[PATCH v2 2/5] drm/xe: Start using ggtt->start in preparation of balloon removal
Summers, Stuart
stuart.summers at intel.com
Wed Jun 11 18:53:11 UTC 2025
On Tue, 2025-06-10 at 09:02 +0200, Maarten Lankhorst wrote:
> Instead of having ggtt->size point to the end of ggtt, have ggtt-
> >size
> be the actual size of the GGTT, and introduce ggtt->start to point to
> the beginning of GGTT.
>
> This will allow a massive cleanup of GGTT in case of SRIOV-VF.
>
> Signed-off-by: Maarten Lankhorst <dev at lankhorst.se>
Reviewed-by: Stuart Summers <stuart.summers at intel.com>
I agree this is way better. Thanks for the patch!
> ---
> drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c | 2 +-
> drivers/gpu/drm/xe/xe_ggtt.c | 60 ++++++++++---------
> --
> drivers/gpu/drm/xe/xe_ggtt_types.h | 4 +-
> 3 files changed, 34 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c
> b/drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c
> index 537766cdd882e..12a8970a5ca1c 100644
> --- a/drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c
> +++ b/drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c
> @@ -67,7 +67,7 @@ static int guc_buf_test_init(struct kunit *test)
>
> KUNIT_ASSERT_EQ(test, 0,
> xe_ggtt_init_kunit(ggtt, DUT_GGTT_START,
> - DUT_GGTT_START +
> DUT_GGTT_SIZE));
> + DUT_GGTT_SIZE));
>
> kunit_activate_static_stub(test,
> xe_managed_bo_create_pin_map,
>
> replacement_xe_managed_bo_create_pin_map);
> diff --git a/drivers/gpu/drm/xe/xe_ggtt.c
> b/drivers/gpu/drm/xe/xe_ggtt.c
> index 7b11fa1356f0b..937cff3d44811 100644
> --- a/drivers/gpu/drm/xe/xe_ggtt.c
> +++ b/drivers/gpu/drm/xe/xe_ggtt.c
> @@ -126,7 +126,7 @@ static void ggtt_update_access_counter(struct
> xe_ggtt *ggtt)
> static void xe_ggtt_set_pte(struct xe_ggtt *ggtt, u64 addr, u64 pte)
> {
> xe_tile_assert(ggtt->tile, !(addr & XE_PTE_MASK));
> - xe_tile_assert(ggtt->tile, addr < ggtt->size);
> + xe_tile_assert(ggtt->tile, addr < ggtt->start + ggtt->size);
>
> writeq(pte, &ggtt->gsm[addr >> XE_PTE_SHIFT]);
> }
> @@ -222,18 +222,18 @@ static const struct xe_ggtt_pt_ops
> xelpg_pt_wa_ops = {
> .ggtt_set_pte = xe_ggtt_set_pte_and_flush,
> };
>
> -static void __xe_ggtt_init_early(struct xe_ggtt *ggtt, u32 reserved)
> +static void __xe_ggtt_init_early(struct xe_ggtt *ggtt, u64 start,
> u64 size)
> {
> - drm_mm_init(&ggtt->mm, reserved,
> - ggtt->size - reserved);
> + ggtt->start = start;
> + ggtt->size = size;
> + drm_mm_init(&ggtt->mm, start, ggtt->size);
> mutex_init(&ggtt->lock);
> primelockdep(ggtt);
> }
>
> -int xe_ggtt_init_kunit(struct xe_ggtt *ggtt, u32 reserved, u32 size)
> +int xe_ggtt_init_kunit(struct xe_ggtt *ggtt, u32 start, u32 size)
> {
> - ggtt->size = size;
> - __xe_ggtt_init_early(ggtt, reserved);
> + __xe_ggtt_init_early(ggtt, start, size);
> return 0;
> }
> EXPORT_SYMBOL_IF_KUNIT(xe_ggtt_init_kunit);
> @@ -254,26 +254,32 @@ 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;
> int err;
>
> - if (IS_SRIOV_VF(xe) || 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) {
> - drm_err(&xe->drm, "Hardware reported no preallocated
> GSM\n");
> - return -ENOMEM;
> + 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) {
> + drm_err(&xe->drm, "Hardware reported no
> preallocated GSM\n");
> + return -ENOMEM;
> + }
> + ggtt_start = wopcm;
