[PATCH v4 2/5] drm/i915: enforce min GTT alignment for discrete cards

From: Robert Beckett
Date: Fri Jan 21 2022 - 14:52:01 EST


From: Matthew Auld <matthew.auld@xxxxxxxxx>

For local-memory objects we need to align the GTT addresses
to 64K, both for the ppgtt and ggtt.

We need to support vm->min_alignment > 4K, depending
on the vm itself and the type of object we are inserting.
With this in mind update the GTT selftests to take this
into account.

For compact-pt we further align and pad lmem object GTT addresses
to 2MB to ensure PDEs contain consistent page sizes as
required by the HW.

v3:
* use needs_compact_pt flag to discriminate between
64K and 64K with compact-pt
* add i915_vm_obj_min_alignment
* use i915_vm_obj_min_alignment to round up vma reservation
if compact-pt instead of hard coding

Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
Signed-off-by: Robert Beckett <bob.beckett@xxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
---
.../i915/gem/selftests/i915_gem_client_blt.c | 23 +++--
drivers/gpu/drm/i915/gt/intel_gtt.c | 12 +++
drivers/gpu/drm/i915/gt/intel_gtt.h | 15 +++
drivers/gpu/drm/i915/i915_vma.c | 9 ++
drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 96 ++++++++++++-------
5 files changed, 114 insertions(+), 41 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_client_blt.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_client_blt.c
index c8ff8bf0986d..f0bfce53258f 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_client_blt.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_client_blt.c
@@ -39,6 +39,7 @@ struct tiled_blits {
struct blit_buffer scratch;
struct i915_vma *batch;
u64 hole;
+ u64 align;
u32 width;
u32 height;
};
@@ -410,14 +411,21 @@ tiled_blits_create(struct intel_engine_cs *engine, struct rnd_state *prng)
goto err_free;
}

- hole_size = 2 * PAGE_ALIGN(WIDTH * HEIGHT * 4);
+ t->align = I915_GTT_PAGE_SIZE_2M; /* XXX worst case, derive from vm! */
+ t->align = max(t->align,
+ i915_vm_min_alignment(t->ce->vm, INTEL_MEMORY_LOCAL));
+ t->align = max(t->align,
+ i915_vm_min_alignment(t->ce->vm, INTEL_MEMORY_SYSTEM));
+
+ hole_size = 2 * round_up(WIDTH * HEIGHT * 4, t->align);
hole_size *= 2; /* room to maneuver */
- hole_size += 2 * I915_GTT_MIN_ALIGNMENT;
+ hole_size += 2 * t->align; /* padding on either side */

mutex_lock(&t->ce->vm->mutex);
memset(&hole, 0, sizeof(hole));
err = drm_mm_insert_node_in_range(&t->ce->vm->mm, &hole,
- hole_size, 0, I915_COLOR_UNEVICTABLE,
+ hole_size, t->align,
+ I915_COLOR_UNEVICTABLE,
0, U64_MAX,
DRM_MM_INSERT_BEST);
if (!err)
@@ -428,7 +436,7 @@ tiled_blits_create(struct intel_engine_cs *engine, struct rnd_state *prng)
goto err_put;
}

- t->hole = hole.start + I915_GTT_MIN_ALIGNMENT;
+ t->hole = hole.start + t->align;
pr_info("Using hole at %llx\n", t->hole);

err = tiled_blits_create_buffers(t, WIDTH, HEIGHT, prng);
@@ -455,7 +463,7 @@ static void tiled_blits_destroy(struct tiled_blits *t)
static int tiled_blits_prepare(struct tiled_blits *t,
struct rnd_state *prng)
{
- u64 offset = PAGE_ALIGN(t->width * t->height * 4);
+ u64 offset = round_up(t->width * t->height * 4, t->align);
u32 *map;
int err;
int i;
@@ -486,8 +494,7 @@ static int tiled_blits_prepare(struct tiled_blits *t,

static int tiled_blits_bounce(struct tiled_blits *t, struct rnd_state *prng)
{
- u64 offset =
- round_up(t->width * t->height * 4, 2 * I915_GTT_MIN_ALIGNMENT);
+ u64 offset = round_up(t->width * t->height * 4, 2 * t->align);
int err;

