linux-kernel - Re: [PATCH 24/26] drm/xe/pf: Add wait helper for VF FLR

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Message-ID: <b16fcd12-784c-4201-ab42-42d1bb492da1@intel.com>
Date: Mon, 13 Oct 2025 15:49:38 +0200
From: Michal Wajdeczko <michal.wajdeczko@...el.com>
To: Michał Winiarski <michal.winiarski@...el.com>, "Alex
 Williamson" <alex.williamson@...hat.com>, Lucas De Marchi
	<lucas.demarchi@...el.com>, Thomas Hellström
	<thomas.hellstrom@...ux.intel.com>, Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Jason Gunthorpe <jgg@...pe.ca>, Yishai Hadas <yishaih@...dia.com>, Kevin Tian
	<kevin.tian@...el.com>, Shameer Kolothum
	<shameerali.kolothum.thodi@...wei.com>, <intel-xe@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>
CC: <dri-devel@...ts.freedesktop.org>, Matthew Brost
	<matthew.brost@...el.com>, Jani Nikula <jani.nikula@...ux.intel.com>, "Joonas
 Lahtinen" <joonas.lahtinen@...ux.intel.com>, Tvrtko Ursulin
	<tursulin@...ulin.net>, David Airlie <airlied@...il.com>, Simona Vetter
	<simona@...ll.ch>, Lukasz Laguna <lukasz.laguna@...el.com>
Subject: Re: [PATCH 24/26] drm/xe/pf: Add wait helper for VF FLR



On 10/11/2025 9:38 PM, Michał Winiarski wrote:
> VF FLR requires additional processing done by PF driver.
> Add a helper to be used as part of VF driver .reset_done().

this ".reset_done" part might require some explanation/update

> 
> Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>
> ---
>  drivers/gpu/drm/xe/xe_sriov_pf_control.c | 24 ++++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_sriov_pf_control.h |  1 +
>  2 files changed, 25 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_control.c b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
> index 10e1f18aa8b11..24845644f269e 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_control.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
> @@ -122,6 +122,30 @@ int xe_sriov_pf_control_reset_vf(struct xe_device *xe, unsigned int vfid)
>  	return result;
>  }
>  
> +/**
> + * xe_sriov_pf_control_wait_flr() - Wait for a VF reset (FLR) to complete.
> + * @xe: the &xe_device
> + * @vfid: the VF identifier
> + *
> + * This function is for PF only.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_sriov_pf_control_wait_flr(struct xe_device *xe, unsigned int vfid)
> +{
> +	struct xe_gt *gt;
> +	unsigned int id;
> +	int result = 0;
> +	int err;
> +
> +	for_each_gt(gt, xe, id) {
> +		err = xe_gt_sriov_pf_control_wait_flr(gt, vfid);
> +		result = result ? -EUCLEAN : err;
> +	}
> +
> +	return result;
> +}

one might want to call this new wait function from within xe_sriov_pf_control_reset_vf() which does both trigger/wait
but for me it works as is, so with commit message update

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@...el.com>

> +
>  /**
>   * xe_sriov_pf_control_sync_flr() - Synchronize a VF FLR between all GTs.
>   * @xe: the &xe_device
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_control.h b/drivers/gpu/drm/xe/xe_sriov_pf_control.h
> index 512fd21d87c1e..c8ea54768cfaa 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_control.h
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_control.h
> @@ -12,6 +12,7 @@ int xe_sriov_pf_control_pause_vf(struct xe_device *xe, unsigned int vfid);
>  int xe_sriov_pf_control_resume_vf(struct xe_device *xe, unsigned int vfid);
>  int xe_sriov_pf_control_stop_vf(struct xe_device *xe, unsigned int vfid);
>  int xe_sriov_pf_control_reset_vf(struct xe_device *xe, unsigned int vfid);
> +int xe_sriov_pf_control_wait_flr(struct xe_device *xe, unsigned int vfid);
>  int xe_sriov_pf_control_sync_flr(struct xe_device *xe, unsigned int vfid);
>  int xe_sriov_pf_control_save_vf(struct xe_device *xe, unsigned int vfid);
>  int xe_sriov_pf_control_wait_save_vf(struct xe_device *xe, unsigned int vfid);