for Xe will implement VF migration.
> Export everything that's needed for migration ops.
> 
> Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
> ---
>  drivers/gpu/drm/xe/Makefile        |   2 +
>  drivers/gpu/drm/xe/xe_sriov_vfio.c | 252 +++++++++++++++++++++++++++++
>  include/drm/intel/xe_sriov_vfio.h  |  28 ++++
>  3 files changed, 282 insertions(+)
>  create mode 100644 drivers/gpu/drm/xe/xe_sriov_vfio.c
>  create mode 100644 include/drm/intel/xe_sriov_vfio.h
> 
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index e253d65366de4..a5c5afff42aa6 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -181,6 +181,8 @@ xe-$(CONFIG_PCI_IOV) += \
>  	xe_sriov_pf_service.o \
>  	xe_tile_sriov_pf_debugfs.o
>  
> +xe-$(CONFIG_XE_VFIO_PCI) += xe_sriov_vfio.o
> +
>  # include helpers for tests even when XE is built-in
>  ifdef CONFIG_DRM_XE_KUNIT_TEST
>  xe-y += tests/xe_kunit_helpers.o
> diff --git a/drivers/gpu/drm/xe/xe_sriov_vfio.c b/drivers/gpu/drm/xe/xe_sriov_vfio.c
> new file mode 100644
> index 0000000000000..a510d1bde93f0
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_sriov_vfio.c
> @@ -0,0 +1,252 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2025 Intel Corporation
> + */
> +
> +#include <drm/intel/xe_sriov_vfio.h>
> +
> +#include "xe_pm.h"
> +#include "xe_sriov.h"
> +#include "xe_sriov_pf_control.h"
> +#include "xe_sriov_pf_migration.h"
> +#include "xe_sriov_pf_migration_data.h"
> +
> +/**
> + * xe_sriov_vfio_migration_supported() - Check if migration is supported.
> + * @pdev: PF PCI device
> + *
> + * Return: true if migration is supported, false otherwise.
> + */
> +bool xe_sriov_vfio_migration_supported(struct pci_dev *pdev)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;
> +
> +	return xe_sriov_pf_migration_supported(xe);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_migration_supported, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_wait_flr_done - Wait for VF FLR completion.
> + * @pdev: PF PCI device
> + * @vfid: VF identifier

or

 * @pdev: the PF struct &pci_dev device
 * @vfid: the VF identifier (can't be 0)

> + *
> + * This function will wait until VF FLR is processed by PF on all tiles (or
> + * until timeout occurs).
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_wait_flr_done(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;

you also need to validate:

	vfid != PFID
and
	vfid <= xe_sriov_pf_get_totalvfs()

this applies to all exported functions below
> +
> +	return xe_sriov_pf_control_wait_flr(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_wait_flr_done, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_stop - Stop VF.
> + * @pdev: PF PCI device
> + * @vfid: VF identifier
> + *
> + * This function will pause VF on all tiles/GTs.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_stop(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +	int ret;
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;
> +
> +	xe_pm_runtime_get(xe);

maybe we should use xe_pm_runtime_get_if_active() to avoid awaking PF if there are no VFs?