/* We want to check position invariant tiling across GTT eviction */
@@ -500,7 +507,7 @@ static int tiled_blits_bounce(struct tiled_blits *t, struct rnd_state *prng)

/* Reposition so that we overlap the old addresses, and slightly off */
err = tiled_blit(t,
- &t->buffers[2], t->hole + I915_GTT_MIN_ALIGNMENT,
+ &t->buffers[2], t->hole + t->align,
&t->buffers[1], t->hole + 3 * offset / 2);
if (err)
return err;
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
index 46be4197b93f..df23ebdfc994 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
@@ -223,6 +223,18 @@ void i915_address_space_init(struct i915_address_space *vm, int subclass)

GEM_BUG_ON(!vm->total);
drm_mm_init(&vm->mm, 0, vm->total);
+
+ memset64(vm->min_alignment, I915_GTT_MIN_ALIGNMENT,
+ ARRAY_SIZE(vm->min_alignment));
+
+ if (HAS_64K_PAGES(vm->i915) && NEEDS_COMPACT_PT(vm->i915)) {
+ vm->min_alignment[INTEL_MEMORY_LOCAL] = I915_GTT_PAGE_SIZE_2M;
+ vm->min_alignment[INTEL_MEMORY_STOLEN_LOCAL] = I915_GTT_PAGE_SIZE_2M;
+ } else if (HAS_64K_PAGES(vm->i915)) {
+ vm->min_alignment[INTEL_MEMORY_LOCAL] = I915_GTT_PAGE_SIZE_64K;
+ vm->min_alignment[INTEL_MEMORY_STOLEN_LOCAL] = I915_GTT_PAGE_SIZE_64K;
+ }
+
vm->mm.head_node.color = I915_COLOR_UNEVICTABLE;

INIT_LIST_HEAD(&vm->bound_list);
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index 8073438b67c8..1519c6a689b0 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -29,6 +29,8 @@
#include "i915_selftest.h"
#include "i915_vma_resource.h"
#include "i915_vma_types.h"
+#include "i915_params.h"
+#include "intel_memory_region.h"

#define I915_GFP_ALLOW_FAIL (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN)

@@ -223,6 +225,7 @@ struct i915_address_space {
struct device *dma;
u64 total; /* size addr space maps (ex. 2GB for ggtt) */
u64 reserved; /* size addr space reserved */
+ u64 min_alignment[INTEL_MEMORY_STOLEN_LOCAL + 1];

unsigned int bind_async_flags;

@@ -384,6 +387,18 @@ i915_vm_has_scratch_64K(struct i915_address_space *vm)
return vm->scratch_order == get_order(I915_GTT_PAGE_SIZE_64K);
}

+static inline u64 i915_vm_min_alignment(struct i915_address_space *vm,
+ enum intel_memory_type type)
+{
+ return vm->min_alignment[type];
+}
+
+static inline u64 i915_vm_obj_min_alignment(struct i915_address_space *vm,
+ struct drm_i915_gem_object *obj)
+{
+ return i915_vm_min_alignment(vm, READ_ONCE(obj->mm.region)->type);
+}
+
static inline bool
i915_vm_has_cache_coloring(struct i915_address_space *vm)
{
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index b959e904c4d3..3b31d2ba6864 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -745,6 +745,14 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
end = min_t(u64, end, (1ULL << 32) - I915_GTT_PAGE_SIZE);
GEM_BUG_ON(!IS_ALIGNED(end, I915_GTT_PAGE_SIZE));

+ alignment = max(alignment, i915_vm_obj_min_alignment(vma->vm, vma->obj));
+ /*
+ * for compact-pt we round up the reservation to prevent
+ * any smaller pages being used within the same PDE
+ */
+ if (NEEDS_COMPACT_PT(vma->vm->i915))
+ size = round_up(size, alignment);
+
/* If binding the object/GGTT view requires more space than the entire
* aperture has, reject it early before evicting everything in a vain
* attempt to find space.
@@ -757,6 +765,7 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
}

color = 0;
+
if (i915_vm_has_cache_coloring(vma->vm))
color = vma->obj->cache_level;

