[CI 1/4] drm/i915/ttm: make eviction mappable aware

[CI 1/4] drm/i915/ttm: make eviction mappable aware

[Matthew Auld]

If we need to make room for some mappable object, then we should
only victimize objects that have one or pages that occupy the visible
portion of LMEM. Let's also create a new priority hint for objects that
are placed in mappable memory, where we know that CPU access was
requested, that way we hopefully victimize these last.

v2(Thomas): s/TTM_PL_PRIV/I915_PL_LMEM0/

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 65 ++++++++++++++++++++++++-
 1 file changed, 63 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index a13e0204a139..3c2f044b9c6b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -7,8 +7,10 @@
 
 #include <drm/ttm/ttm_bo_driver.h>
 #include <drm/ttm/ttm_placement.h>
+#include <drm/drm_buddy.h>
 
 #include "i915_drv.h"
+#include "i915_ttm_buddy_manager.h"
 #include "intel_memory_region.h"
 #include "intel_region_ttm.h"
 
@@ -22,6 +24,7 @@
 #define I915_TTM_PRIO_PURGE     0
 #define I915_TTM_PRIO_NO_PAGES  1
 #define I915_TTM_PRIO_HAS_PAGES 2
+#define I915_TTM_PRIO_NEEDS_CPU_ACCESS 3
 
 /*
  * Size of struct ttm_place vector in on-stack struct ttm_placement allocs
@@ -339,6 +342,7 @@ static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
 				       const struct ttm_place *place)
 {
 	struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
+	struct ttm_resource *res = bo->resource;
 
 	if (!obj)
 		return false;
@@ -352,7 +356,48 @@ static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
 		return false;
 
 	/* Will do for now. Our pinned objects are still on TTM's LRU lists */
-	return i915_gem_object_evictable(obj);
+	if (!i915_gem_object_evictable(obj))
+		return false;
+
+	switch (res->mem_type) {
+	case I915_PL_LMEM0: {
+		struct ttm_resource_manager *man =
+			ttm_manager_type(bo->bdev, res->mem_type);
+		struct i915_ttm_buddy_resource *bman_res =
+			to_ttm_buddy_resource(res);
+		struct drm_buddy *mm = bman_res->mm;
+		struct drm_buddy_block *block;
+
+		if (!place->fpfn && !place->lpfn)
+			return true;
+
+		GEM_BUG_ON(!place->lpfn);
+
+		/*
+		 * If we just want something mappable then we can quickly check
+		 * if the current victim resource is using any of the CPU
+		 * visible portion.
+		 */
+		if (!place->fpfn &&
+		    place->lpfn == i915_ttm_buddy_man_visible_size(man))
+			return bman_res->used_visible_size > 0;
+
+		/* Real range allocation */
+		list_for_each_entry(block, &bman_res->blocks, link) {
+			unsigned long fpfn =
+				drm_buddy_block_offset(block) >> PAGE_SHIFT;
+			unsigned long lpfn = fpfn +
+				(drm_buddy_block_size(mm, block) >> PAGE_SHIFT);
+
+			if (place->fpfn < lpfn && place->lpfn > fpfn)
+				return true;
+		}
+		return false;
+	} default:
+		break;
+	}
+
+	return true;
 }
 
 static void i915_ttm_evict_flags(struct ttm_buffer_object *bo,
@@ -852,7 +897,23 @@ void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj)
 	} else if (!i915_gem_object_has_pages(obj)) {
 		bo->priority = I915_TTM_PRIO_NO_PAGES;
 	} else {
-		bo->priority = I915_TTM_PRIO_HAS_PAGES;
+		struct ttm_resource_manager *man =
+			ttm_manager_type(bo->bdev, bo->resource->mem_type);
+
+		/*
+		 * If we need to place an LMEM resource which doesn't need CPU
+		 * access then we should try not to victimize mappable objects
+		 * first, since we likely end up stealing more of the mappable
+		 * portion. And likewise when we try to find space for a mappble
+		 * object, we know not to ever victimize objects that don't
+		 * occupy any mappable pages.
+		 */
+		if (i915_ttm_cpu_maps_iomem(bo->resource) &&
+		    i915_ttm_buddy_man_visible_size(man) < man->size &&
+		    !(obj->flags & I915_BO_ALLOC_GPU_ONLY))
+			bo->priority = I915_TTM_PRIO_NEEDS_CPU_ACCESS;
+		else
+			bo->priority = I915_TTM_PRIO_HAS_PAGES;
 	}
 
 	ttm_bo_move_to_lru_tail(bo, bo->resource, NULL);
-- 
2.34.1

[CI 2/4] drm/i915/ttm: mappable migration on fault

[Matthew Auld]

