Re: [PATCH v5 24/28] drm/xe/pf: Enable SR-IOV VF migration

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

On 11/11/2025 2:04 AM, Michał Winiarski wrote:
> All of the necessary building blocks are now in place to support SR-IOV
> VF migration.
> Flip the enable/disable logic to match VF code and disable the feature
> only for platforms that don't meet the necessary pre-requisites.

typo: prerequisites

> 
> Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c | 12 +++++++
>  drivers/gpu/drm/xe/xe_sriov_pf_migration.c    | 32 ++++++++++++++++---
>  drivers/gpu/drm/xe/xe_sriov_pf_migration.h    |  1 +
>  .../gpu/drm/xe/xe_sriov_pf_migration_types.h  |  4 +--
>  4 files changed, 42 insertions(+), 7 deletions(-)
> 
> 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 6ad948e96fd45..0a0c3145e1274 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_pf_helpers.h"
>  #include "xe_gt_sriov_pf_migration.h"
>  #include "xe_gt_sriov_printk.h"
> +#include "xe_guc.h"
>  #include "xe_guc_buf.h"
>  #include "xe_guc_ct.h"
>  #include "xe_migrate.h"
> @@ -1008,6 +1009,15 @@ static void action_ring_cleanup(void *arg)
>  	ptr_ring_cleanup(r, destroy_pf_packet);
>  }
>  
> +static void pf_gt_migration_check_support(struct xe_gt *gt)
> +{
> +	if (IS_ENABLED(CONFIG_DRM_XE_DEBUG))
> +		return;

maybe instead of blindly ignoring all checks in the debug mode, let them go
and just in xe_sriov_pf_migration_disable() don't set disabled=true or
ignore .disabled flag in xe_sriov_pf_migration_supported() ?

then we could still experiment in debug mode without any restrictions,
but have some logs about missing official prerequisites 

> +
> +	if (GUC_FIRMWARE_VER(&gt->uc.guc) < MAKE_GUC_VER(70, 54, 0))
> +		xe_sriov_pf_migration_disable(gt_to_xe(gt), "requires GuC version >= 70.54.0");
> +}
> +
>  /**
>   * xe_gt_sriov_pf_migration_init() - Initialize support for VF migration.
>   * @gt: the &xe_gt
> @@ -1024,6 +1034,8 @@ int xe_gt_sriov_pf_migration_init(struct xe_gt *gt)
>  
>  	xe_gt_assert(gt, IS_SRIOV_PF(xe));
>  
> +	pf_gt_migration_check_support(gt);
> +
>  	if (!pf_migration_supported(gt))
>  		return 0;
>  
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_migration.c b/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
> index d6c24bea759af..7dd7625e5aeed 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
> @@ -46,13 +46,34 @@ bool xe_sriov_pf_migration_supported(struct xe_device *xe)
>  {
>  	xe_assert(xe, IS_SRIOV_PF(xe));
>  
> -	return xe->sriov.pf.migration.supported;
> +	return !xe->sriov.pf.migration.disabled;

	return IS_ENABLED(CONFIG_DRM_XE_DEBUG) || !xe->sriov.pf.migration.disabled;

>  }
>  
> -static bool pf_check_migration_support(struct xe_device *xe)
> +/**
> + * xe_sriov_pf_migration_disable - Turn off SR-IOV VF migration support on PF.

    * xe_sriov_pf_migration_disable() - ...

> + * @xe: the &xe_device instance.
> + * @fmt: format string for the log message, to be combined with following VAs.
> + */
> +void xe_sriov_pf_migration_disable(struct xe_device *xe, const char *fmt, ...)
> +{
> +	struct va_format vaf;
> +	va_list va_args;
> +
> +	xe_assert(xe, IS_SRIOV_PF(xe));
> +
> +	va_start(va_args, fmt);
> +	vaf.fmt = fmt;
> +	vaf.va  = &va_args;
> +	xe_sriov_notice(xe, "migration disabled: %pV\n", &vaf);

	"migration %s: %pV\n",
		IS_ENABLED(CONFIG_DRM_XE_DEBUG) ?
		"missing prerequisite" : "disabled"

> +	va_end(va_args);
> +
> +	xe->sriov.pf.migration.disabled = true;
> +}
> +
> +static void pf_migration_check_support(struct xe_device *xe)
>  {
> -	/* XXX: for now this is for feature enabling only */
> -	return IS_ENABLED(CONFIG_DRM_XE_DEBUG);
> +	if (!xe_device_has_memirq(xe))
> +		xe_sriov_pf_migration_disable(xe, "requires memory-based IRQ support");
>  }
>  
>  static void pf_migration_cleanup(void *arg)
> @@ -77,7 +98,8 @@ int xe_sriov_pf_migration_init(struct xe_device *xe)
>  
>  	xe_assert(xe, IS_SRIOV_PF(xe));
>  
> -	xe->sriov.pf.migration.supported = pf_check_migration_support(xe);
> +	pf_migration_check_support(xe);
> +
>  	if (!xe_sriov_pf_migration_supported(xe))
>  		return 0;
>  
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_migration.h b/drivers/gpu/drm/xe/xe_sriov_pf_migration.h
> index b806298a0bb62..f8f408df84813 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_migration.h
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_migration.h
> @@ -14,6 +14,7 @@ struct xe_sriov_packet;
>  
>  int xe_sriov_pf_migration_init(struct xe_device *xe);
>  bool xe_sriov_pf_migration_supported(struct xe_device *xe);
> +void xe_sriov_pf_migration_disable(struct xe_device *xe, const char *fmt, ...);
>  int xe_sriov_pf_migration_restore_produce(struct xe_device *xe, unsigned int vfid,
>  					  struct xe_sriov_packet *data);
>  struct xe_sriov_packet *
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_migration_types.h b/drivers/gpu/drm/xe/xe_sriov_pf_migration_types.h
> index 363d673ee1dd5..7d9a8a278d915 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_migration_types.h
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_migration_types.h
> @@ -14,8 +14,8 @@
>   * struct xe_sriov_pf_migration - Xe device level VF migration data
>   */
>  struct xe_sriov_pf_migration {
> -	/** @supported: indicates whether VF migration feature is supported */
> -	bool supported;
> +	/** @disabled: indicates whether VF migration feature is disabled */
> +	bool disabled;
>  };
>  
>  /**