when VFs are enabled xe_pm_runtime_get_if_active() will always return true


> +	ret = xe_sriov_pf_control_pause_vf(xe, vfid);
> +	xe_pm_runtime_put(xe);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_stop, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_run - Run VF.
> + * @pdev: PF PCI device
> + * @vfid: VF identifier
> + *
> + * This function will resume VF on all tiles.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_run(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +	int ret;
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;
> +
> +	xe_pm_runtime_get(xe);
> +	ret = xe_sriov_pf_control_resume_vf(xe, vfid);
> +	xe_pm_runtime_put(xe);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_run, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_stop_copy_enter - Copy VF migration data from device (while stopped).
> + * @pdev: PF PCI device
> + * @vfid: VF identifier
> + *
> + * This function will save VF migration data on all tiles.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_stop_copy_enter(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +	int ret;
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;
> +
> +	xe_pm_runtime_get(xe);
> +	ret = xe_sriov_pf_control_save_vf(xe, vfid);
> +	xe_pm_runtime_put(xe);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_stop_copy_enter, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_stop_copy_exit - Wait until VF migration data save is done.
> + * @pdev: PF PCI device
> + * @vfid: VF identifier
> + *
> + * This function will wait until VF migration data is saved on all tiles.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_stop_copy_exit(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +	int ret;
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;
> +
> +	xe_pm_runtime_get(xe);
> +	ret = xe_sriov_pf_control_wait_save_vf(xe, vfid);
> +	xe_pm_runtime_put(xe);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_stop_copy_exit, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_resume_enter - Copy VF migration data to device (while stopped).
> + * @pdev: PF PCI device
> + * @vfid: VF identifier
> + *
> + * This function will restore VF migration data on all tiles.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_resume_enter(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +	int ret;
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;
> +
> +	xe_pm_runtime_get(xe);
> +	ret = xe_sriov_pf_control_restore_vf(xe, vfid);
> +	xe_pm_runtime_put(xe);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_resume_enter, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_resume_exit - Wait until VF migration data is copied to the device.
> + * @pdev: PF PCI device
> + * @vfid: VF identifier
> + *
> + * This function will wait until VF migration data is restored on all tiles.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_resume_exit(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +	int ret;
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;
> +
> +	xe_pm_runtime_get(xe);
> +	ret = xe_sriov_pf_control_wait_restore_vf(xe, vfid);
> +	xe_pm_runtime_put(xe);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_resume_exit, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_error - Move VF to error state.
> + * @pdev: PF PCI device
> + * @vfid: VF identifier
> + *
> + * This function will stop VF on all tiles.
> + * Reset is needed to move it out of error state.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_error(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +	int ret;
> +
> +	if (!IS_SRIOV_PF(xe))
> +		return -ENODEV;
> +
> +	xe_pm_runtime_get(xe);
> +	ret = xe_sriov_pf_control_stop_vf(xe, vfid);
> +	xe_pm_runtime_put(xe);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_error, "xe-vfio-pci");
> +

add kernel-doc

> +ssize_t xe_sriov_vfio_data_read(struct pci_dev *pdev, unsigned int vfid,
> +				char __user *buf, size_t len)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);

missing param validation

	is PF
	is valid VFID

no RPM ?

> +
> +	return xe_sriov_pf_migration_data_read(xe, vfid, buf, len);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_data_read, "xe-vfio-pci");
> +
> +ssize_t xe_sriov_vfio_data_write(struct pci_dev *pdev, unsigned int vfid,
> +				 const char __user *buf, size_t len)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +
> +	return xe_sriov_pf_migration_data_write(xe, vfid, buf, len);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_data_write, "xe-vfio-pci");
> +
> +ssize_t xe_sriov_vfio_stop_copy_size(struct pci_dev *pdev, unsigned int vfid)
> +{
> +	struct xe_device *xe = pci_get_drvdata(pdev);
> +
> +	return xe_sriov_pf_migration_size(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_stop_copy_size, "xe-vfio-pci");
> diff --git a/include/drm/intel/xe_sriov_vfio.h b/include/drm/intel/xe_sriov_vfio.h
> new file mode 100644
> index 0000000000000..24e272f84c0e6
> --- /dev/null
> +++ b/include/drm/intel/xe_sriov_vfio.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2025 Intel Corporation
> + */
> +
> +#ifndef _XE_SRIOV_VFIO_H_
> +#define _XE_SRIOV_VFIO_H_
> +
> +#include <linux/types.h>
> +
> +struct pci_dev;
> +
> +bool xe_sriov_vfio_migration_supported(struct pci_dev *pdev);
> +int xe_sriov_vfio_wait_flr_done(struct pci_dev *pdev, unsigned int vfid);
> +int xe_sriov_vfio_stop(struct pci_dev *pdev, unsigned int vfid);
> +int xe_sriov_vfio_run(struct pci_dev *pdev, unsigned int vfid);
> +int xe_sriov_vfio_stop_copy_enter(struct pci_dev *pdev, unsigned int vfid);
> +int xe_sriov_vfio_stop_copy_exit(struct pci_dev *pdev, unsigned int vfid);
> +int xe_sriov_vfio_resume_enter(struct pci_dev *pdev, unsigned int vfid);
> +int xe_sriov_vfio_resume_exit(struct pci_dev *pdev, unsigned int vfid);
> +int xe_sriov_vfio_error(struct pci_dev *pdev, unsigned int vfid);
> +ssize_t xe_sriov_vfio_data_read(struct pci_dev *pdev, unsigned int vfid,
> +				char __user *buf, size_t len);
> +ssize_t xe_sriov_vfio_data_write(struct pci_dev *pdev, unsigned int vfid,
> +				 const char __user *buf, size_t len);
> +ssize_t xe_sriov_vfio_stop_copy_size(struct pci_dev *pdev, unsigned int vfid);
> +
> +#endif /* _XE_SRIOV_VFIO_H_ */

this is a very simple header, no need to repeat include guard name here