The end goal is to have userspace tell the kernel what buffers will
require CPU access, however if we ever reach the CPU fault handler, and
the current resource is not mappable, then we should attempt to migrate
the buffer to the mappable portion of LMEM, or even system memory, if the
allowable placements permit it.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 54 ++++++++++++++++++++++---
 1 file changed, 48 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 3c2f044b9c6b..45cc5837ce00 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -638,11 +638,24 @@ static void i915_ttm_swap_notify(struct ttm_buffer_object *bo)
 		i915_ttm_purge(obj);
 }
 
+static bool i915_ttm_resource_mappable(struct ttm_resource *res)
+{
+	struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res);
+
+	if (!i915_ttm_cpu_maps_iomem(res))
+		return true;
+
+	return bman_res->used_visible_size == bman_res->base.num_pages;
+}
+
 static int i915_ttm_io_mem_reserve(struct ttm_device *bdev, struct ttm_resource *mem)
 {
 	if (!i915_ttm_cpu_maps_iomem(mem))
 		return 0;
 
+	if (!i915_ttm_resource_mappable(mem))
+		return -EINVAL;
+
 	mem->bus.caching = ttm_write_combined;
 	mem->bus.is_iomem = true;
 
@@ -781,14 +794,15 @@ static int i915_ttm_get_pages(struct drm_i915_gem_object *obj)
  * Gem forced migration using the i915_ttm_migrate() op, is allowed even
  * to regions that are not in the object's list of allowable placements.
  */
-static int i915_ttm_migrate(struct drm_i915_gem_object *obj,
-			    struct intel_memory_region *mr)
+static int __i915_ttm_migrate(struct drm_i915_gem_object *obj,
+			      struct intel_memory_region *mr,
+			      unsigned int flags)
 {
 	struct ttm_place requested;
 	struct ttm_placement placement;
 	int ret;
 
-	i915_ttm_place_from_region(mr, &requested, obj->flags);
+	i915_ttm_place_from_region(mr, &requested, flags);
 	placement.num_placement = 1;
 	placement.num_busy_placement = 1;
 	placement.placement = &requested;
@@ -811,6 +825,12 @@ static int i915_ttm_migrate(struct drm_i915_gem_object *obj,
 	return 0;
 }
 
+static int i915_ttm_migrate(struct drm_i915_gem_object *obj,
+			    struct intel_memory_region *mr)
+{
+	return __i915_ttm_migrate(obj, mr, obj->flags);
+}
+
 static void i915_ttm_put_pages(struct drm_i915_gem_object *obj,
 			       struct sg_table *st)
 {
@@ -955,9 +975,6 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
 	if (!obj)
 		return VM_FAULT_SIGBUS;
 
-	if (obj->flags & I915_BO_ALLOC_GPU_ONLY)
-		return -EINVAL;
-
 	/* Sanity check that we allow writing into this object */
 	if (unlikely(i915_gem_object_is_readonly(obj) &&
 		     area->vm_flags & VM_WRITE))
@@ -972,6 +989,31 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
 		return VM_FAULT_SIGBUS;
 	}
 
