Re: [PATCH v1 6/7] drm/xe/vf: Rebase MEMIRQ structures for all contexts after migration

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

On 14.05.2025 00:49, Tomasz Lis wrote:
> All contexts require an update of state data, as the data includes
> GGTT references to memirq-related buffers.
> 
> Default contexts need these references updated as well, because they
> are not refreshed when a new context is created from them.
> 
> Signed-off-by: Tomasz Lis <tomasz.lis@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_lrc.c      | 41 ++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_lrc.h      |  2 ++
>  drivers/gpu/drm/xe/xe_sriov_vf.c | 17 +++++++++++--
>  3 files changed, 58 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
> index 43e1c18e1769..5a7f0077ef31 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -898,6 +898,47 @@ static void *empty_lrc_data(struct xe_hw_engine *hwe)
>  	return data;
>  }
>  
> +/**
> + * xe_default_lrc_update_memirq_regs_with_address - Re-compute GGTT references in default LRC
> + *   of given engine.
> + * @hwe: the &xe_hw_engine struct instance
> + */
> +void xe_default_lrc_update_memirq_regs_with_address(struct xe_hw_engine *hwe)
> +{
> +	struct xe_gt *gt = hwe->gt;
> +	u32 *regs;
> +
> +	if (!gt->default_lrc[hwe->class])
> +		return;
> +
> +	regs = gt->default_lrc[hwe->class] + LRC_PPHWSP_SIZE;
> +	set_memory_based_intr(regs, hwe);
> +}
> +
> +/**
> + * xe_lrc_update_memirq_regs_with_address - Re-compute GGTT references in mem interrupt data
> + *   for given LRC.
> + * @hwe: the &xe_hw_engine struct instance
> + * @lrc: the &xe_lrc struct instance
> + */
> +void xe_lrc_update_memirq_regs_with_address(struct xe_hw_engine *hwe, struct xe_lrc *lrc)
> +{
> +	struct xe_gt *gt = hwe->gt;
> +	struct iosys_map map;
> +	size_t regs_len;
> +	u32 *regs;
> +
> +	map = __xe_lrc_regs_map(lrc);
> +	regs_len = lrc_reg_size(gt_to_xe(gt));
> +	regs = kzalloc(regs_len, GFP_ATOMIC);
> +	if (!regs)
> +		return;

no error ? but recovery will be now broken, no?

> +	xe_map_memcpy_from(gt_to_xe(gt), regs, &map, 0, regs_len);
> +	set_memory_based_intr(regs, hwe);
> +	xe_map_memcpy_to(gt_to_xe(gt), &map, 0, regs, regs_len);
> +	kfree(regs);

maybe instead of this alloc + RMW + free just update:

	[CTX_INT_MASK_ENABLE_PTR]
	[CTX_INT_STATUS_REPORT_PTR]
	[CTX_INT_SRC_REPORT_PTR]

using 3x xe_lrc_write_ctx_reg() like it was done in patch 5/7 ?

> +}
> +
>  static void xe_lrc_set_ppgtt(struct xe_lrc *lrc, struct xe_vm *vm)
>  {
>  	u64 desc = xe_vm_pdp4_descriptor(vm, gt_to_tile(lrc->gt));
> diff --git a/drivers/gpu/drm/xe/xe_lrc.h b/drivers/gpu/drm/xe/xe_lrc.h
> index e7a99cfd0abe..3f0ae3affafe 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.h
> +++ b/drivers/gpu/drm/xe/xe_lrc.h
> @@ -89,6 +89,8 @@ u32 xe_lrc_indirect_ring_ggtt_addr(struct xe_lrc *lrc);
>  u32 xe_lrc_ggtt_addr(struct xe_lrc *lrc);
>  u32 *xe_lrc_regs(struct xe_lrc *lrc);
>  void xe_lrc_update_hwctx_regs_with_address(struct xe_lrc *lrc);
> +void xe_default_lrc_update_memirq_regs_with_address(struct xe_hw_engine *hwe);
> +void xe_lrc_update_memirq_regs_with_address(struct xe_hw_engine *hwe, struct xe_lrc *lrc);
>  
>  u32 xe_lrc_read_ctx_reg(struct xe_lrc *lrc, int reg_nr);
>  void xe_lrc_write_ctx_reg(struct xe_lrc *lrc, int reg_nr, u32 val);
> diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.c b/drivers/gpu/drm/xe/xe_sriov_vf.c
> index 016faa29cddd..c08c44dbd383 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_vf.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_vf.c
> @@ -225,12 +225,23 @@ static int vf_post_migration_requery_guc(struct xe_device *xe)
>  	return ret;
>  }
>  
> +static void xe_gt_default_lrcs_hwsp_rebase(struct xe_gt *gt)
> +{
> +	struct xe_hw_engine *hwe;
> +	enum xe_hw_engine_id id;
> +
> +	for_each_hw_engine(hwe, gt, id)
> +		xe_default_lrc_update_memirq_regs_with_address(hwe);
> +}
> +
>  static void xe_exec_queue_contexts_hwsp_rebase(struct xe_exec_queue *eq)
>  {
>  	int i;
>  
> -	for (i = 0; i < eq->width; ++i)
> +	for (i = 0; i < eq->width; ++i) {
> +		xe_lrc_update_memirq_regs_with_address(eq->hwe, eq->lrc[i]);
>  		xe_lrc_update_hwctx_regs_with_address(eq->lrc[i]);
> +	}
>  }
>  
>  static void xe_guc_contexts_hwsp_rebase(struct xe_guc *guc)
> @@ -249,8 +260,10 @@ static void vf_post_migration_fixup_contexts(struct xe_device *xe)
>  	struct xe_gt *gt;
>  	unsigned int id;
>  
> -	for_each_gt(gt, xe, id)
> +	for_each_gt(gt, xe, id) {
> +		xe_gt_default_lrcs_hwsp_rebase(gt);
>  		xe_guc_contexts_hwsp_rebase(&gt->uc.guc);
> +	}
>  }
>  
>  static void vf_post_migration_fixup_ctb(struct xe_device *xe)