[PATCH v6 3/4] drm/xe/ggtt: Initialize GGTT pools by SR-IOV mode

["Piórkowski, Piotr" <piotr.piorkowski@intel.com>]

From: Piotr Piórkowski <piotr.piorkowski@intel.com>

GGTT initialization currently uses the full available range for both the
usable and shareable pools, regardless of the SR-IOV mode. The range is
read from hardware on native and PF devices and assigned by GuC on VFs.

Separate range discovery from pool setup and initialize the pools based on
SR-IOV mode. Native and VF modes use only the usable pool. Shared PF mode
uses both pools over the same full range, so they fully overlap.

v2:
 - Rename the native range discovery helper to ggtt_probe().
 - Treat out-of-range VF GGTT as invalid instead of clamping it.
 - Move GGTT range logging into the common initialization path.

Assisted-by: Claude:claude-5-sonnet
Signed-off-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <dev@lankhorst.se>
---
 drivers/gpu/drm/xe/xe_ggtt.c | 129 ++++++++++++++++++++++++++---------
 1 file changed, 96 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_ggtt.c b/drivers/gpu/drm/xe/xe_ggtt.c
index 8c8354d47782d..2173c4bd26a90 100644
--- a/drivers/gpu/drm/xe/xe_ggtt.c
+++ b/drivers/gpu/drm/xe/xe_ggtt.c
@@ -390,9 +390,99 @@ static void ggtt_init_ranges(struct xe_ggtt *ggtt, u64 start, u64 full_size,
 	drm_mm_init(&ggtt->mm, 0, ggtt->full_size);
 }
 
-int xe_ggtt_init_kunit(struct xe_ggtt *ggtt, u32 start, u32 size)
+static int ggtt_probe(struct xe_ggtt *ggtt, u64 *start, u64 *size)
+{
+	struct xe_device *xe = tile_to_xe(ggtt->tile);
+	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+	unsigned int gsm_size;
+
+	if (GRAPHICS_VERx100(xe) >= 1250)
+		gsm_size = SZ_8M; /* GGTT is expected to be 4GiB */
+	else
+		gsm_size = probe_gsm_size(pdev);
+
+	if (!gsm_size) {
+		xe_log_err_fatal(ggtt->tile, GGTT, -ENOMEM,
+				 "Hardware reported no preallocated GSM\n");
+		return -ENOMEM;
+	}
+
+	*start = xe_wopcm_size(xe);
+	*size = (gsm_size / 8) * (u64)XE_PAGE_SIZE - *start;
+
+	return 0;
+}
+
+static int ggtt_get_range_from_guc(struct xe_ggtt *ggtt, u64 *start, u64 *size)
+{
+	struct xe_device *xe = tile_to_xe(ggtt->tile);
+	u64 wopcm = xe_wopcm_size(xe);
+
+	*start = xe_tile_sriov_vf_ggtt_base(ggtt->tile);
+	*size = xe_tile_sriov_vf_ggtt(ggtt->tile);
+
+	if (*start < wopcm || *start + *size > GUC_GGTT_TOP) {
+		xe_log_err_fatal(ggtt->tile, GGTT, -ERANGE,
+				 "Invalid GGTT configuration: %#llx-%#llx\n",
+				 *start, *start + *size - 1);
+		return -ERANGE;
+	}
+
+	return 0;
+}
+
+static int ggtt_read_available_range(struct xe_ggtt *ggtt, u64 *start, u64 *size)
+{
+	struct xe_device *xe = tile_to_xe(ggtt->tile);
+	int err;
+
+	if (IS_SRIOV_VF(xe))
+		err = ggtt_get_range_from_guc(ggtt, start, size);
+	else
+		err = ggtt_probe(ggtt, start, size);
+	if (err)
+		return err;
+
+	if (!IS_SRIOV_VF(xe) && *start + *size > GUC_GGTT_TOP)
+		*size = GUC_GGTT_TOP - *start;
+
+	return 0;
+}
+
+static void ggtt_init_native(struct xe_ggtt *ggtt, u64 start, u64 size)
 {
 	ggtt_init_ranges(ggtt, start, size, size, 0);
+}
+
+static void ggtt_init_shared(struct xe_ggtt *ggtt, u64 start, u64 size)
+{
+	ggtt_init_ranges(ggtt, start, size, size, size);
+}
+
+static void ggtt_init_generic(struct xe_ggtt *ggtt, u64 start, u64 size)
+{
+	struct xe_device *xe = tile_to_xe(ggtt->tile);
+
+	if (!IS_SRIOV_PF(xe))
+		ggtt_init_native(ggtt, start, size);
+	else
+		ggtt_init_shared(ggtt, start, size);
+
+	xe_tile_info(ggtt->tile, "GGTT usable %#llx-%#llx = %lluK\n",
+		     ggtt->start, ggtt->start + ggtt->size - 1,
+		     ggtt->size / SZ_1K);
+#ifdef CONFIG_PCI_IOV
+	if (IS_SRIOV_PF(xe))
+		xe_tile_info(ggtt->tile, "GGTT shareable %#llx-%#llx = %lluK\n",
+			     ggtt->start + ggtt_shareable_start(ggtt),
+			     ggtt->start + ggtt->full_size - 1,
+			     ggtt->shareable_size / SZ_1K);
+#endif
+}
+
+int xe_ggtt_init_kunit(struct xe_ggtt *ggtt, u32 start, u32 size)
+{
+	ggtt_init_generic(ggtt, start, size);
 	return 0;
 }
 EXPORT_SYMBOL_IF_KUNIT(xe_ggtt_init_kunit);
@@ -420,43 +510,17 @@ static void dev_fini_ggtt(void *arg)
 int xe_ggtt_init_early(struct xe_ggtt *ggtt)
 {
 	struct xe_device *xe = tile_to_xe(ggtt->tile);
-	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
-	unsigned int gsm_size;
-	u64 ggtt_start, wopcm = xe_wopcm_size(xe), ggtt_size;
+	u64 ggtt_start, ggtt_size;
 	int err;
 
