Re: [PATCH 26/26] vfio/xe: Add vendor-specific vfio_pci driver for Intel graphics

Rodrigo Vivi
2025-10-13T19:00:32Z

On Sat, Oct 11, 2025 at 09:38:47PM +0200, Michał Winiarski wrote:
> In addition to generic VFIO PCI functionality, the driver implements
> VFIO migration uAPI, allowing userspace to enable migration for Intel
> Graphics SR-IOV Virtual Functions.
> The driver binds to VF device, and uses API exposed by Xe driver bound
> to PF device to control VF device state and transfer the migration data.
>
> Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
> ---
> MAINTAINERS | 7 +
> drivers/vfio/pci/Kconfig | 2 +
> drivers/vfio/pci/Makefile | 2 +
> drivers/vfio/pci/xe/Kconfig | 12 +
> drivers/vfio/pci/xe/Makefile | 3 +
> drivers/vfio/pci/xe/main.c | 470 +++++++++++++++++++++++++++++++++++
> 6 files changed, 496 insertions(+)
> create mode 100644 drivers/vfio/pci/xe/Kconfig
> create mode 100644 drivers/vfio/pci/xe/Makefile
> create mode 100644 drivers/vfio/pci/xe/main.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d46e9f2aaf2ad..ce84b021e6679 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -26567,6 +26567,13 @@ L: virtualization@lists.linux.dev
> S: Maintained
> F: drivers/vfio/pci/virtio
>
> +VFIO XE PCI DRIVER
> +M: Michał Winiarski <michal.winiarski@intel.com>
> +L: kvm@vger.kernel.org
> +L: intel-xe@lists.freedesktop.org
> +S: Supported
> +F: drivers/vfio/pci/xe

Just to confirm:

The patch flow towards drm-xe-next right? or for future changes
that doesn't depend on the xe necessarily you plan to send through some
kvm tree?

Either way,

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> +
> VGA_SWITCHEROO
> R: Lukas Wunner <lukas@wunner.de>
> S: Maintained
> diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig
> index 2b0172f546652..c100f0ab87f2d 100644
> --- a/drivers/vfio/pci/Kconfig
> +++ b/drivers/vfio/pci/Kconfig
> @@ -67,4 +67,6 @@ source "drivers/vfio/pci/nvgrace-gpu/Kconfig"
>
> source "drivers/vfio/pci/qat/Kconfig"
>
> +source "drivers/vfio/pci/xe/Kconfig"
> +
> endmenu
> diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
> index cf00c0a7e55c8..f5d46aa9347b9 100644
> --- a/drivers/vfio/pci/Makefile
> +++ b/drivers/vfio/pci/Makefile
> @@ -19,3 +19,5 @@ obj-$(CONFIG_VIRTIO_VFIO_PCI) += virtio/
> obj-$(CONFIG_NVGRACE_GPU_VFIO_PCI) += nvgrace-gpu/
>
> obj-$(CONFIG_QAT_VFIO_PCI) += qat/
> +
> +obj-$(CONFIG_XE_VFIO_PCI) += xe/
> diff --git a/drivers/vfio/pci/xe/Kconfig b/drivers/vfio/pci/xe/Kconfig
> new file mode 100644
> index 0000000000000..787be88268685
> --- /dev/null
> +++ b/drivers/vfio/pci/xe/Kconfig
> @@ -0,0 +1,12 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +config XE_VFIO_PCI
> + tristate "VFIO support for Intel Graphics"
> + depends on DRM_XE
> + select VFIO_PCI_CORE
> + help
> + This option enables vendor-specific VFIO driver for Intel Graphics.
> + In addition to generic VFIO PCI functionality, it implements VFIO
> + migration uAPI allowing userspace to enable migration for
> + Intel Graphics SR-IOV Virtual Functions supported by the Xe driver.
> +
> + If you don't know what to do here, say N.