+	if (!i915_ttm_resource_mappable(bo->resource)) {
+		int err = -ENODEV;
+		int i;
+
+		for (i = 0; i < obj->mm.n_placements; i++) {
+			struct intel_memory_region *mr = obj->mm.placements[i];
+			unsigned int flags;
+
+			if (!mr->io_size && mr->type != INTEL_MEMORY_SYSTEM)
+				continue;
+
+			flags = obj->flags;
+			flags &= ~I915_BO_ALLOC_GPU_ONLY;
+			err = __i915_ttm_migrate(obj, mr, flags);
+			if (!err)
+				break;
+		}
+
+		if (err) {
+			drm_dbg(dev, "Unable to make resource CPU accessible\n");
+			dma_resv_unlock(bo->base.resv);
+			return VM_FAULT_SIGBUS;
+		}
+	}
+
 	if (drm_dev_enter(dev, &idx)) {
 		ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
 					       TTM_BO_VM_NUM_PREFAULT);
-- 
2.34.1

[CI 3/4] drm/i915/selftests: handle allocation failures

[Matthew Auld]

If we have to contend with non-mappable LMEM, then we need to ensure the
object fits within the mappable portion, like in the selftests, where we
later try to CPU access the pages. However if it can't then we need to
gracefully handle this, without throwing an error.

Also it looks like TTM will return -ENOMEM, in ttm_bo_mem_space() after
exhausting all possible placements.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Acked-by: Nirmoy Das <nirmoy.das@intel.com>
---
 drivers/gpu/drm/i915/gem/selftests/huge_pages.c      | 2 +-
 drivers/gpu/drm/i915/selftests/intel_memory_region.c | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
index dbbae53f820a..7a84fa68a99c 100644
--- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
@@ -1345,7 +1345,7 @@ static int igt_ppgtt_smoke_huge(void *arg)
 
 		err = i915_gem_object_pin_pages_unlocked(obj);
 		if (err) {
-			if (err == -ENXIO || err == -E2BIG) {
+			if (err == -ENXIO || err == -E2BIG || err == -ENOMEM) {
 				i915_gem_object_put(obj);
 				size >>= 1;
 				goto try_again;
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index 56dec9723601..ba32893e0873 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -822,8 +822,14 @@ static int igt_lmem_create_with_ps(void *arg)
 
 		i915_gem_object_lock(obj, NULL);
 		err = i915_gem_object_pin_pages(obj);
-		if (err)
+		if (err) {
+			if (err == -ENXIO || err == -E2BIG || err == -ENOMEM) {
+				pr_info("%s not enough lmem for ps(%u) err=%d\n",
+					__func__, ps, err);
+				err = 0;
+			}
 			goto out_put;
+		}
 
 		daddr = i915_gem_object_get_dma_address(obj, 0);
 		if (!IS_ALIGNED(daddr, ps)) {
-- 
2.34.1

[CI 4/4] drm/i915/selftests: exercise mmap migration

[Matthew Auld]

Exercise each of the migration scenarios, verifying that the final
placement and buffer contents match our expectations.

v2(Thomas): Replace for_i915_gem_ww() block with simpler object_lock()

v3:
- For testing purposes allow forcing the io_size such that we can
  exercise the allocation + migration path on devices that don't have the
  small BAR limit.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 .../drm/i915/gem/selftests/i915_gem_mman.c    | 329 ++++++++++++++++++
 drivers/gpu/drm/i915/i915_ttm_buddy_manager.c |  10 +
 drivers/gpu/drm/i915/i915_ttm_buddy_manager.h |   5 +
 3 files changed, 344 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
index 8ae1a1530bd8..c1b1147479c8 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
@@ -8,10 +8,13 @@
 
 #include "gem/i915_gem_internal.h"
 #include "gem/i915_gem_region.h"
+#include "gem/i915_gem_ttm.h"
 #include "gt/intel_engine_pm.h"
 #include "gt/intel_gpu_commands.h"
 #include "gt/intel_gt.h"
 #include "gt/intel_gt_pm.h"
+#include "gt/intel_migrate.h"
+#include "i915_ttm_buddy_manager.h"
 
 #include "huge_gem_object.h"
 #include "i915_selftest.h"
@@ -1001,6 +1004,331 @@ static int igt_mmap(void *arg)
 	return 0;
 }
 
