Re: [PATCH v2 22/26] drm/xe/pf: Handle VRAM migration data as part of PF control

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

On 10/22/2025 12:41 AM, Michał Winiarski wrote:
> Connect the helpers to allow save and restore of VRAM migration data in
> stop_copy / resume device state.
> 
> Co-developed-by: Lukasz Laguna <lukasz.laguna@intel.com>
> Signed-off-by: Lukasz Laguna <lukasz.laguna@intel.com>
> Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c   |  18 ++
>  .../gpu/drm/xe/xe_gt_sriov_pf_control_types.h |   2 +
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c | 222 ++++++++++++++++++
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.h |   6 +
>  .../drm/xe/xe_gt_sriov_pf_migration_types.h   |   3 +
>  drivers/gpu/drm/xe/xe_sriov_pf_control.c      |   3 +
>  6 files changed, 254 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
> index e7156ad3d1839..680f2de44144b 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
> @@ -191,6 +191,7 @@ static const char *control_bit_to_string(enum xe_gt_sriov_control_bits bit)
>  	CASE2STR(SAVE_DATA_GUC);
>  	CASE2STR(SAVE_DATA_GGTT);
>  	CASE2STR(SAVE_DATA_MMIO);
> +	CASE2STR(SAVE_DATA_VRAM);
>  	CASE2STR(SAVE_DATA_DONE);
>  	CASE2STR(SAVE_FAILED);
>  	CASE2STR(SAVED);
> @@ -832,6 +833,7 @@ static void pf_exit_vf_save_wip(struct xe_gt *gt, unsigned int vfid)
>  		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_GGTT);
>  		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_MMIO);
>  		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_DONE);
> +		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_VRAM);
>  	}
>  }
>  
> @@ -885,6 +887,19 @@ static int pf_handle_vf_save_data(struct xe_gt *gt, unsigned int vfid)
>  		ret = xe_gt_sriov_pf_migration_mmio_save(gt, vfid);
>  		if (ret)
>  			return ret;
> +
> +		pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_VRAM);
> +		return -EAGAIN;
> +	}
> +
> +	if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_VRAM)) {
> +		if (xe_gt_sriov_pf_migration_vram_size(gt, vfid) > 0) {
> +			ret = xe_gt_sriov_pf_migration_vram_save(gt, vfid);
> +			if (ret == -EAGAIN)
> +				pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_VRAM);
> +			if (ret)
> +				return ret;
> +		}
>  	}
>  
>  	return 0;
> @@ -1100,6 +1115,9 @@ pf_handle_vf_restore_data(struct xe_gt *gt, unsigned int vfid)
>  	case XE_SRIOV_MIGRATION_DATA_TYPE_GUC:
>  		ret = xe_gt_sriov_pf_migration_guc_restore(gt, vfid, data);
>  		break;
> +	case XE_SRIOV_MIGRATION_DATA_TYPE_VRAM:
> +		ret = xe_gt_sriov_pf_migration_vram_restore(gt, vfid, data);
> +		break;
>  	default:
>  		xe_gt_sriov_notice(gt, "Skipping VF%u unknown data type: %d\n", vfid, data->type);
>  		break;
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control_types.h b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control_types.h
> index 9dfcebd5078ac..fba10136f7cc7 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control_types.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control_types.h
> @@ -36,6 +36,7 @@
>   * @XE_GT_SRIOV_STATE_SAVE_DATA_GUC: indicates PF needs to save VF GuC migration data.
>   * @XE_GT_SRIOV_STATE_SAVE_DATA_GGTT: indicates PF needs to save VF GGTT migration data.
>   * @XE_GT_SRIOV_STATE_SAVE_DATA_MMIO: indicates PF needs to save VF MMIO migration data.
> + * @XE_GT_SRIOV_STATE_SAVE_DATA_VRAM: indicates PF needs to save VF VRAM migration data.
>   * @XE_GT_SRIOV_STATE_SAVE_DATA_DONE: indicates that all migration data was produced by Xe.
>   * @XE_GT_SRIOV_STATE_SAVE_FAILED: indicates that VF save operation has failed.
>   * @XE_GT_SRIOV_STATE_SAVED: indicates that VF data is saved.
> @@ -82,6 +83,7 @@ enum xe_gt_sriov_control_bits {
>  	XE_GT_SRIOV_STATE_SAVE_DATA_GUC,
>  	XE_GT_SRIOV_STATE_SAVE_DATA_GGTT,
>  	XE_GT_SRIOV_STATE_SAVE_DATA_MMIO,
> +	XE_GT_SRIOV_STATE_SAVE_DATA_VRAM,
>  	XE_GT_SRIOV_STATE_SAVE_DATA_DONE,
>  	XE_GT_SRIOV_STATE_SAVE_FAILED,
>  	XE_GT_SRIOV_STATE_SAVED,
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c
> index 41335b15ffdbe..2c6a86d98ee31 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c
> @@ -17,6 +17,7 @@
>  #include "xe_gt_sriov_printk.h"
>  #include "xe_guc_buf.h"
>  #include "xe_guc_ct.h"
> +#include "xe_migrate.h"
>  #include "xe_sriov.h"
>  #include "xe_sriov_migration_data.h"
>  #include "xe_sriov_pf_migration.h"
> @@ -485,6 +486,220 @@ int xe_gt_sriov_pf_migration_mmio_restore(struct xe_gt *gt, unsigned int vfid,
>  	return pf_restore_vf_mmio_mig_data(gt, vfid, data);
>  }
>  
> +/**
> + * xe_gt_sriov_pf_migration_vram_size() - Get the size of VF VRAM migration data.
> + * @gt: the &xe_gt
> + * @vfid: the VF identifier
> + *
> + * This function is for PF only.
> + *
> + * Return: size in bytes or a negative error code on failure.
> + */
> +ssize_t xe_gt_sriov_pf_migration_vram_size(struct xe_gt *gt, unsigned int vfid)
> +{
> +	if (gt != xe_root_mmio_gt(gt_to_xe(gt)))