> diff --git a/drivers/vfio/pci/xe/Makefile b/drivers/vfio/pci/xe/Makefile
> new file mode 100644
> index 0000000000000..13aa0fd192cd4
> --- /dev/null
> +++ b/drivers/vfio/pci/xe/Makefile
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_XE_VFIO_PCI) += xe-vfio-pci.o
> +xe-vfio-pci-y := main.o
> diff --git a/drivers/vfio/pci/xe/main.c b/drivers/vfio/pci/xe/main.c
> new file mode 100644
> index 0000000000000..b9109b6812eb2
> --- /dev/null
> +++ b/drivers/vfio/pci/xe/main.c
> @@ -0,0 +1,470 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright © 2025 Intel Corporation
> + */
> +
> +#include <linux/anon_inodes.h>
> +#include <linux/delay.h>
> +#include <linux/file.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/sizes.h>
> +#include <linux/types.h>
> +#include <linux/vfio.h>
> +#include <linux/vfio_pci_core.h>
> +
> +#include <drm/intel/xe_sriov_vfio.h>
> +
> +/**
> + * struct xe_vfio_pci_migration_file - file used for reading / writing migration data
> + */
> +struct xe_vfio_pci_migration_file {
> + /** @filp: pointer to underlying &struct file */
> + struct file *filp;
> + /** @lock: serializes accesses to migration data */
> + struct mutex lock;
> + /** @xe_vdev: backpointer to &struct xe_vfio_pci_core_device */
> + struct xe_vfio_pci_core_device *xe_vdev;
> +};
> +
> +/**
> + * struct xe_vfio_pci_core_device - xe-specific vfio_pci_core_device
> + *
> + * Top level structure of xe_vfio_pci.
> + */
> +struct xe_vfio_pci_core_device {
> + /** @core_device: vendor-agnostic VFIO device */
> + struct vfio_pci_core_device core_device;
> +
> + /** @mig_state: current device migration state */
> + enum vfio_device_mig_state mig_state;
> +
> + /** @vfid: VF number used by PF, xe uses 1-based indexing for vfid */
> + unsigned int vfid;
> +
> + /** @pf: pointer to driver_private of physical function */
> + struct pci_dev *pf;
> +
> + /** @fd: &struct xe_vfio_pci_migration_file for userspace to read/write migration data */
> + struct xe_vfio_pci_migration_file *fd;
> +};
> +
> +#define xe_vdev_to_dev(xe_vdev) (&(xe_vdev)->core_device.pdev->dev)
> +#define xe_vdev_to_pdev(xe_vdev) ((xe_vdev)->core_device.pdev)
> +
> +static void xe_vfio_pci_disable_file(struct xe_vfio_pci_migration_file *migf)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev = migf->xe_vdev;
> +
> + mutex_lock(&migf->lock);
> + xe_vdev->fd = NULL;
> + mutex_unlock(&migf->lock);
> +}
> +
> +static void xe_vfio_pci_reset(struct xe_vfio_pci_core_device *xe_vdev)
> +{
> + if (xe_vdev->fd)
> + xe_vfio_pci_disable_file(xe_vdev->fd);
> +
> + xe_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
> +}
> +
> +static void xe_vfio_pci_reset_done(struct pci_dev *pdev)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev = pci_get_drvdata(pdev);
> + int ret;
> +
> + ret = xe_sriov_vfio_wait_flr_done(xe_vdev->pf, xe_vdev->vfid);
> + if (ret)
> + dev_err(&pdev->dev, "Failed to wait for FLR: %d\n", ret);
> +
> + xe_vfio_pci_reset(xe_vdev);
> +}
> +
> +static const struct pci_error_handlers xe_vfio_pci_err_handlers = {
> + .reset_done = xe_vfio_pci_reset_done,
> +};
> +
> +static int xe_vfio_pci_open_device(struct vfio_device *core_vdev)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev =
> + container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
> + struct vfio_pci_core_device *vdev = &xe_vdev->core_device;
> + int ret;
> +
> + ret = vfio_pci_core_enable(vdev);
> + if (ret)
> + return ret;
> +
> + vfio_pci_core_finish_enable(vdev);
> +
> + return 0;
> +}
> +
