Re: [PATCH v4 5/6] drm/xe/lrc: Allow to add user commands on context switch

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Thu, Sep 11, 2025 at 12:36:29PM -0700, Lucas De Marchi wrote:
> During validation it's useful to allows additional commands to be
> executed on context switch. Fetch the commands from configfs (to be
> added) and add them to the WA BB.
> 
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
> v2: Fix warning when building without configfs
> ---
>  drivers/gpu/drm/xe/xe_configfs.c | 13 +++++++++++++
>  drivers/gpu/drm/xe/xe_configfs.h |  6 ++++++
>  drivers/gpu/drm/xe/xe_lrc.c      | 25 +++++++++++++++++++++++++
>  3 files changed, 44 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
> index 45fdb6cf26b5d..d86c75af03278 100644
> --- a/drivers/gpu/drm/xe/xe_configfs.c
> +++ b/drivers/gpu/drm/xe/xe_configfs.c
> @@ -633,6 +633,19 @@ bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev)
>  	return ret;
>  }
>  
> +/**
> + * xe_configfs_get_ctx_restore_post_bb - get configfs ctx_restore_post_bb setting
> + * @pdev: pci device
> + *
> + * Return: post_ctx_restore setting in configfs
> + */
> +u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev,
> +					enum xe_engine_class class,
> +					const u32 **cs)
> +{
> +	return 0;
> +}
> +
>  int __init xe_configfs_init(void)
>  {
>  	int ret;
> diff --git a/drivers/gpu/drm/xe/xe_configfs.h b/drivers/gpu/drm/xe/xe_configfs.h
> index 1402e863b71c0..eff2645b5f593 100644
> --- a/drivers/gpu/drm/xe/xe_configfs.h
> +++ b/drivers/gpu/drm/xe/xe_configfs.h
> @@ -8,6 +8,8 @@
>  #include <linux/limits.h>
>  #include <linux/types.h>
>  
> +#include <xe_hw_engine_types.h>
> +
>  struct pci_dev;
>  
>  #if IS_ENABLED(CONFIG_CONFIGFS_FS)
> @@ -17,6 +19,8 @@ void xe_configfs_check_device(struct pci_dev *pdev);
>  bool xe_configfs_get_survivability_mode(struct pci_dev *pdev);
>  u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev);
>  bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev);
> +u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev, enum xe_engine_class,
> +					const u32 **cs);
>  #else
>  static inline int xe_configfs_init(void) { return 0; }
>  static inline void xe_configfs_exit(void) { }
> @@ -24,6 +28,8 @@ static inline void xe_configfs_check_device(struct pci_dev *pdev) { }
>  static inline bool xe_configfs_get_survivability_mode(struct pci_dev *pdev) { return false; }
>  static inline u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev) { return U64_MAX; }
>  static inline bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev) { return false; }
> +static inline u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev, enum xe_engine_class,
> +						      const u32 **cs) { return 0; }
>  #endif
>  
>  #endif
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
> index 6d52e0eb97f54..f337954066f55 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -16,6 +16,7 @@
>  #include "regs/xe_lrc_layout.h"
>  #include "xe_bb.h"
>  #include "xe_bo.h"
> +#include "xe_configfs.h"
>  #include "xe_device.h"
>  #include "xe_drm_client.h"
>  #include "xe_exec_queue_types.h"
> @@ -1102,6 +1103,29 @@ static ssize_t setup_timestamp_wa(struct xe_lrc *lrc, struct xe_hw_engine *hwe,
>  	return cmd - batch;
>  }
>  
> +static ssize_t setup_configfs_post_ctx_restore_bb(struct xe_lrc *lrc,
> +						  struct xe_hw_engine *hwe,
> +						  u32 *batch, size_t max_len)
> +{
> +	struct xe_device *xe = gt_to_xe(lrc->gt);
> +	const u32 *user_batch;
> +	u32 *cmd = batch;
> +	u32 count;
> +
> +	count = xe_configfs_get_ctx_restore_post_bb(to_pci_dev(xe->drm.dev),
> +						    hwe->class, &user_batch);
> +	if (!count)
> +		return 0;
> +
> +	if (count > max_len)
> +		return -ENOSPC;
> +
> +	memcpy(cmd, user_batch, count * sizeof(u32));

shouldn't we use copy_from_user here?

> +	cmd += count;
> +
> +	return cmd - batch;
> +}
> +
>  static ssize_t setup_invalidate_state_cache_wa(struct xe_lrc *lrc,
>  					       struct xe_hw_engine *hwe,
>  					       u32 *batch, size_t max_len)
> @@ -1203,6 +1227,7 @@ int xe_lrc_setup_wa_bb_with_scratch(struct xe_lrc *lrc, struct xe_hw_engine *hwe
>  		{ .setup = setup_timestamp_wa },
>  		{ .setup = setup_invalidate_state_cache_wa },
>  		{ .setup = setup_utilization_wa },
> +		{ .setup = setup_configfs_post_ctx_restore_bb },
>  	};
>  	struct bo_setup_state state = {
>  		.lrc = lrc,
> 
> -- 
> 2.50.1
>