probably you mean

	if (!xe_gt_is_main_type(gt))

> +		return 0;
> +
> +	return xe_gt_sriov_pf_config_get_lmem(gt, vfid);
> +}
> +
> +static struct dma_fence *__pf_save_restore_vram(struct xe_gt *gt, unsigned int vfid,
> +						struct xe_bo *vram, u64 vram_offset,
> +						struct xe_bo *sysmem, u64 sysmem_offset,
> +						size_t size, bool save)
> +{
> +	struct dma_fence *ret = NULL;
> +	struct drm_exec exec;
> +	int err;
> +
> +	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> +	drm_exec_until_all_locked(&exec) {
> +		err = drm_exec_lock_obj(&exec, &vram->ttm.base);
> +		drm_exec_retry_on_contention(&exec);
> +		if (err) {
> +			ret = ERR_PTR(err);
> +			goto err;
> +		}
> +
> +		err = drm_exec_lock_obj(&exec, &sysmem->ttm.base);
> +		drm_exec_retry_on_contention(&exec);
> +		if (err) {
> +			ret = ERR_PTR(err);
> +			goto err;
> +		}
> +	}
> +
> +	ret = xe_migrate_vram_copy_chunk(vram, vram_offset, sysmem, sysmem_offset, size,
> +					 save ? XE_MIGRATE_COPY_TO_SRAM : XE_MIGRATE_COPY_TO_VRAM);
> +
> +err:
> +	drm_exec_fini(&exec);
> +
> +	return ret;
> +}
> +
> +static int pf_save_vram_chunk(struct xe_gt *gt, unsigned int vfid,
> +			      struct xe_bo *src_vram, u64 src_vram_offset,
> +			      size_t size)
> +{
> +	struct xe_sriov_migration_data *data;
> +	struct dma_fence *fence;
> +	int ret;
> +
> +	data = xe_sriov_migration_data_alloc(gt_to_xe(gt));
> +	if (!data)
> +		return -ENOMEM;
> +
> +	ret = xe_sriov_migration_data_init(data, gt->tile->id, gt->info.id,
> +					   XE_SRIOV_MIGRATION_DATA_TYPE_VRAM,
> +					   src_vram_offset, size);
> +	if (ret)
> +		goto fail;
> +
> +	fence = __pf_save_restore_vram(gt, vfid,
> +				       src_vram, src_vram_offset,
> +				       data->bo, 0, size, true);
> +
> +	ret = dma_fence_wait_timeout(fence, false, 5 * HZ);
> +	dma_fence_put(fence);
> +	if (!ret) {
> +		ret = -ETIME;
> +		goto fail;
> +	}
> +
> +	pf_dump_mig_data(gt, vfid, data);
> +
> +	ret = xe_gt_sriov_pf_migration_save_produce(gt, vfid, data);
> +	if (ret)
> +		goto fail;
> +
> +	return 0;
> +
> +fail:
> +	xe_sriov_migration_data_free(data);
> +	return ret;
> +}
> +
> +#define VF_VRAM_STATE_CHUNK_MAX_SIZE SZ_512M
> +static int pf_save_vf_vram_mig_data(struct xe_gt *gt, unsigned int vfid)
> +{
> +	struct xe_gt_sriov_migration_data *migration = pf_pick_gt_migration(gt, vfid);
> +	loff_t *offset = &migration->vram_save_offset;
> +	struct xe_bo *vram;
> +	size_t vram_size, chunk_size;
> +	int ret;
> +
> +	vram = xe_gt_sriov_pf_config_get_lmem_obj(gt, vfid);
> +	if (!vram)
> +		return -ENXIO;