> +static int xe_vfio_pci_release_file(struct inode *inode, struct file *filp)
> +{
> + struct xe_vfio_pci_migration_file *migf = filp->private_data;
> +
> + xe_vfio_pci_disable_file(migf);
> + mutex_destroy(&migf->lock);
> + kfree(migf);
> +
> + return 0;
> +}
> +
> +static ssize_t xe_vfio_pci_save_read(struct file *filp, char __user *buf, size_t len, loff_t *pos)
> +{
> + struct xe_vfio_pci_migration_file *migf = filp->private_data;
> + ssize_t ret;
> +
> + if (pos)
> + return -ESPIPE;
> +
> + mutex_lock(&migf->lock);
> + ret = xe_sriov_vfio_data_read(migf->xe_vdev->pf, migf->xe_vdev->vfid, buf, len);
> + mutex_unlock(&migf->lock);
> +
> + return ret;
> +}
> +
> +static const struct file_operations xe_vfio_pci_save_fops = {
> + .owner = THIS_MODULE,
> + .read = xe_vfio_pci_save_read,
> + .release = xe_vfio_pci_release_file,
> + .llseek = noop_llseek,
> +};
> +
> +static ssize_t xe_vfio_pci_resume_write(struct file *filp, const char __user *buf,
> + size_t len, loff_t *pos)
> +{
> + struct xe_vfio_pci_migration_file *migf = filp->private_data;
> + ssize_t ret;
> +
> + if (pos)
> + return -ESPIPE;
> +
> + mutex_lock(&migf->lock);
> + ret = xe_sriov_vfio_data_write(migf->xe_vdev->pf, migf->xe_vdev->vfid, buf, len);
> + mutex_unlock(&migf->lock);
> +
> + return ret;
> +}
> +
> +static const struct file_operations xe_vfio_pci_resume_fops = {
> + .owner = THIS_MODULE,
> + .write = xe_vfio_pci_resume_write,
> + .release = xe_vfio_pci_release_file,
> + .llseek = noop_llseek,
> +};
> +
> +static const char *vfio_dev_state_str(u32 state)
> +{
> + switch (state) {
> + case VFIO_DEVICE_STATE_RUNNING: return "running";
> + case VFIO_DEVICE_STATE_RUNNING_P2P: return "running_p2p";
> + case VFIO_DEVICE_STATE_STOP_COPY: return "stopcopy";
> + case VFIO_DEVICE_STATE_STOP: return "stop";
> + case VFIO_DEVICE_STATE_RESUMING: return "resuming";
> + case VFIO_DEVICE_STATE_ERROR: return "error";
> + default: return "";
> + }
> +}
> +
> +enum xe_vfio_pci_file_type {
> + XE_VFIO_FILE_SAVE = 0,
> + XE_VFIO_FILE_RESUME,
> +};
> +
> +static struct xe_vfio_pci_migration_file *
> +xe_vfio_pci_alloc_file(struct xe_vfio_pci_core_device *xe_vdev,
> + enum xe_vfio_pci_file_type type)
> +{
> + struct xe_vfio_pci_migration_file *migf;
> + const struct file_operations *fops;
> + int flags;
> +
> + migf = kzalloc(sizeof(*migf), GFP_KERNEL);
> + if (!migf)
> + return ERR_PTR(-ENOMEM);
> +
> + fops = type == XE_VFIO_FILE_SAVE ? &xe_vfio_pci_save_fops : &xe_vfio_pci_resume_fops;
> + flags = type == XE_VFIO_FILE_SAVE ? O_RDONLY : O_WRONLY;
> + migf->filp = anon_inode_getfile("xe_vfio_mig", fops, migf, flags);
> + if (IS_ERR(migf->filp)) {
> + kfree(migf);
> + return ERR_CAST(migf->filp);
> + }
> +
> + mutex_init(&migf->lock);
> + migf->xe_vdev = xe_vdev;
> + xe_vdev->fd = migf;
> +
> + stream_open(migf->filp->f_inode, migf->filp);
> +
> + return migf;
> +}
> +
> +static struct file *
> +xe_vfio_set_state(struct xe_vfio_pci_core_device *xe_vdev, u32 new)
> +{
> + u32 cur = xe_vdev->mig_state;
> + int ret;
> +
> + dev_dbg(xe_vdev_to_dev(xe_vdev),
> + "state: %s->%s\n", vfio_dev_state_str(cur), vfio_dev_state_str(new));
> +
> + /*
> + * "STOP" handling is reused for "RUNNING_P2P", as the device doesn't have the capability to
> + * selectively block p2p DMA transfers.
> + * The device is not processing new workload requests when the VF is stopped, and both
> + * memory and MMIO communication channels are transferred to destination (where processing
> + * will be resumed).