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index fba1c8be1649..b80788a2b7f9 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -238,6 +238,8 @@ static int lowlevel_hole(struct i915_address_space *vm,
u64 hole_start, u64 hole_end,
unsigned long end_time)
{
+ const unsigned int min_alignment =
+ i915_vm_min_alignment(vm, INTEL_MEMORY_SYSTEM);
I915_RND_STATE(seed_prng);
struct i915_vma_resource *mock_vma_res;
unsigned int size;
@@ -251,9 +253,10 @@ static int lowlevel_hole(struct i915_address_space *vm,
I915_RND_SUBSTATE(prng, seed_prng);
struct drm_i915_gem_object *obj;
unsigned int *order, count, n;
- u64 hole_size;
+ u64 hole_size, aligned_size;

- hole_size = (hole_end - hole_start) >> size;
+ aligned_size = max_t(u32, ilog2(min_alignment), size);
+ hole_size = (hole_end - hole_start) >> aligned_size;
if (hole_size > KMALLOC_MAX_SIZE / sizeof(u32))
hole_size = KMALLOC_MAX_SIZE / sizeof(u32);
count = hole_size >> 1;
@@ -274,8 +277,8 @@ static int lowlevel_hole(struct i915_address_space *vm,
}
GEM_BUG_ON(!order);

- GEM_BUG_ON(count * BIT_ULL(size) > vm->total);
- GEM_BUG_ON(hole_start + count * BIT_ULL(size) > hole_end);
+ GEM_BUG_ON(count * BIT_ULL(aligned_size) > vm->total);
+ GEM_BUG_ON(hole_start + count * BIT_ULL(aligned_size) > hole_end);

/* Ignore allocation failures (i.e. don't report them as
* a test failure) as we are purposefully allocating very
@@ -298,10 +301,10 @@ static int lowlevel_hole(struct i915_address_space *vm,
}

for (n = 0; n < count; n++) {
- u64 addr = hole_start + order[n] * BIT_ULL(size);
+ u64 addr = hole_start + order[n] * BIT_ULL(aligned_size);
intel_wakeref_t wakeref;

- GEM_BUG_ON(addr + BIT_ULL(size) > vm->total);
+ GEM_BUG_ON(addr + BIT_ULL(aligned_size) > vm->total);

if (igt_timeout(end_time,
"%s timed out before %d/%d\n",
@@ -344,7 +347,7 @@ static int lowlevel_hole(struct i915_address_space *vm,
}

mock_vma_res->bi.pages = obj->mm.pages;
- mock_vma_res->node_size = BIT_ULL(size);
+ mock_vma_res->node_size = BIT_ULL(aligned_size);
mock_vma_res->start = addr;

with_intel_runtime_pm(vm->gt->uncore->rpm, wakeref)
@@ -355,7 +358,7 @@ static int lowlevel_hole(struct i915_address_space *vm,

i915_random_reorder(order, count, &prng);
for (n = 0; n < count; n++) {
- u64 addr = hole_start + order[n] * BIT_ULL(size);
+ u64 addr = hole_start + order[n] * BIT_ULL(aligned_size);
intel_wakeref_t wakeref;

GEM_BUG_ON(addr + BIT_ULL(size) > vm->total);
@@ -399,8 +402,10 @@ static int fill_hole(struct i915_address_space *vm,
{
const u64 hole_size = hole_end - hole_start;
struct drm_i915_gem_object *obj;
+ const unsigned int min_alignment =
+ i915_vm_min_alignment(vm, INTEL_MEMORY_SYSTEM);
const unsigned long max_pages =
- min_t(u64, ULONG_MAX - 1, hole_size/2 >> PAGE_SHIFT);
+ min_t(u64, ULONG_MAX - 1, (hole_size / 2) >> ilog2(min_alignment));
const unsigned long max_step = max(int_sqrt(max_pages), 2UL);
unsigned long npages, prime, flags;
struct i915_vma *vma;
@@ -441,14 +446,17 @@ static int fill_hole(struct i915_address_space *vm,

offset = p->offset;
list_for_each_entry(obj, &objects, st_link) {
+ u64 aligned_size = round_up(obj->base.size,
+ min_alignment);
+
vma = i915_vma_instance(obj, vm, NULL);
if (IS_ERR(vma))
continue;

if (p->step < 0) {
- if (offset < hole_start + obj->base.size)
+ if (offset < hole_start + aligned_size)
break;
- offset -= obj->base.size;
+ offset -= aligned_size;
}