no error message ?

> +
> +	vram_size = xe_bo_size(vram);
> +	chunk_size = min(vram_size - *offset, VF_VRAM_STATE_CHUNK_MAX_SIZE);

what if *offset > vram_size ?

> +
> +	ret = pf_save_vram_chunk(gt, vfid, vram, *offset, chunk_size);
> +	if (ret)
> +		goto fail;
> +
> +	*offset += chunk_size;
> +
> +	xe_bo_put(vram);
> +
> +	if (*offset < vram_size)
> +		return -EAGAIN;
> +
> +	return 0;
> +
> +fail:
> +	xe_bo_put(vram);
> +	xe_gt_sriov_err(gt, "Failed to save VF%u VRAM data (%pe)\n", vfid, ERR_PTR(ret));
> +	return ret;
> +}
> +
> +static int pf_restore_vf_vram_mig_data(struct xe_gt *gt, unsigned int vfid,
> +				       struct xe_sriov_migration_data *data)
> +{
> +	u64 end = data->hdr.offset + data->hdr.size;
> +	struct dma_fence *fence;
> +	struct xe_bo *vram;
> +	size_t size;
> +	int ret = 0;
> +
> +	vram = xe_gt_sriov_pf_config_get_lmem_obj(gt, vfid);
> +	if (!vram)
> +		return -ENXIO;

no error message ? other errors are reported

> +
> +	size = xe_bo_size(vram);
> +
> +	if (end > size || end < data->hdr.size) {
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	pf_dump_mig_data(gt, vfid, data);
> +
> +	fence = __pf_save_restore_vram(gt, vfid, vram, data->hdr.offset,
> +				       data->bo, 0, data->hdr.size, false);
> +	ret = dma_fence_wait_timeout(fence, false, 5 * HZ);

define this timeout at least as macro (if not as helper function, as this might be platform/settings specific)