+static void igt_close_objects(struct drm_i915_private *i915,
+			      struct list_head *objects)
+{
+	struct drm_i915_gem_object *obj, *on;
+
+	list_for_each_entry_safe(obj, on, objects, st_link) {
+		i915_gem_object_lock(obj, NULL);
+		if (i915_gem_object_has_pinned_pages(obj))
+			i915_gem_object_unpin_pages(obj);
+		/* No polluting the memory region between tests */
+		__i915_gem_object_put_pages(obj);
+		i915_gem_object_unlock(obj);
+		list_del(&obj->st_link);
+		i915_gem_object_put(obj);
+	}
+
+	cond_resched();
+
+	i915_gem_drain_freed_objects(i915);
+}
+
+static void igt_make_evictable(struct list_head *objects)
+{
+	struct drm_i915_gem_object *obj;
+
+	list_for_each_entry(obj, objects, st_link) {
+		i915_gem_object_lock(obj, NULL);
+		if (i915_gem_object_has_pinned_pages(obj))
+			i915_gem_object_unpin_pages(obj);
+		i915_gem_object_unlock(obj);
+	}
+
+	cond_resched();
+}
+
+static int igt_fill_mappable(struct intel_memory_region *mr,
+			     struct list_head *objects)
+{
+	u64 size, total;
+	int err;
+
+	total = 0;
+	size = mr->io_size;
+	do {
+		struct drm_i915_gem_object *obj;
+
+		obj = i915_gem_object_create_region(mr, size, 0, 0);
+		if (IS_ERR(obj)) {
+			err = PTR_ERR(obj);
+			goto err_close;
+		}
+
+		list_add(&obj->st_link, objects);
+
+		err = i915_gem_object_pin_pages_unlocked(obj);
+		if (err) {
+			if (err != -ENXIO && err != -ENOMEM)
+				goto err_close;
+
+			if (size == mr->min_page_size) {
+				err = 0;
+				break;
+			}
+
+			size >>= 1;
+			continue;
+		}
+
+		total += obj->base.size;
+	} while (1);
+
+	pr_info("%s filled=%lluMiB\n", __func__, total >> 20);
+	return 0;
+
+err_close:
+	igt_close_objects(mr->i915, objects);
+	return err;
+}
+
+static int ___igt_mmap_migrate(struct drm_i915_private *i915,
+			       struct drm_i915_gem_object *obj,
+			       unsigned long addr,
+			       bool unfaultable)
+{
+	struct vm_area_struct *area;
+	int err = 0, i;
+
+	pr_info("igt_mmap(%s, %d) @ %lx\n",
+		obj->mm.region->name, I915_MMAP_TYPE_FIXED, addr);
+
+	mmap_read_lock(current->mm);
+	area = vma_lookup(current->mm, addr);
+	mmap_read_unlock(current->mm);
+	if (!area) {
+		pr_err("%s: Did not create a vm_area_struct for the mmap\n",
+		       obj->mm.region->name);
+		err = -EINVAL;
+		goto out_unmap;
+	}
+
+	for (i = 0; i < obj->base.size / sizeof(u32); i++) {
+		u32 __user *ux = u64_to_user_ptr((u64)(addr + i * sizeof(*ux)));
+		u32 x;
+
+		if (get_user(x, ux)) {
+			err = -EFAULT;
+			if (!unfaultable) {
+				pr_err("%s: Unable to read from mmap, offset:%zd\n",
+				       obj->mm.region->name, i * sizeof(x));
+				goto out_unmap;
+			}
+
+			continue;
+		}
+
+		if (unfaultable) {
+			pr_err("%s: Faulted unmappable memory\n",
+			       obj->mm.region->name);
+			err = -EINVAL;
+			goto out_unmap;
+		}
+
+		if (x != expand32(POISON_INUSE)) {
+			pr_err("%s: Read incorrect value from mmap, offset:%zd, found:%x, expected:%x\n",
+			       obj->mm.region->name,
+			       i * sizeof(x), x, expand32(POISON_INUSE));
+			err = -EINVAL;
+			goto out_unmap;
+		}
+
+		x = expand32(POISON_FREE);
+		if (put_user(x, ux)) {
+			pr_err("%s: Unable to write to mmap, offset:%zd\n",
+			       obj->mm.region->name, i * sizeof(x));
+			err = -EFAULT;
+			goto out_unmap;
+		}