err = i915_vma_pin(vma, 0, 0, offset | flags);
@@ -470,22 +478,25 @@ static int fill_hole(struct i915_address_space *vm,
i915_vma_unpin(vma);

if (p->step > 0) {
- if (offset + obj->base.size > hole_end)
+ if (offset + aligned_size > hole_end)
break;
- offset += obj->base.size;
+ offset += aligned_size;
}
}

offset = p->offset;
list_for_each_entry(obj, &objects, st_link) {
+ u64 aligned_size = round_up(obj->base.size,
+ min_alignment);
+
vma = i915_vma_instance(obj, vm, NULL);
if (IS_ERR(vma))
continue;

if (p->step < 0) {
- if (offset < hole_start + obj->base.size)
+ if (offset < hole_start + aligned_size)
break;
- offset -= obj->base.size;
+ offset -= aligned_size;
}

if (!drm_mm_node_allocated(&vma->node) ||
@@ -506,22 +517,25 @@ static int fill_hole(struct i915_address_space *vm,
}

if (p->step > 0) {
- if (offset + obj->base.size > hole_end)
+ if (offset + aligned_size > hole_end)
break;
- offset += obj->base.size;
+ offset += aligned_size;
}
}

offset = p->offset;
list_for_each_entry_reverse(obj, &objects, st_link) {
+ u64 aligned_size = round_up(obj->base.size,
+ min_alignment);
+
vma = i915_vma_instance(obj, vm, NULL);
if (IS_ERR(vma))
continue;

if (p->step < 0) {
- if (offset < hole_start + obj->base.size)
+ if (offset < hole_start + aligned_size)
break;
- offset -= obj->base.size;
+ offset -= aligned_size;
}

err = i915_vma_pin(vma, 0, 0, offset | flags);
@@ -543,22 +557,25 @@ static int fill_hole(struct i915_address_space *vm,
i915_vma_unpin(vma);

if (p->step > 0) {
- if (offset + obj->base.size > hole_end)
+ if (offset + aligned_size > hole_end)
break;
- offset += obj->base.size;
+ offset += aligned_size;
}
}

offset = p->offset;
list_for_each_entry_reverse(obj, &objects, st_link) {
+ u64 aligned_size = round_up(obj->base.size,
+ min_alignment);
+
vma = i915_vma_instance(obj, vm, NULL);
if (IS_ERR(vma))
continue;

if (p->step < 0) {
- if (offset < hole_start + obj->base.size)
+ if (offset < hole_start + aligned_size)
break;
- offset -= obj->base.size;
+ offset -= aligned_size;
}

if (!drm_mm_node_allocated(&vma->node) ||
@@ -579,9 +596,9 @@ static int fill_hole(struct i915_address_space *vm,
}

if (p->step > 0) {
- if (offset + obj->base.size > hole_end)
+ if (offset + aligned_size > hole_end)
break;
- offset += obj->base.size;
+ offset += aligned_size;
}
}
}
@@ -611,6 +628,7 @@ static int walk_hole(struct i915_address_space *vm,
const u64 hole_size = hole_end - hole_start;
const unsigned long max_pages =
min_t(u64, ULONG_MAX - 1, hole_size >> PAGE_SHIFT);
+ unsigned long min_alignment;
unsigned long flags;
u64 size;

@@ -620,6 +638,8 @@ static int walk_hole(struct i915_address_space *vm,
if (i915_is_ggtt(vm))
flags |= PIN_GLOBAL;

+ min_alignment = i915_vm_min_alignment(vm, INTEL_MEMORY_SYSTEM);
+
for_each_prime_number_from(size, 1, max_pages) {
struct drm_i915_gem_object *obj;
struct i915_vma *vma;
@@ -638,7 +658,7 @@ static int walk_hole(struct i915_address_space *vm,

for (addr = hole_start;
addr + obj->base.size < hole_end;
- addr += obj->base.size) {
+ addr += round_up(obj->base.size, min_alignment)) {
err = i915_vma_pin(vma, 0, 0, addr | flags);
if (err) {
pr_err("%s bind failed at %llx + %llx [hole %llx- %llx] with err=%d\n",
@@ -690,6 +710,7 @@ static int pot_hole(struct i915_address_space *vm,
{
struct drm_i915_gem_object *obj;
struct i915_vma *vma;
+ unsigned int min_alignment;
unsigned long flags;
unsigned int pot;
int err = 0;
@@ -698,6 +719,8 @@ static int pot_hole(struct i915_address_space *vm,
if (i915_is_ggtt(vm))
flags |= PIN_GLOBAL;

