Re: [PATCH v2 18/26] drm/xe/pf: Add helpers for VF MMIO migration data handling

[Michal Wajdeczko]

On 10/22/2025 12:41 AM, Michał Winiarski wrote:
> In an upcoming change, the VF MMIO migration data will be handled as
> part of VF control state machine. Add the necessary helpers to allow the
> migration data transfer to/from the VF MMIO registers.
> 
> Signed-off-by: Michał Winiarski <michal.winiar...@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_pf.c | 88 +++++++++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_gt_sriov_pf.h |  6 ++

wrong place for those helpers

just promote xe_reg_vf_to_pf()

or maybe it can be done like this:

        void xe_mmio_init_vf(struct xe_mmio *vf, const struct xe_mmio *pf, 
vfid);

then

        struct xe_mmio mmio_vf;

        xe_mmio_init_vf(&mmio_vf, &gt->mmio, vfid);
        val = xe_mmio_read32(&mmio_vf, REG);
        xe_mmio_write32(&mmio_vf, val, REG);

let me try check this out


>  2 files changed, 94 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf.c 
> b/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
> index c4dda87b47cc8..31ee86166dfd0 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
> @@ -194,6 +194,94 @@ static void pf_clear_vf_scratch_regs(struct xe_gt *gt, 
> unsigned int vfid)
>       }
>  }
>  
> +/**
> + * xe_gt_sriov_pf_mmio_vf_size - Get the size of VF MMIO register data.
> + * @gt: the &xe_gt
> + * @vfid: VF identifier
> + *
> + * Return: size in bytes.
> + */
> +size_t xe_gt_sriov_pf_mmio_vf_size(struct xe_gt *gt, unsigned int vfid)
> +{
> +     if (xe_gt_is_media_type(gt))
> +             return MED_VF_SW_FLAG_COUNT * sizeof(u32);
> +     else
> +             return VF_SW_FLAG_COUNT * sizeof(u32);
> +}
> +
> +/**
> + * xe_gt_sriov_pf_mmio_vf_save - Save VF MMIO register values to a buffer.
> + * @gt: the &xe_gt
> + * @vfid: VF identifier
> + * @buf: destination buffer
> + * @size: destination buffer size in bytes
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_gt_sriov_pf_mmio_vf_save(struct xe_gt *gt, unsigned int vfid, void 
> *buf, size_t size)
> +{
> +     u32 stride = pf_get_vf_regs_stride(gt_to_xe(gt));
> +     struct xe_reg scratch;
> +     u32 *regs = buf;
> +     int n, count;
> +
> +     if (size != xe_gt_sriov_pf_mmio_vf_size(gt, vfid))
> +             return -EINVAL;
> +
> +     if (xe_gt_is_media_type(gt)) {
> +             count = MED_VF_SW_FLAG_COUNT;
> +             for (n = 0; n < count; n++) {
> +                     scratch = xe_reg_vf_to_pf(MED_VF_SW_FLAG(n), vfid, 
> stride);
> +                     regs[n] = xe_mmio_read32(&gt->mmio, scratch);
> +             }
> +     } else {
> +             count = VF_SW_FLAG_COUNT;
> +             for (n = 0; n < count; n++) {
> +                     scratch = xe_reg_vf_to_pf(VF_SW_FLAG(n), vfid, stride);
> +                     regs[n] = xe_mmio_read32(&gt->mmio, scratch);
> +             }
> +     }
> +
> +     return 0;
> +}
> +
> +/**
> + * xe_gt_sriov_pf_mmio_vf_restore - Restore VF MMIO register values from a 
> buffer.
> + * @gt: the &xe_gt
> + * @vfid: VF identifier
> + * @buf: source buffer
> + * @size: source buffer size in bytes
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_gt_sriov_pf_mmio_vf_restore(struct xe_gt *gt, unsigned int vfid,
> +                                const void *buf, size_t size)
> +{
> +     u32 stride = pf_get_vf_regs_stride(gt_to_xe(gt));
> +     const u32 *regs = buf;
> +     struct xe_reg scratch;
> +     int n, count;
> +
> +     if (size != xe_gt_sriov_pf_mmio_vf_size(gt, vfid))
> +             return -EINVAL;
> +
> +     if (xe_gt_is_media_type(gt)) {
> +             count = MED_VF_SW_FLAG_COUNT;
> +             for (n = 0; n < count; n++) {
> +                     scratch = xe_reg_vf_to_pf(MED_VF_SW_FLAG(n), vfid, 
> stride);
> +                     xe_mmio_write32(&gt->mmio, scratch, regs[n]);
> +             }
> +     } else {
> +             count = VF_SW_FLAG_COUNT;
> +             for (n = 0; n < count; n++) {
> +                     scratch = xe_reg_vf_to_pf(VF_SW_FLAG(n), vfid, stride);
> +                     xe_mmio_write32(&gt->mmio, scratch, regs[n]);
> +             }
> +     }
> +
> +     return 0;
> +}
> +
>  /**
>   * xe_gt_sriov_pf_sanitize_hw() - Reset hardware state related to a VF.
>   * @gt: the &xe_gt
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf.h 
> b/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
> index e7fde3f9937af..7f4f1fda5f77a 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
> @@ -6,6 +6,8 @@
>  #ifndef _XE_GT_SRIOV_PF_H_
>  #define _XE_GT_SRIOV_PF_H_
>  
> +#include <linux/types.h>
> +
>  struct xe_gt;
>  
>  #ifdef CONFIG_PCI_IOV
> @@ -16,6 +18,10 @@ void xe_gt_sriov_pf_init_hw(struct xe_gt *gt);
>  void xe_gt_sriov_pf_sanitize_hw(struct xe_gt *gt, unsigned int vfid);
>  void xe_gt_sriov_pf_stop_prepare(struct xe_gt *gt);
>  void xe_gt_sriov_pf_restart(struct xe_gt *gt);
> +size_t xe_gt_sriov_pf_mmio_vf_size(struct xe_gt *gt, unsigned int vfid);
> +int xe_gt_sriov_pf_mmio_vf_save(struct xe_gt *gt, unsigned int vfid, void 
> *buf, size_t size);
> +int xe_gt_sriov_pf_mmio_vf_restore(struct xe_gt *gt, unsigned int vfid,
> +                                const void *buf, size_t size);
>  #else
>  static inline int xe_gt_sriov_pf_init_early(struct xe_gt *gt)
>  {