linux-kernel - [PATCH v2 23/26] drm/xe/pf: Add wait helper for VF FLR

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Message-ID: <20251021224133.577765-24-michal.winiarski@intel.com>
Date: Wed, 22 Oct 2025 00:41:30 +0200
From: Michał Winiarski <michal.winiarski@...el.com>
To: 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>, <intel-xe@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>, Matthew Brost
	<matthew.brost@...el.com>, Michal Wajdeczko <michal.wajdeczko@...el.com>
CC: <dri-devel@...ts.freedesktop.org>, 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>, Michał Winiarski
	<michal.winiarski@...el.com>
Subject: [PATCH v2 23/26] drm/xe/pf: Add wait helper for VF FLR

VF FLR requires additional processing done by PF driver.
The processing is done after FLR is already finished from PCIe
perspective.
In order to avoid a scenario where migration state transitions while
PF processing is still in progress, additional synchronization
point is needed.
Add a helper that will be used as part of VF driver struct
pci_error_handlers .reset_done() callback.

Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@...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 aac8ecb861545..bed488476706d 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_control.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
@@ -123,6 +123,30 @@ 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;
+}
+
 /**
  * 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 30318c1fba34e..ef9f219b21096 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_trigger_save_vf(struct xe_device *xe, unsigned int vfid);
 int xe_sriov_pf_control_finish_save_vf(struct xe_device *xe, unsigned int vfid);
-- 
2.50.1