+	}
+
+	if (unfaultable) {
+		if (err == -EFAULT)
+			err = 0;
+	} else {
+		obj->flags &= ~I915_BO_ALLOC_GPU_ONLY;
+		err = wc_check(obj);
+	}
+out_unmap:
+	vm_munmap(addr, obj->base.size);
+	return err;
+}
+
+#define IGT_MMAP_MIGRATE_TOPDOWN     (1 << 0)
+#define IGT_MMAP_MIGRATE_FILL        (1 << 1)
+#define IGT_MMAP_MIGRATE_EVICTABLE   (1 << 2)
+#define IGT_MMAP_MIGRATE_UNFAULTABLE (1 << 3)
+static int __igt_mmap_migrate(struct intel_memory_region **placements,
+			      int n_placements,
+			      struct intel_memory_region *expected_mr,
+			      unsigned int flags)
+{
+	struct drm_i915_private *i915 = placements[0]->i915;
+	struct drm_i915_gem_object *obj;
+	struct i915_request *rq = NULL;
+	unsigned long addr;
+	LIST_HEAD(objects);
+	u64 offset;
+	int err;
+
+	obj = __i915_gem_object_create_user(i915, PAGE_SIZE,
+					    placements,
+					    n_placements);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	if (flags & IGT_MMAP_MIGRATE_TOPDOWN)
+		obj->flags |= I915_BO_ALLOC_GPU_ONLY;
+
+	err = __assign_mmap_offset(obj, I915_MMAP_TYPE_FIXED, &offset, NULL);
+	if (err)
+		goto out_put;
+
+	/*
+	 * This will eventually create a GEM context, due to opening dummy drm
+	 * file, which needs a tiny amount of mappable device memory for the top
+	 * level paging structures(and perhaps scratch), so make sure we
+	 * allocate early, to avoid tears.
+	 */
+	addr = igt_mmap_offset(i915, offset, obj->base.size,
+			       PROT_WRITE, MAP_SHARED);
+	if (IS_ERR_VALUE(addr)) {
+		err = addr;
+		goto out_put;
+	}
+
+	if (flags & IGT_MMAP_MIGRATE_FILL) {
+		err = igt_fill_mappable(placements[0], &objects);
+		if (err)
+			goto out_put;
+	}
+
+	err = i915_gem_object_lock(obj, NULL);
+	if (err)
+		goto out_put;
+
+	err = i915_gem_object_pin_pages(obj);
+	if (err) {
+		i915_gem_object_unlock(obj);
+		goto out_put;
+	}
+
+	err = intel_context_migrate_clear(to_gt(i915)->migrate.context, NULL,
+					  obj->mm.pages->sgl, obj->cache_level,
+					  i915_gem_object_is_lmem(obj),
+					  expand32(POISON_INUSE), &rq);
+	i915_gem_object_unpin_pages(obj);
+	if (rq) {
+		dma_resv_add_excl_fence(obj->base.resv, &rq->fence);
+		i915_gem_object_set_moving_fence(obj, &rq->fence);
+		i915_request_put(rq);
+	}
+	i915_gem_object_unlock(obj);
+	if (err)
+		goto out_put;
+
+	if (flags & IGT_MMAP_MIGRATE_EVICTABLE)
+		igt_make_evictable(&objects);
+
+	err = ___igt_mmap_migrate(i915, obj, addr,
+				  flags & IGT_MMAP_MIGRATE_UNFAULTABLE);
+	if (!err && obj->mm.region != expected_mr) {
+		pr_err("%s region mismatch %s\n", __func__, expected_mr->name);
+		err = -EINVAL;
+	}
+
+out_put:
+	i915_gem_object_put(obj);
+	igt_close_objects(i915, &objects);
+	return err;
+}
+
+static int igt_mmap_migrate(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct intel_memory_region *system = i915->mm.regions[INTEL_REGION_SMEM];
+	struct intel_memory_region *mr;
+	enum intel_region_id id;
+
+	for_each_memory_region(mr, i915, id) {
+		struct intel_memory_region *mixed[] = { mr, system };
+		struct intel_memory_region *single[] = { mr };
+		struct ttm_resource_manager *man = mr->region_private;
+		resource_size_t saved_io_size;
+		int err;
+
+		if (mr->private)
+			continue;
+
+		if (!mr->io_size)
+			continue;
+
+		/*