+ min_alignment = i915_vm_min_alignment(vm, INTEL_MEMORY_SYSTEM);
+
obj = i915_gem_object_create_internal(vm->i915, 2 * I915_GTT_PAGE_SIZE);
if (IS_ERR(obj))
return PTR_ERR(obj);
@@ -710,13 +733,13 @@ static int pot_hole(struct i915_address_space *vm,

/* Insert a pair of pages across every pot boundary within the hole */
for (pot = fls64(hole_end - 1) - 1;
- pot > ilog2(2 * I915_GTT_PAGE_SIZE);
+ pot > ilog2(2 * min_alignment);
pot--) {
u64 step = BIT_ULL(pot);
u64 addr;

- for (addr = round_up(hole_start + I915_GTT_PAGE_SIZE, step) - I915_GTT_PAGE_SIZE;
- addr <= round_down(hole_end - 2*I915_GTT_PAGE_SIZE, step) - I915_GTT_PAGE_SIZE;
+ for (addr = round_up(hole_start + min_alignment, step) - min_alignment;
+ addr <= round_down(hole_end - (2 * min_alignment), step) - min_alignment;
addr += step) {
err = i915_vma_pin(vma, 0, 0, addr | flags);
if (err) {
@@ -761,6 +784,7 @@ static int drunk_hole(struct i915_address_space *vm,
unsigned long end_time)
{
I915_RND_STATE(prng);
+ unsigned int min_alignment;
unsigned int size;
unsigned long flags;

@@ -768,15 +792,18 @@ static int drunk_hole(struct i915_address_space *vm,
if (i915_is_ggtt(vm))
flags |= PIN_GLOBAL;

+ min_alignment = i915_vm_min_alignment(vm, INTEL_MEMORY_SYSTEM);
+
/* Keep creating larger objects until one cannot fit into the hole */
for (size = 12; (hole_end - hole_start) >> size; size++) {
struct drm_i915_gem_object *obj;
unsigned int *order, count, n;
struct i915_vma *vma;
- u64 hole_size;
+ u64 hole_size, aligned_size;
int err = -ENODEV;

- hole_size = (hole_end - hole_start) >> size;
+ aligned_size = max_t(u32, ilog2(min_alignment), size);
+ hole_size = (hole_end - hole_start) >> aligned_size;
if (hole_size > KMALLOC_MAX_SIZE / sizeof(u32))
hole_size = KMALLOC_MAX_SIZE / sizeof(u32);
count = hole_size >> 1;
@@ -816,7 +843,7 @@ static int drunk_hole(struct i915_address_space *vm,
GEM_BUG_ON(vma->size != BIT_ULL(size));

for (n = 0; n < count; n++) {
- u64 addr = hole_start + order[n] * BIT_ULL(size);
+ u64 addr = hole_start + order[n] * BIT_ULL(aligned_size);

err = i915_vma_pin(vma, 0, 0, addr | flags);
if (err) {
@@ -868,11 +895,14 @@ static int __shrink_hole(struct i915_address_space *vm,
{
struct drm_i915_gem_object *obj;
unsigned long flags = PIN_OFFSET_FIXED | PIN_USER;
+ unsigned int min_alignment;
unsigned int order = 12;
LIST_HEAD(objects);
int err = 0;
u64 addr;

+ min_alignment = i915_vm_min_alignment(vm, INTEL_MEMORY_SYSTEM);
+
/* Keep creating larger objects until one cannot fit into the hole */
for (addr = hole_start; addr < hole_end; ) {
struct i915_vma *vma;
@@ -913,7 +943,7 @@ static int __shrink_hole(struct i915_address_space *vm,
}

i915_vma_unpin(vma);
- addr += size;
+ addr += round_up(size, min_alignment);

/*
* Since we are injecting allocation faults at random intervals,
--
2.25.1