[PATCH v2 8/9] drm/xe/migrate: Introduce xe_migrate_reinit()

Raag Jadav
2026-02-27T17:03:45Z

In preparation of usecases which require re-initializing migrate context
after PCIe FLR, introduce xe_migrate_reinit() helper. Migrate exec queue
and pt_bo already exist in migrate structure but since their contents live
on VRAM, they are lost on PCIe FLR and need re-initialization.

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
---
v2: Re-initialize migrate context (Matthew Brost)
---
drivers/gpu/drm/xe/xe_gt.c | 10 +++++
drivers/gpu/drm/xe/xe_migrate.c | 65 +++++++++++++++++++++++++--------
drivers/gpu/drm/xe/xe_migrate.h | 1 +
3 files changed, 61 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index ff4a4e769fb1..ab34312830e3 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -966,6 +966,16 @@ void xe_gt_flr_prepare(struct xe_gt *gt)
*/
int xe_gt_flr_done(struct xe_gt *gt)
{
+ int err;
+
+ if (xe_gt_is_main_type(gt)) {
+ struct xe_tile *tile = gt_to_tile(gt);
+
+ err = xe_migrate_reinit(tile->migrate);
+ if (err)
+ return err;
+ }
+
return xe_uc_flr_done(&gt->uc);
}

diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
index 333af7b57ae9..f4a2ad3ce601 100644
--- a/drivers/gpu/drm/xe/xe_migrate.c
+++ b/drivers/gpu/drm/xe/xe_migrate.c
@@ -184,19 +184,11 @@ static void xe_migrate_program_identity(struct xe_device *xe, struct xe_vm *vm,
xe_assert(xe, pos == vram_limit);
}

-static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
- struct xe_vm *vm, struct drm_exec *exec)
+static int xe_migrate_pt_bo_alloc(struct xe_tile *tile, struct xe_migrate *m,
+ struct xe_vm *vm, struct drm_exec *exec)
{
- struct xe_device *xe = tile_to_xe(tile);
- u16 pat_index = xe->pat.idx[XE_CACHE_WB];
- u8 id = tile->id;
- u32 num_entries = NUM_PT_SLOTS, num_level = vm->pt_root[id]->level;
-#define VRAM_IDENTITY_MAP_COUNT 2
- u32 num_setup = num_level + VRAM_IDENTITY_MAP_COUNT;
-#undef VRAM_IDENTITY_MAP_COUNT
- u32 map_ofs, level, i;
struct xe_bo *bo, *batch = tile->mem.kernel_bb_pool->bo;
- u64 entry, pt29_ofs;
+ u32 num_entries = NUM_PT_SLOTS;

/* Can't bump NUM_PT_SLOTS too high */
BUILD_BUG_ON(NUM_PT_SLOTS > SZ_2M/XE_PAGE_SIZE);
@@ -216,6 +208,24 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
if (IS_ERR(bo))
return PTR_ERR(bo);

+ m->pt_bo = bo;
+ return 0;
+}
+
+static void xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
+ struct xe_vm *vm, u32 *ofs)
+{
+ struct xe_device *xe = tile_to_xe(tile);
+ u16 pat_index = xe->pat.idx[XE_CACHE_WB];
+ u8 id = tile->id;
+ u32 num_entries = NUM_PT_SLOTS, num_level = vm->pt_root[id]->level;
+#define VRAM_IDENTITY_MAP_COUNT 2
+ u32 num_setup = num_level + VRAM_IDENTITY_MAP_COUNT;
+#undef VRAM_IDENTITY_MAP_COUNT
+ u32 map_ofs, level, i;
+ struct xe_bo *bo = m->pt_bo, *batch = tile->mem.kernel_bb_pool->bo;
+ u64 entry, pt29_ofs;
+
/* PT30 & PT31 reserved for 2M identity map */
pt29_ofs = xe_bo_size(bo) - 3 * XE_PAGE_SIZE;
entry = vm->pt_ops->pde_encode_bo(bo, pt29_ofs);
@@ -338,6 +348,12 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
}
}

+ if (ofs)
+ *ofs = map_ofs;
+}
+
+static void xe_migrate_suballoc_manager_init(struct xe_migrate *m, u32 map_ofs)
+{
/*
* Example layout created above, with root level = 3:
* [PT0...PT7]: kernel PT's for copy/clear; 64 or 4KiB PTE's
@@ -363,9 +379,6 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
drm_suballoc_manager_init(&m->vm_update_sa,
(size_t)(map_ofs / XE_PAGE_SIZE - NUM_KERNEL_PDE) *
NUM_VMUSA_UNIT_PER_PAGE, 0);
-
- m->pt_bo = bo;
- return 0;
}

/*
@@ -416,12 +429,22 @@ static int xe_migrate_lock_prepare_vm(struct xe_tile *tile, struct xe_migrate *m
struct xe_device *xe = tile_to_xe(tile);
struct xe_validation_ctx ctx;
struct drm_exec exec;
+ u32 map_ofs;
int err = 0;

xe_validation_guard(&ctx, &xe->val, &exec, (struct xe_val_flags) {}, err) {
err = xe_vm_drm_exec_lock(vm, &exec);
+ if (err)
+ return err;
+
drm_exec_retry_on_contention(&exec);
- err = xe_migrate_prepare_vm(tile, m, vm, &exec);
+
+ err = xe_migrate_pt_bo_alloc(tile, m, vm, &exec);
+ if (err)
+ return err;
+
+ xe_migrate_prepare_vm(tile, m, vm, &map_ofs);
+ xe_migrate_suballoc_manager_init(m, map_ofs);
drm_exec_retry_on_contention(&exec);
xe_validation_retry_on_oom(&ctx, &err);
}
@@ -429,6 +452,18 @@ static int xe_migrate_lock_prepare_vm(struct xe_tile *tile, struct xe_migrate *m
return err;
}

+/**
+ * xe_migrate_reinit() - Re-initialize a migrate context
+ * @m: The migration context
+ *
+ * Returns: 0 on success, negative error code otherwise.
+ */
+int xe_migrate_reinit(struct xe_migrate *m)
+{
+ xe_migrate_prepare_vm(m->tile, m, m->q->vm, NULL);
+ return xe_exec_queue_reinit(m->q);
+}
+
/**
* xe_migrate_init() - Initialize a migrate context
* @m: The migration context
diff --git a/drivers/gpu/drm/xe/xe_migrate.h b/drivers/gpu/drm/xe/xe_migrate.h
index 1522afb37dcf..fffbcab8b2e3 100644
--- a/drivers/gpu/drm/xe/xe_migrate.h
+++ b/drivers/gpu/drm/xe/xe_migrate.h
@@ -112,6 +112,7 @@ struct xe_migrate_pt_update {

struct xe_migrate *xe_migrate_alloc(struct xe_tile *tile);
int xe_migrate_init(struct xe_migrate *m);
+int xe_migrate_reinit(struct xe_migrate *m);

struct dma_fence *xe_migrate_to_vram(struct xe_migrate *m,
unsigned long npages,
--
2.43.0