> +	dma_fence_put(fence);
> +	if (!ret) {
> +		ret = -ETIME;
> +		goto err;
> +	}
> +
> +	return 0;
> +err:
> +	xe_bo_put(vram);
> +	xe_gt_sriov_err(gt, "Failed to restore VF%u VRAM data (%pe)\n", vfid, ERR_PTR(ret));
> +	return ret;
> +}
> +
> +/**
> + * xe_gt_sriov_pf_migration_vram_save() - Save VF VRAM migration data.
> + * @gt: the &xe_gt
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * This function is for PF only.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_gt_sriov_pf_migration_vram_save(struct xe_gt *gt, unsigned int vfid)
> +{
> +	xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
> +	xe_gt_assert(gt, vfid != PFID);
> +	xe_gt_assert(gt, vfid <= xe_sriov_pf_get_totalvfs(gt_to_xe(gt)));
> +
> +	return pf_save_vf_vram_mig_data(gt, vfid);
> +}
> +
> +/**
> + * xe_gt_sriov_pf_migration_vram_restore() - Restore VF VRAM migration data.
> + * @gt: the &xe_gt
> + * @vfid: the VF identifier (can't be 0)
> + *
> + * This function is for PF only.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_gt_sriov_pf_migration_vram_restore(struct xe_gt *gt, unsigned int vfid,
> +					  struct xe_sriov_migration_data *data)
> +{
> +	xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
> +	xe_gt_assert(gt, vfid != PFID);
> +	xe_gt_assert(gt, vfid <= xe_sriov_pf_get_totalvfs(gt_to_xe(gt)));
> +
> +	return pf_restore_vf_vram_mig_data(gt, vfid, data);
> +}
> +
> +/**
> + * xe_gt_sriov_pf_migration_save_init() - Initialize per-GT migration related data.
> + * @gt: the &xe_gt
> + * @vfid: the VF identifier (can't be 0)
> + */
> +void xe_gt_sriov_pf_migration_save_init(struct xe_gt *gt, unsigned int vfid)
> +{
> +	pf_pick_gt_migration(gt, vfid)->vram_save_offset = 0;
> +}
> +
>  /**
>   * xe_gt_sriov_pf_migration_size() - Total size of migration data from all components within a GT.
>   * @gt: the &xe_gt
> @@ -522,6 +737,13 @@ ssize_t xe_gt_sriov_pf_migration_size(struct xe_gt *gt, unsigned int vfid)
>  		size += sizeof(struct xe_sriov_pf_migration_hdr);
>  	total += size;
>  
> +	size = xe_gt_sriov_pf_migration_vram_size(gt, vfid);
> +	if (size < 0)
> +		return size;
> +	else if (size > 0)

"else" not needed

> +		size += sizeof(struct xe_sriov_pf_migration_hdr);
> +	total += size;
> +
>  	return total;
>  }
>  
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.h b/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.h
> index 24a233c4cd0bb..ca518eda5429f 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.h
> @@ -27,6 +27,12 @@ ssize_t xe_gt_sriov_pf_migration_mmio_size(struct xe_gt *gt, unsigned int vfid);
>  int xe_gt_sriov_pf_migration_mmio_save(struct xe_gt *gt, unsigned int vfid);
>  int xe_gt_sriov_pf_migration_mmio_restore(struct xe_gt *gt, unsigned int vfid,
>  					  struct xe_sriov_migration_data *data);
> +ssize_t xe_gt_sriov_pf_migration_vram_size(struct xe_gt *gt, unsigned int vfid);
> +int xe_gt_sriov_pf_migration_vram_save(struct xe_gt *gt, unsigned int vfid);
> +int xe_gt_sriov_pf_migration_vram_restore(struct xe_gt *gt, unsigned int vfid,
> +					  struct xe_sriov_migration_data *data);
> +
> +void xe_gt_sriov_pf_migration_save_init(struct xe_gt *gt, unsigned int vfid);
>  
>  ssize_t xe_gt_sriov_pf_migration_size(struct xe_gt *gt, unsigned int vfid);
>  
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration_types.h b/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration_types.h
> index 75d8b94cbbefb..39a940c9b0a4b 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration_types.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration_types.h
> @@ -16,6 +16,9 @@
>  struct xe_gt_sriov_migration_data {
>  	/** @ring: queue containing VF save / restore migration data */
>  	struct ptr_ring ring;
> +
> +	/** @vram_save_offset: offset within VRAM, used for chunked VRAM save */

"last saved offset" ?
> +	loff_t vram_save_offset;
>  };
>  
>  #endif
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_control.c b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
> index c2768848daba1..aac8ecb861545 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_control.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
> @@ -5,6 +5,7 @@
>  
>  #include "xe_device.h"
>  #include "xe_gt_sriov_pf_control.h"
> +#include "xe_gt_sriov_pf_migration.h"
>  #include "xe_sriov_migration_data.h"
>  #include "xe_sriov_pf_control.h"
>  #include "xe_sriov_printk.h"
> @@ -171,6 +172,8 @@ int xe_sriov_pf_control_trigger_save_vf(struct xe_device *xe, unsigned int vfid)
>  		return ret;
>  
>  	for_each_gt(gt, xe, id) {
> +		xe_gt_sriov_pf_migration_save_init(gt, vfid);
> +
>  		ret = xe_gt_sriov_pf_control_trigger_save_vf(gt, vfid);
>  		if (ret)
>  			return ret;