> + */
> + if ((cur == VFIO_DEVICE_STATE_RUNNING && new == VFIO_DEVICE_STATE_STOP) ||
> + (cur == VFIO_DEVICE_STATE_RUNNING && new == VFIO_DEVICE_STATE_RUNNING_P2P)) {
> + ret = xe_sriov_vfio_stop(xe_vdev->pf, xe_vdev->vfid);
> + if (ret)
> + goto err;
> +
> + return NULL;
> + }
> +
> + if ((cur == VFIO_DEVICE_STATE_RUNNING_P2P && new == VFIO_DEVICE_STATE_STOP) ||
> + (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_RUNNING_P2P))
> + return NULL;
> +
> + if ((cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_RUNNING) ||
> + (cur == VFIO_DEVICE_STATE_RUNNING_P2P && new == VFIO_DEVICE_STATE_RUNNING)) {
> + ret = xe_sriov_vfio_run(xe_vdev->pf, xe_vdev->vfid);
> + if (ret)
> + goto err;
> +
> + return NULL;
> + }
> +
> + if (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_STOP_COPY) {
> + struct xe_vfio_pci_migration_file *migf;
> +
> + migf = xe_vfio_pci_alloc_file(xe_vdev, XE_VFIO_FILE_SAVE);
> + if (IS_ERR(migf)) {
> + ret = PTR_ERR(migf);
> + goto err;
> + }
> +
> + ret = xe_sriov_vfio_stop_copy_enter(xe_vdev->pf, xe_vdev->vfid);
> + if (ret) {
> + fput(migf->filp);
> + goto err;
> + }
> +
> + return migf->filp;
> + }
> +
> + if ((cur == VFIO_DEVICE_STATE_STOP_COPY && new == VFIO_DEVICE_STATE_STOP)) {
> + if (xe_vdev->fd)
> + xe_vfio_pci_disable_file(xe_vdev->fd);
> +
> + xe_sriov_vfio_stop_copy_exit(xe_vdev->pf, xe_vdev->vfid);
> +
> + return NULL;
> + }
> +
> + if (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_RESUMING) {
> + struct xe_vfio_pci_migration_file *migf;
> +
> + migf = xe_vfio_pci_alloc_file(xe_vdev, XE_VFIO_FILE_RESUME);
> + if (IS_ERR(migf)) {
> + ret = PTR_ERR(migf);
> + goto err;
> + }
> +
> + ret = xe_sriov_vfio_resume_enter(xe_vdev->pf, xe_vdev->vfid);
> + if (ret) {
> + fput(migf->filp);
> + goto err;
> + }
> +
> + return migf->filp;
> + }
> +
> + if (cur == VFIO_DEVICE_STATE_RESUMING && new == VFIO_DEVICE_STATE_STOP) {
> + if (xe_vdev->fd)
> + xe_vfio_pci_disable_file(xe_vdev->fd);
> +
> + xe_sriov_vfio_resume_exit(xe_vdev->pf, xe_vdev->vfid);
> +
> + return NULL;
> + }
> +
> + if (new == VFIO_DEVICE_STATE_ERROR)
> + xe_sriov_vfio_error(xe_vdev->pf, xe_vdev->vfid);
> +
> + WARN(true, "Unknown state transition %d->%d", cur, new);
> + return ERR_PTR(-EINVAL);
> +
> +err:
> + dev_dbg(xe_vdev_to_dev(xe_vdev),
> + "Failed to transition state: %s->%s err=%d\n",
> + vfio_dev_state_str(cur), vfio_dev_state_str(new), ret);
> + return ERR_PTR(ret);
> +}
> +
> +static struct file *
> +xe_vfio_pci_set_device_state(struct vfio_device *core_vdev,
> + enum vfio_device_mig_state new_state)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev =
> + container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
> + enum vfio_device_mig_state next_state;
> + struct file *f = NULL;
> + int ret;
> +
> + while (new_state != xe_vdev->mig_state) {
> + ret = vfio_mig_get_next_state(core_vdev, xe_vdev->mig_state,
> + new_state, &next_state);
> + if (ret) {
> + f = ERR_PTR(ret);
> + break;
> + }
> + f = xe_vfio_set_state(xe_vdev, next_state);
> + if (IS_ERR(f))
> + break;
> +
> + xe_vdev->mig_state = next_state;
> +
> + /* Multiple state transitions with non-NULL file in the middle */
> + if (f && new_state != xe_vdev->mig_state) {
> + fput(f);
> + f = ERR_PTR(-EINVAL);
> + break;
> + }
> + }
> +
> + return f;
> +}
> +
> +static int xe_vfio_pci_get_device_state(struct vfio_device *core_vdev,
> + enum vfio_device_mig_state *curr_state)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev =
> + container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
> +
> + *curr_state = xe_vdev->mig_state;
> +
> + return 0;
> +}
> +
> +static int xe_vfio_pci_get_data_size(struct vfio_device *vdev,
