drm/xe/pf: Increase PF GuC Buffer Cache size and use it for VF migration

Contiguous PF GGTT VMAs can be scarce after creating VFs.
Increase the GuC buffer cache size to 8M for PF so that we can fit GuC
migration data (which currently maxes out at just over 4M) and use the
cache instead of allocating fresh BOs.

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patch.msgid.link/20251112132220.516975-13-michal.winiarski@intel.com
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>

Author: mwiniars

drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c

@@ -11,7 +11,7 @@
 #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_sriov.h"
 #include "xe_sriov_packet.h"
@@ -58,73 +58,56 @@ static int pf_send_guc_query_vf_state_size(struct xe_gt *gt, unsigned int vfid)
 
 /* Return: number of state dwords saved or a negative error code on failure */
 static int pf_send_guc_save_vf_state(struct xe_gt *gt, unsigned int vfid,
-				     void *buff, size_t size)
+				     void *dst, size_t size)
 {
 	const int ndwords = size / sizeof(u32);
-	struct xe_tile *tile = gt_to_tile(gt);
-	struct xe_device *xe = tile_to_xe(tile);
 	struct xe_guc *guc = &gt->uc.guc;
-	struct xe_bo *bo;
+	CLASS(xe_guc_buf, buf)(&guc->buf, ndwords);
 	int ret;
 
 	xe_gt_assert(gt, size % sizeof(u32) == 0);
 	xe_gt_assert(gt, size == ndwords * sizeof(u32));
 
-	bo = xe_bo_create_pin_map_novm(xe, tile,
-				       ALIGN(size, PAGE_SIZE),
-				       ttm_bo_type_kernel,
-				       XE_BO_FLAG_SYSTEM |
-				       XE_BO_FLAG_GGTT |
-				       XE_BO_FLAG_GGTT_INVALIDATE, false);
-	if (IS_ERR(bo))
-		return PTR_ERR(bo);
+	if (!xe_guc_buf_is_valid(buf))
+		return -ENOBUFS;
+
+	/* FW expects this buffer to be zero-initialized */
+	memset(xe_guc_buf_cpu_ptr(buf), 0, size);
 
 	ret = guc_action_vf_save_restore(guc, vfid, GUC_PF_OPCODE_VF_SAVE,
-					 xe_bo_ggtt_addr(bo), ndwords);
+					 xe_guc_buf_flush(buf), ndwords);
 	if (!ret)
 		ret = -ENODATA;
 	else if (ret > ndwords)
 		ret = -EPROTO;
 	else if (ret > 0)
-		xe_map_memcpy_from(xe, buff, &bo->vmap, 0, ret * sizeof(u32));
+		memcpy(dst, xe_guc_buf_sync_read(buf), ret * sizeof(u32));
 
-	xe_bo_unpin_map_no_vm(bo);
 	return ret;
 }
 
 /* Return: number of state dwords restored or a negative error code on failure */
 static int pf_send_guc_restore_vf_state(struct xe_gt *gt, unsigned int vfid,
-					const void *buff, size_t size)
+					const void *src, size_t size)
 {
 	const int ndwords = size / sizeof(u32);
-	struct xe_tile *tile = gt_to_tile(gt);
-	struct xe_device *xe = tile_to_xe(tile);
 	struct xe_guc *guc = &gt->uc.guc;
-	struct xe_bo *bo;
+	CLASS(xe_guc_buf_from_data, buf)(&guc->buf, src, size);
 	int ret;
 
 	xe_gt_assert(gt, size % sizeof(u32) == 0);
 	xe_gt_assert(gt, size == ndwords * sizeof(u32));
 
-	bo = xe_bo_create_pin_map_novm(xe, tile,
-				       ALIGN(size, PAGE_SIZE),
-				       ttm_bo_type_kernel,
-				       XE_BO_FLAG_SYSTEM |
-				       XE_BO_FLAG_GGTT |
-				       XE_BO_FLAG_GGTT_INVALIDATE, false);
-	if (IS_ERR(bo))
-		return PTR_ERR(bo);
-
-	xe_map_memcpy_to(xe, &bo->vmap, 0, buff, size);
+	if (!xe_guc_buf_is_valid(buf))
+		return -ENOBUFS;
 
 	ret = guc_action_vf_save_restore(guc, vfid, GUC_PF_OPCODE_VF_RESTORE,
-					 xe_bo_ggtt_addr(bo), ndwords);
+					 xe_guc_buf_flush(buf), ndwords);
 	if (!ret)
 		ret = -ENODATA;
 	else if (ret > ndwords)
 		ret = -EPROTO;
 
-	xe_bo_unpin_map_no_vm(bo);
 	return ret;
 }
 

drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.h

@@ -11,6 +11,9 @@
 struct xe_gt;
 struct xe_sriov_packet;
 
+/* TODO: get this information by querying GuC in the future */
+#define XE_GT_SRIOV_PF_MIGRATION_GUC_DATA_MAX_SIZE SZ_8M
+
 int xe_gt_sriov_pf_migration_init(struct xe_gt *gt);
 int xe_gt_sriov_pf_migration_save_guc_state(struct xe_gt *gt, unsigned int vfid);
 int xe_gt_sriov_pf_migration_restore_guc_state(struct xe_gt *gt, unsigned int vfid);

drivers/gpu/drm/xe/xe_guc.c

@@ -24,6 +24,7 @@
 #include "xe_gt_printk.h"
 #include "xe_gt_sriov_vf.h"
 #include "xe_gt_throttle.h"
+#include "xe_gt_sriov_pf_migration.h"
 #include "xe_guc_ads.h"
 #include "xe_guc_buf.h"
 #include "xe_guc_capture.h"
@@ -40,6 +41,7 @@
 #include "xe_mmio.h"
 #include "xe_platform_types.h"
 #include "xe_sriov.h"
+#include "xe_sriov_pf_migration.h"
 #include "xe_uc.h"
 #include "xe_uc_fw.h"
 #include "xe_wa.h"
@@ -821,6 +823,14 @@ static int vf_guc_init_post_hwconfig(struct xe_guc *guc)
 	return 0;
 }
 
+static u32 guc_additional_cache_size(struct xe_device *xe)
+{
+	if (IS_SRIOV_PF(xe) && xe_sriov_pf_migration_supported(xe))
+		return XE_GT_SRIOV_PF_MIGRATION_GUC_DATA_MAX_SIZE;
+	else
+		return 0; /* Fallback to default size */
+}
+
 /**
  * xe_guc_init_post_hwconfig - initialize GuC post hwconfig load
  * @guc: The GuC object
@@ -860,7 +870,8 @@ int xe_guc_init_post_hwconfig(struct xe_guc *guc)
 	if (ret)
 		return ret;
 
-	ret = xe_guc_buf_cache_init(&guc->buf);
+	ret = xe_guc_buf_cache_init_with_size(&guc->buf,
+					      guc_additional_cache_size(guc_to_xe(guc)));
 	if (ret)
 		return ret;