[PATCH 12/26] drm/xe/pf: Increase PF GuC Buffer Cache size and use it for VF migration

Michał Winiarski
2025-10-11T19:41:12Z

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.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
---
drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c | 54 +++++++------------
drivers/gpu/drm/xe/xe_guc.c | 2 +-
2 files changed, 20 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c
index 50f09994e2854..8b96eff8df93b 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c
+++ b/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_pf_migration.h"
@@ -57,73 +57,57 @@ 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;
+
+ 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);
- if (!ret)
+ xe_guc_buf_flush(buf), ndwords);
+ if (!ret) {
ret = -ENODATA;
- else if (ret > ndwords)
+ } else if (ret > ndwords) {
ret = -EPROTO;
- else if (ret > 0)
- xe_map_memcpy_from(xe, buff, &bo->vmap, 0, ret * sizeof(u32));
+ } else if (ret > 0) {
+ xe_guc_buf_sync(buf);
+ memcpy(dst, xe_guc_buf_cpu_ptr(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;
}

diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
index ccc7c60ae9b77..71ca06d1af62b 100644
--- a/drivers/gpu/drm/xe/xe_guc.c
+++ b/drivers/gpu/drm/xe/xe_guc.c
@@ -857,7 +857,7 @@ int xe_guc_init_post_hwconfig(struct xe_guc *guc)
if (ret)
return ret;

- ret = xe_guc_buf_cache_init(&guc->buf, SZ_8K);
+ ret = xe_guc_buf_cache_init(&guc->buf, IS_SRIOV_PF(guc_to_xe(guc)) ? SZ_8M : SZ_8K);
if (ret)
return ret;

--
2.50.1