> + unsigned long *stop_copy_length)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev =
> + container_of(vdev, struct xe_vfio_pci_core_device, core_device.vdev);
> +
> + *stop_copy_length = xe_sriov_vfio_stop_copy_size(xe_vdev->pf, xe_vdev->vfid);
> +
> + return 0;
> +}
> +
> +static const struct vfio_migration_ops xe_vfio_pci_migration_ops = {
> + .migration_set_state = xe_vfio_pci_set_device_state,
> + .migration_get_state = xe_vfio_pci_get_device_state,
> + .migration_get_data_size = xe_vfio_pci_get_data_size,
> +};
> +
> +static void xe_vfio_pci_migration_init(struct vfio_device *core_vdev)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev =
> + container_of(core_vdev, struct xe_vfio_pci_core_device, core_device.vdev);
> + struct pci_dev *pdev = to_pci_dev(core_vdev->dev);
> +
> + if (!xe_sriov_vfio_migration_supported(pdev->physfn))
> + return;
> +
> + /* vfid starts from 1 for xe */
> + xe_vdev->vfid = pci_iov_vf_id(pdev) + 1;
> + xe_vdev->pf = pdev->physfn;
> +
> + core_vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P;
> + core_vdev->mig_ops = &xe_vfio_pci_migration_ops;
> +}
> +
> +static int xe_vfio_pci_init_dev(struct vfio_device *core_vdev)
> +{
> + struct pci_dev *pdev = to_pci_dev(core_vdev->dev);
> +
> + if (pdev->is_virtfn && strcmp(pdev->physfn->dev.driver->name, "xe") == 0)
> + xe_vfio_pci_migration_init(core_vdev);
> +
> + return vfio_pci_core_init_dev(core_vdev);
> +}
> +
> +static const struct vfio_device_ops xe_vfio_pci_ops = {
> + .name = "xe-vfio-pci",
> + .init = xe_vfio_pci_init_dev,
> + .release = vfio_pci_core_release_dev,
> + .open_device = xe_vfio_pci_open_device,
> + .close_device = vfio_pci_core_close_device,
> + .ioctl = vfio_pci_core_ioctl,
> + .device_feature = vfio_pci_core_ioctl_feature,
> + .read = vfio_pci_core_read,
> + .write = vfio_pci_core_write,
> + .mmap = vfio_pci_core_mmap,
> + .request = vfio_pci_core_request,
> + .match = vfio_pci_core_match,
> + .match_token_uuid = vfio_pci_core_match_token_uuid,
> + .bind_iommufd = vfio_iommufd_physical_bind,
> + .unbind_iommufd = vfio_iommufd_physical_unbind,
> + .attach_ioas = vfio_iommufd_physical_attach_ioas,
> + .detach_ioas = vfio_iommufd_physical_detach_ioas,
> +};
> +
> +static int xe_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev;
> + int ret;
> +
> + xe_vdev = vfio_alloc_device(xe_vfio_pci_core_device, core_device.vdev, &pdev->dev,
> + &xe_vfio_pci_ops);
> + if (IS_ERR(xe_vdev))
> + return PTR_ERR(xe_vdev);
> +
> + dev_set_drvdata(&pdev->dev, &xe_vdev->core_device);
> +
> + ret = vfio_pci_core_register_device(&xe_vdev->core_device);
> + if (ret) {
> + vfio_put_device(&xe_vdev->core_device.vdev);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void xe_vfio_pci_remove(struct pci_dev *pdev)
> +{
> + struct xe_vfio_pci_core_device *xe_vdev = pci_get_drvdata(pdev);
> +
> + vfio_pci_core_unregister_device(&xe_vdev->core_device);
> + vfio_put_device(&xe_vdev->core_device.vdev);
> +}
> +
> +static const struct pci_device_id xe_vfio_pci_table[] = {
> + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
> + .class = PCI_BASE_CLASS_DISPLAY << 8, .class_mask = 0xff << 16,
> + .override_only = PCI_ID_F_VFIO_DRIVER_OVERRIDE },
> + {}
> +};
> +MODULE_DEVICE_TABLE(pci, xe_vfio_pci_table);
> +
> +static struct pci_driver xe_vfio_pci_driver = {
> + .name = "xe-vfio-pci",
> + .id_table = xe_vfio_pci_table,
> + .probe = xe_vfio_pci_probe,
> + .remove = xe_vfio_pci_remove,
> + .err_handler = &xe_vfio_pci_err_handlers,
> + .driver_managed_dma = true,
> +};
> +module_pci_driver(xe_vfio_pci_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_DESCRIPTION("VFIO PCI driver with migration support for Intel Graphics");
> --
> 2.50.1
>