* [PATCH v6 1/5] drm/i915: add needs_compact_pt flag
2022-01-31 18:52 [PATCH v6 0/5] discrete card 64K page support Robert Beckett
@ 2022-01-31 18:52 ` Robert Beckett
2022-01-31 18:52 ` [PATCH v6 2/5] drm/i915: enforce min GTT alignment for discrete cards Robert Beckett
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Robert Beckett @ 2022-01-31 18:52 UTC (permalink / raw)
To: Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin,
David Airlie, Daniel Vetter
Cc: Robert Beckett, Thomas Hellström, intel-gfx, linux-kernel,
dri-devel, Matthew Auld
From: Ramalingam C <ramalingam.c@intel.com>
Add a new platform flag, needs_compact_pt, to mark the requirement of
compact pt layout support for the ppGTT when using 64K GTT pages.
With this flag has_64k_pages will only indicate requirement of 64K
GTT page sizes or larger for device local memory access.
v6:
* minor doc formatting
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 11 ++++++++---
drivers/gpu/drm/i915/i915_pci.c | 2 ++
drivers/gpu/drm/i915/intel_device_info.h | 1 +
3 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 00e7594b59c9..4afdfa5fd3b3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1512,12 +1512,17 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
/*
* Set this flag, when platform requires 64K GTT page sizes or larger for
- * device local memory access. Also this flag implies that we require or
- * at least support the compact PT layout for the ppGTT when using the 64K
- * GTT pages.
+ * device local memory access.
*/
#define HAS_64K_PAGES(dev_priv) (INTEL_INFO(dev_priv)->has_64k_pages)
+/*
+ * Set this flag when platform doesn't allow both 64k pages and 4k pages in
+ * the same PT. this flag means we need to support compact PT layout for the
+ * ppGTT when using the 64K GTT pages.
+ */
+#define NEEDS_COMPACT_PT(dev_priv) (INTEL_INFO(dev_priv)->needs_compact_pt)
+
#define HAS_IPC(dev_priv) (INTEL_INFO(dev_priv)->display.has_ipc)
#define HAS_REGION(i915, i) (INTEL_INFO(i915)->memory_regions & (i))
diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index 2df2db0a5d70..ce6ae6a3cbdf 100644
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -1028,6 +1028,7 @@ static const struct intel_device_info xehpsdv_info = {
PLATFORM(INTEL_XEHPSDV),
.display = { },
.has_64k_pages = 1,
+ .needs_compact_pt = 1,
.platform_engine_mask =
BIT(RCS0) | BIT(BCS0) |
BIT(VECS0) | BIT(VECS1) | BIT(VECS2) | BIT(VECS3) |
@@ -1046,6 +1047,7 @@ static const struct intel_device_info dg2_info = {
PLATFORM(INTEL_DG2),
.has_guc_deprivilege = 1,
.has_64k_pages = 1,
+ .needs_compact_pt = 1,
.platform_engine_mask =
BIT(RCS0) | BIT(BCS0) |
BIT(VECS0) | BIT(VECS1) |
diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
index abf1e103c558..d8da40d01dca 100644
--- a/drivers/gpu/drm/i915/intel_device_info.h
+++ b/drivers/gpu/drm/i915/intel_device_info.h
@@ -130,6 +130,7 @@ enum intel_ppgtt_type {
/* Keep has_* in alphabetical order */ \
func(has_64bit_reloc); \
func(has_64k_pages); \
+ func(needs_compact_pt); \
func(gpu_reset_clobbers_display); \
func(has_reset_engine); \
func(has_global_mocs); \
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v6 2/5] drm/i915: enforce min GTT alignment for discrete cards
2022-01-31 18:52 [PATCH v6 0/5] discrete card 64K page support Robert Beckett
2022-01-31 18:52 ` [PATCH v6 1/5] drm/i915: add needs_compact_pt flag Robert Beckett
@ 2022-01-31 18:52 ` Robert Beckett
2022-01-31 18:52 ` [PATCH v6 3/5] drm/i915: support 64K GTT pages " Robert Beckett
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Robert Beckett @ 2022-01-31 18:52 UTC (permalink / raw)
To: Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin,
David Airlie, Daniel Vetter
Cc: Robert Beckett, Thomas Hellström, intel-gfx, linux-kernel,
dri-devel, Matthew Auld