> + ggtt_size = (gsm_size / 8) * (u64) XE_PAGE_SIZE -
> ggtt_start;
> + } else {
> + /* GGTT is expected to be 4GiB */
> + ggtt_start = wopcm;
> + ggtt_size = SZ_4G - ggtt_start;
> }
>
> ggtt->gsm = ggtt->tile->mmio.regs + SZ_8M;
> - ggtt->size = (gsm_size / 8) * (u64) XE_PAGE_SIZE;
> -
> if (IS_DGFX(xe) && xe->info.vram_flags &
> XE_VRAM_FLAGS_NEED64K)
> ggtt->flags |= XE_GGTT_FLAGS_64K;
>
> - if (ggtt->size > GUC_GGTT_TOP)
> - ggtt->size = GUC_GGTT_TOP;
> + 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 &&
> @@ -284,7 +290,7 @@ int xe_ggtt_init_early(struct xe_ggtt *ggtt)
> ggtt->pt_ops = &xelp_pt_ops;
>
> ggtt->wq = alloc_workqueue("xe-ggtt-wq", 0, WQ_MEM_RECLAIM);
> - __xe_ggtt_init_early(ggtt, xe_wopcm_size(xe));
> + __xe_ggtt_init_early(ggtt, ggtt_start, ggtt_size);
>
> err = drmm_add_action_or_reset(&xe->drm, ggtt_fini_early,
> ggtt);
> if (err)
> @@ -520,11 +526,9 @@ void xe_ggtt_node_remove_balloon_locked(struct
> xe_ggtt_node *node)
> static void xe_ggtt_assert_fit(struct xe_ggtt *ggtt, u64 start, u64
> size)
> {
> struct xe_tile *tile = ggtt->tile;
> - struct xe_device *xe = tile_to_xe(tile);
> - u64 __maybe_unused wopcm = xe_wopcm_size(xe);
>
> - xe_tile_assert(tile, start >= wopcm);
> - xe_tile_assert(tile, start + size < ggtt->size - wopcm);
> + xe_tile_assert(tile, start >= ggtt->start);
> + xe_tile_assert(tile, start + size <= ggtt->start + ggtt-
> >size);
> }
>
> /**
> @@ -830,14 +834,12 @@ u64 xe_ggtt_largest_hole(struct xe_ggtt *ggtt,
> u64 alignment, u64 *spare)
> {
> const struct drm_mm *mm = &ggtt->mm;
> const struct drm_mm_node *entry;
> - u64 hole_min_start = xe_wopcm_size(tile_to_xe(ggtt->tile));
> u64 hole_start, hole_end, hole_size;
> u64 max_hole = 0;
>
> mutex_lock(&ggtt->lock);
> -
> drm_mm_for_each_hole(entry, mm, hole_start, hole_end) {
> - hole_start = max(hole_start, hole_min_start);
> + hole_start = max(hole_start, ggtt->start);
> hole_start = ALIGN(hole_start, alignment);
> hole_end = ALIGN_DOWN(hole_end, alignment);
> if (hole_start >= hole_end)
> @@ -930,15 +932,13 @@ u64 xe_ggtt_print_holes(struct xe_ggtt *ggtt,
> u64 alignment, struct drm_printer
> {
> const struct drm_mm *mm = &ggtt->mm;
> const struct drm_mm_node *entry;
> - u64 hole_min_start = xe_wopcm_size(tile_to_xe(ggtt->tile));
> u64 hole_start, hole_end, hole_size;
> u64 total = 0;
> char buf[10];
>
> mutex_lock(&ggtt->lock);
> -
> drm_mm_for_each_hole(entry, mm, hole_start, hole_end) {
> - hole_start = max(hole_start, hole_min_start);
> + hole_start = max(hole_start, ggtt->start);
> hole_start = ALIGN(hole_start, alignment);
> hole_end = ALIGN_DOWN(hole_end, alignment);
> if (hole_start >= hole_end)
> diff --git a/drivers/gpu/drm/xe/xe_ggtt_types.h
> b/drivers/gpu/drm/xe/xe_ggtt_types.h
> index c5e999d58ff2a..a27919302d6b2 100644
> --- a/drivers/gpu/drm/xe/xe_ggtt_types.h
> +++ b/drivers/gpu/drm/xe/xe_ggtt_types.h
> @@ -22,7 +22,9 @@ struct xe_gt;
> struct xe_ggtt {
> /** @tile: Back pointer to tile where this GGTT belongs */
> struct xe_tile *tile;
> - /** @size: Total size of this GGTT */
> + /** @start: Start offset of GGTT */
> + u64 start;
> + /** @size: Total usable size of this GGTT */
> u64 size;
>
> #define XE_GGTT_FLAGS_64K BIT(0)
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