Re: [PATCH v5 26/28] drm/xe/pf: Export helpers for VFIO

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

On 11/11/2025 2:04 AM, Michał Winiarski wrote:
> Vendor-specific VFIO driver for Xe will implement VF migration.

I guess "Vendor-specific" phrase is not welcomed

> 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 | 247 +++++++++++++++++++++++++++++
>  include/drm/intel/xe_sriov_vfio.h  |  30 ++++
>  3 files changed, 279 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 e4b273b025d2a..eef09c44fbde6 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -184,6 +184,8 @@ xe-$(CONFIG_PCI_IOV) += \
>  	xe_sriov_pf_sysfs.o \
>  	xe_tile_sriov_pf_debugfs.o
>  
> +xe-$(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..5aed2efbf6502
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_sriov_vfio.c
> @@ -0,0 +1,247 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2025 Intel Corporation
> + */
> +
> +#include <drm/intel/xe_sriov_vfio.h>
> +
> +#include "xe_assert.h"
> +#include "xe_pci.h"
> +#include "xe_pm.h"
> +#include "xe_sriov_pf_control.h"
> +#include "xe_sriov_pf_helpers.h"
> +#include "xe_sriov_pf_migration.h"
> +
> +/**
> + * xe_sriov_vfio_get_pf() - Get PF &xe_device.
> + * @pdev: the VF &pci_dev device
> + *
> + * Return: pointer to PF &xe_device, NULL otherwise.
> + */
> +struct xe_device *xe_sriov_vfio_get_pf(struct pci_dev *pdev)
> +{
> +	return xe_pci_get_pf(pdev);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_get_pf, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_migration_supported() - Check if migration is supported.
> + * @xe: the PF &xe_device
> + *

maybe we should mention here (and in all below docs) that this @xe shall
be obtained by calling above xe_sriov_vfio_get_pf() function?

> + * Return: true if migration is supported, false otherwise.
> + */
> +bool xe_sriov_vfio_migration_supported(struct xe_device *xe)
> +{

while xe_sriov_vfio_get_pf() returns only valid PF's @xe, since this is an
exported function, maybe we should add some checks like:

	if (!IS_SRIOV_PF(xe))
		return false;

or at least use asserts to reinforce that:

	xe_assert(xe, IS_SRIOV_PF(xe));

here and in all below functions

> +	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.
> + * @xe: the PF &xe_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 xe_device *xe, unsigned int vfid)
> +{
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));

please move assert (or asserts) to the beginning of the function
(and please be consistent in all 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_suspend_device() - Suspend VF.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * This function will pause VF on all tiles/GTs.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_suspend_device(struct xe_device *xe, unsigned int vfid)
> +{
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));
> +
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	return xe_sriov_pf_control_pause_vf(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_suspend_device, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_resume_device() - Resume VF.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * This function will resume VF on all tiles.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_resume_device(struct xe_device *xe, unsigned int vfid)
> +{
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));
> +
> +	return xe_sriov_pf_control_resume_vf(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_resume_device, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_stop_copy_enter() - Initiate a VF device migration data save.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_stop_copy_enter(struct xe_device *xe, unsigned int vfid)
> +{
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));
> +
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	return xe_sriov_pf_control_trigger_save_vf(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_stop_copy_enter, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_stop_copy_exit() - Finish a VF device migration data save.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_stop_copy_exit(struct xe_device *xe, unsigned int vfid)
> +{
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));
> +
> +	return xe_sriov_pf_control_finish_save_vf(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_stop_copy_exit, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_resume_data_enter() - Initiate a VF device migration data restore.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_resume_data_enter(struct xe_device *xe, unsigned int vfid)
> +{
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));
> +
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	return xe_sriov_pf_control_trigger_restore_vf(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_resume_data_enter, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_resume_data_exit() - Finish a VF device migration data restore.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_vfio_resume_data_exit(struct xe_device *xe, unsigned int vfid)
> +{
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));
> +
> +	return xe_sriov_pf_control_finish_restore_vf(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_resume_data_exit, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_error() - Move VF device to error state.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * 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 xe_device *xe, unsigned int vfid)
> +{
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));
> +
> +	return xe_sriov_pf_control_stop_vf(xe, vfid);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_error, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_data_read() - Read migration data from the VF device.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + * @buf: start address of userspace buffer
> + * @len: requested read size from userspace
> + *
> + * Return: number of bytes that has been successfully read,
> + *	   0 if no more migration data is available, -errno on failure.
> + */
> +ssize_t xe_sriov_vfio_data_read(struct xe_device *xe, unsigned int vfid,
> +				char __user *buf, size_t len)
> +{

what about assert for xe_pm_runtime_suspended ?

> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	return xe_sriov_pf_migration_read(xe, vfid, buf, len);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_data_read, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_data_write() - Write migration data to the VF device.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + * @buf: start address of userspace buffer
> + * @len: requested write size from userspace
> + *
> + * Return: number of bytes that has been successfully written, -errno on failure.
> + */
> +ssize_t xe_sriov_vfio_data_write(struct xe_device *xe, unsigned int vfid,
> +				 const char __user *buf, size_t len)
> +{

ditto

> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	return xe_sriov_pf_migration_write(xe, vfid, buf, len);
> +}
> +EXPORT_SYMBOL_FOR_MODULES(xe_sriov_vfio_data_write, "xe-vfio-pci");
> +
> +/**
> + * xe_sriov_vfio_stop_copy_size() - Get a size estimate of VF device migration data.
> + * @xe: the PF &xe_device
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * Return: migration data size in bytes or a negative error code on failure.
> + */
> +ssize_t xe_sriov_vfio_stop_copy_size(struct xe_device *xe, unsigned int vfid)
> +{
> +	if (vfid == PFID || vfid > xe_sriov_pf_get_totalvfs(xe))
> +		return -EINVAL;
> +
> +	xe_assert(xe, !xe_pm_runtime_suspended(xe));
> +
> +	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..bcd7085a81c55
> --- /dev/null
> +++ b/include/drm/intel/xe_sriov_vfio.h
> @@ -0,0 +1,30 @@
> +/* 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;
> +struct xe_device;
> +
> +struct xe_device *xe_sriov_vfio_get_pf(struct pci_dev *pdev);
> +bool xe_sriov_vfio_migration_supported(struct xe_device *xe);
> +int xe_sriov_vfio_wait_flr_done(struct xe_device *xe, unsigned int vfid);
> +int xe_sriov_vfio_suspend_device(struct xe_device *xe, unsigned int vfid);
> +int xe_sriov_vfio_resume_device(struct xe_device *xe, unsigned int vfid);
> +int xe_sriov_vfio_stop_copy_enter(struct xe_device *xe, unsigned int vfid);
> +int xe_sriov_vfio_stop_copy_exit(struct xe_device *xe, unsigned int vfid);
> +int xe_sriov_vfio_resume_data_enter(struct xe_device *xe, unsigned int vfid);
> +int xe_sriov_vfio_resume_data_exit(struct xe_device *xe, unsigned int vfid);
> +int xe_sriov_vfio_error(struct xe_device *xe, unsigned int vfid);
> +ssize_t xe_sriov_vfio_data_read(struct xe_device *xe, unsigned int vfid,
> +				char __user *buf, size_t len);
> +ssize_t xe_sriov_vfio_data_write(struct xe_device *xe, unsigned int vfid,
> +				 const char __user *buf, size_t len);
> +ssize_t xe_sriov_vfio_stop_copy_size(struct xe_device *xe, unsigned int vfid);
> +
> +#endif