linux-kernel - [PATCH v2 18/26] drm/xe/pf: Add helpers for VF MMIO migration data handling

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Message-ID: <20251021224133.577765-19-michal.winiarski@intel.com>
Date: Wed, 22 Oct 2025 00:41:25 +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 18/26] drm/xe/pf: Add helpers for VF MMIO migration data handling

In an upcoming change, the VF MMIO migration data will be handled as
part of VF control state machine. Add the necessary helpers to allow the
migration data transfer to/from the VF MMIO registers.

Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>
---
 drivers/gpu/drm/xe/xe_gt_sriov_pf.c | 88 +++++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_gt_sriov_pf.h |  6 ++
 2 files changed, 94 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
index c4dda87b47cc8..31ee86166dfd0 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
@@ -194,6 +194,94 @@ static void pf_clear_vf_scratch_regs(struct xe_gt *gt, unsigned int vfid)
 	}
 }
 
+/**
+ * xe_gt_sriov_pf_mmio_vf_size - Get the size of VF MMIO register data.
+ * @gt: the &xe_gt
+ * @vfid: VF identifier
+ *
+ * Return: size in bytes.
+ */
+size_t xe_gt_sriov_pf_mmio_vf_size(struct xe_gt *gt, unsigned int vfid)
+{
+	if (xe_gt_is_media_type(gt))
+		return MED_VF_SW_FLAG_COUNT * sizeof(u32);
+	else
+		return VF_SW_FLAG_COUNT * sizeof(u32);
+}
+
+/**
+ * xe_gt_sriov_pf_mmio_vf_save - Save VF MMIO register values to a buffer.
+ * @gt: the &xe_gt
+ * @vfid: VF identifier
+ * @buf: destination buffer
+ * @size: destination buffer size in bytes
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_gt_sriov_pf_mmio_vf_save(struct xe_gt *gt, unsigned int vfid, void *buf, size_t size)
+{
+	u32 stride = pf_get_vf_regs_stride(gt_to_xe(gt));
+	struct xe_reg scratch;
+	u32 *regs = buf;
+	int n, count;
+
+	if (size != xe_gt_sriov_pf_mmio_vf_size(gt, vfid))
+		return -EINVAL;
+
+	if (xe_gt_is_media_type(gt)) {
+		count = MED_VF_SW_FLAG_COUNT;
+		for (n = 0; n < count; n++) {
+			scratch = xe_reg_vf_to_pf(MED_VF_SW_FLAG(n), vfid, stride);
+			regs[n] = xe_mmio_read32(&gt->mmio, scratch);
+		}
+	} else {
+		count = VF_SW_FLAG_COUNT;
+		for (n = 0; n < count; n++) {
+			scratch = xe_reg_vf_to_pf(VF_SW_FLAG(n), vfid, stride);
+			regs[n] = xe_mmio_read32(&gt->mmio, scratch);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * xe_gt_sriov_pf_mmio_vf_restore - Restore VF MMIO register values from a buffer.
+ * @gt: the &xe_gt
+ * @vfid: VF identifier
+ * @buf: source buffer
+ * @size: source buffer size in bytes
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_gt_sriov_pf_mmio_vf_restore(struct xe_gt *gt, unsigned int vfid,
+				   const void *buf, size_t size)
+{
+	u32 stride = pf_get_vf_regs_stride(gt_to_xe(gt));
+	const u32 *regs = buf;
+	struct xe_reg scratch;
+	int n, count;
+
+	if (size != xe_gt_sriov_pf_mmio_vf_size(gt, vfid))
+		return -EINVAL;
+
+	if (xe_gt_is_media_type(gt)) {
+		count = MED_VF_SW_FLAG_COUNT;
+		for (n = 0; n < count; n++) {
+			scratch = xe_reg_vf_to_pf(MED_VF_SW_FLAG(n), vfid, stride);
+			xe_mmio_write32(&gt->mmio, scratch, regs[n]);
+		}
+	} else {
+		count = VF_SW_FLAG_COUNT;
+		for (n = 0; n < count; n++) {
+			scratch = xe_reg_vf_to_pf(VF_SW_FLAG(n), vfid, stride);
+			xe_mmio_write32(&gt->mmio, scratch, regs[n]);
+		}
+	}
+
+	return 0;
+}
+
 /**
  * xe_gt_sriov_pf_sanitize_hw() - Reset hardware state related to a VF.
  * @gt: the &xe_gt
diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf.h b/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
index e7fde3f9937af..7f4f1fda5f77a 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
@@ -6,6 +6,8 @@
 #ifndef _XE_GT_SRIOV_PF_H_
 #define _XE_GT_SRIOV_PF_H_
 
+#include <linux/types.h>
+
 struct xe_gt;
 
 #ifdef CONFIG_PCI_IOV
@@ -16,6 +18,10 @@ void xe_gt_sriov_pf_init_hw(struct xe_gt *gt);
 void xe_gt_sriov_pf_sanitize_hw(struct xe_gt *gt, unsigned int vfid);
 void xe_gt_sriov_pf_stop_prepare(struct xe_gt *gt);
 void xe_gt_sriov_pf_restart(struct xe_gt *gt);
+size_t xe_gt_sriov_pf_mmio_vf_size(struct xe_gt *gt, unsigned int vfid);
+int xe_gt_sriov_pf_mmio_vf_save(struct xe_gt *gt, unsigned int vfid, void *buf, size_t size);
+int xe_gt_sriov_pf_mmio_vf_restore(struct xe_gt *gt, unsigned int vfid,
+				   const void *buf, size_t size);
 #else
 static inline int xe_gt_sriov_pf_init_early(struct xe_gt *gt)
 {
-- 
2.50.1