-	if (!IS_SRIOV_VF(xe)) {
-		if (GRAPHICS_VERx100(xe) >= 1250)
-			gsm_size = SZ_8M; /* GGTT is expected to be 4GiB */
-		else
-			gsm_size = probe_gsm_size(pdev);
-		if (gsm_size == 0) {
-			xe_log_err_fatal(ggtt->tile, GGTT, -ENOMEM,
-					 "Hardware reported no preallocated GSM\n");
-			return -ENOMEM;
-		}
-		ggtt_start = wopcm;
-		ggtt_size = (gsm_size / 8) * (u64)XE_PAGE_SIZE - ggtt_start;
-	} else {
-		ggtt_start = xe_tile_sriov_vf_ggtt_base(ggtt->tile);
-		ggtt_size = xe_tile_sriov_vf_ggtt(ggtt->tile);
-
-		if (ggtt_start < wopcm ||
-		    ggtt_start + ggtt_size > GUC_GGTT_TOP) {
-			xe_log_err_fatal(ggtt->tile, GGTT, -ERANGE,
-					 "Invalid GGTT configuration: %#llx-%#llx\n",
-					 ggtt_start, ggtt_start + ggtt_size - 1);
-			return -ERANGE;
-		}
-	}
+	err = ggtt_read_available_range(ggtt, &ggtt_start, &ggtt_size);
+	if (err)
+		return err;
 
 	ggtt->gsm = ggtt->tile->mmio.regs + SZ_8M;
 	if (IS_DGFX(xe) && xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K)
 		ggtt->flags |= XE_GGTT_FLAGS_64K;
 
-	if (ggtt_size + ggtt_start > GUC_GGTT_TOP)
-		ggtt_size = GUC_GGTT_TOP - ggtt_start;
-
 	if (GRAPHICS_VERx100(xe) >= 1270)
 		ggtt->pt_ops =
 			(ggtt->tile->media_gt && XE_GT_WA(ggtt->tile->media_gt, 22019338487)) ||
@@ -469,8 +533,7 @@ int xe_ggtt_init_early(struct xe_ggtt *ggtt)
 	if (!ggtt->wq)
 		return -ENOMEM;
 
-	ggtt_init_ranges(ggtt, ggtt_start, ggtt_size, ggtt_size,
-			 IS_SRIOV_PF(xe) ? ggtt_size : 0);
+	ggtt_init_generic(ggtt, ggtt_start, ggtt_size);
 
 	err = drmm_add_action_or_reset(&xe->drm, ggtt_fini_early, ggtt);
 	if (err)
-- 
2.34.1