+		 * For testing purposes let's force small BAR, if not already
+		 * present.
+		 */
+		saved_io_size = mr->io_size;
+		if (mr->io_size == mr->total) {
+			resource_size_t io_size = mr->io_size;
+
+			io_size = rounddown_pow_of_two(io_size >> 1);
+			if (io_size < PAGE_SIZE)
+				continue;
+
+			mr->io_size = io_size;
+			i915_ttm_buddy_man_force_visible_size(man,
+							      io_size >> PAGE_SHIFT);
+		}
+
+		/*
+		 * Allocate in the mappable portion, should be no suprises here.
+		 */
+		err = __igt_mmap_migrate(mixed, ARRAY_SIZE(mixed), mr, 0);
+		if (err)
+			goto out_io_size;
+
+		/*
+		 * Allocate in the non-mappable portion, but force migrating to
+		 * the mappable portion on fault (LMEM -> LMEM)
+		 */
+		err = __igt_mmap_migrate(single, ARRAY_SIZE(single), mr,
+					 IGT_MMAP_MIGRATE_TOPDOWN |
+					 IGT_MMAP_MIGRATE_FILL |
+					 IGT_MMAP_MIGRATE_EVICTABLE);
+		if (err)
+			goto out_io_size;
+
+		/*
+		 * Allocate in the non-mappable portion, but force spilling into
+		 * system memory on fault (LMEM -> SMEM)
+		 */
+		err = __igt_mmap_migrate(mixed, ARRAY_SIZE(mixed), system,
+					 IGT_MMAP_MIGRATE_TOPDOWN |
+					 IGT_MMAP_MIGRATE_FILL);
+		if (err)
+			goto out_io_size;
+
+		/*
+		 * Allocate in the non-mappable portion, but since the mappable
+		 * portion is already full, and we can't spill to system memory,
+		 * then we should expect the fault to fail.
+		 */
+		err = __igt_mmap_migrate(single, ARRAY_SIZE(single), mr,
+					 IGT_MMAP_MIGRATE_TOPDOWN |
+					 IGT_MMAP_MIGRATE_FILL |
+					 IGT_MMAP_MIGRATE_UNFAULTABLE);
+out_io_size:
+		mr->io_size = saved_io_size;
+		i915_ttm_buddy_man_force_visible_size(man,
+						      mr->io_size >> PAGE_SHIFT);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
 static const char *repr_mmap_type(enum i915_mmap_type type)
 {
 	switch (type) {
@@ -1426,6 +1754,7 @@ int i915_gem_mman_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(igt_smoke_tiling),
 		SUBTEST(igt_mmap_offset_exhaustion),
 		SUBTEST(igt_mmap),
+		SUBTEST(igt_mmap_migrate),
 		SUBTEST(igt_mmap_access),
 		SUBTEST(igt_mmap_revoke),
 		SUBTEST(igt_mmap_gpu),
diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
index 92d49a3c378c..129f668f21ff 100644
--- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
+++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
@@ -362,3 +362,13 @@ u64 i915_ttm_buddy_man_visible_size(struct ttm_resource_manager *man)
 
 	return bman->visible_size;
 }
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+void i915_ttm_buddy_man_force_visible_size(struct ttm_resource_manager *man,
+					   u64 size)
+{
+	struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
+
+	bman->visible_size = size;
+}
+#endif
diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
index 35fe03a6a78c..52d9586d242c 100644
--- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
+++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
@@ -61,4 +61,9 @@ int i915_ttm_buddy_man_reserve(struct ttm_resource_manager *man,
 
 u64 i915_ttm_buddy_man_visible_size(struct ttm_resource_manager *man);
 
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+void i915_ttm_buddy_man_force_visible_size(struct ttm_resource_manager *man,
+					   u64 size);
+#endif
+
 #endif
-- 
2.34.1