From: Matthew Auld <matthew.auld@intel.com>
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
v5:
* fix i915_vm_obj_min_alignment for internal objects which
have no memory region
v6:
* tiled_blits_create correctly pick largest required alignment
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
.../i915/gem/selftests/i915_gem_client_blt.c | 21 ++--
drivers/gpu/drm/i915/gt/intel_gtt.c | 12 +++
drivers/gpu/drm/i915/gt/intel_gtt.h | 18 ++++
drivers/gpu/drm/i915/i915_vma.c | 9 ++
drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 96 ++++++++++++-------
5 files changed, 115 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..3675d12a7d9a 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 +411,19 @@ 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_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 +434,7 @@ 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 +461,7 @@ 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 +492,7 @@ 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 +505,7 @@ 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..ba9f040f8606 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 +387,21 @@ 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)
+{
+ struct intel_memory_region *mr = READ_ONCE(obj->mm.region);
+ enum intel_memory_type type = mr ? mr->type : INTEL_MEMORY_SYSTEM;
+
+ return i915_vm_min_alignment(vm, 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 845cd88f8313..3558b16a929c 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -757,6 +757,14 @@ 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.
@@ -769,6 +777,7 @@ 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
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v6 3/5] drm/i915: support 64K GTT pages for discrete cards
2022-01-31 18:52 [PATCH v6 0/5] discrete card 64K page support Robert Beckett
2022-01-31 18:52 ` [PATCH v6 1/5] drm/i915: add needs_compact_pt flag Robert Beckett
2022-01-31 18:52 ` [PATCH v6 2/5] drm/i915: enforce min GTT alignment for discrete cards Robert Beckett
@ 2022-01-31 18:52 ` Robert Beckett
2022-01-31 18:52 ` [PATCH v6 4/5] drm/i915: add gtt misalignment test Robert Beckett
2022-01-31 18:52 ` [PATCH v6 5/5] drm/i915/uapi: document behaviour for DG2 64K support Robert Beckett
4 siblings, 0 replies; 6+ messages in thread
From: Robert Beckett @ 2022-01-31 18:52 UTC (permalink / raw)
To: Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin,
David Airlie, Daniel Vetter
Cc: Robert Beckett, Thomas Hellström, kernel test robot,
intel-gfx, linux-kernel, dri-devel, Stuart Summers, Matthew Auld
From: Matthew Auld <matthew.auld@intel.com>
discrete cards optimise 64K GTT pages for local-memory, since everything
should be allocated at 64K granularity. We say goodbye to sparse
entries, and instead get a compact 256B page-table for 64K pages,
which should be more cache friendly. 4K pages for local-memory
are no longer supported by the HW.
v4: don't return uninitialized err in igt_ppgtt_compact
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
.../gpu/drm/i915/gem/selftests/huge_pages.c | 60 ++++++++++
drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 108 +++++++++++++++++-
drivers/gpu/drm/i915/gt/intel_gtt.h | 3 +
drivers/gpu/drm/i915/gt/intel_ppgtt.c | 1 +
4 files changed, 169 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
index f36191ebf964..a7d9bdb85d70 100644
--- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
@@ -1478,6 +1478,65 @@ static int igt_ppgtt_sanity_check(void *arg)
return err;
}
+static int igt_ppgtt_compact(void *arg)
+{
+ struct drm_i915_private *i915 = arg;
+ struct drm_i915_gem_object *obj;
+ int err;
+
+ /*
+ * Simple test to catch issues with compact 64K pages -- since the pt is
+ * compacted to 256B that gives us 32 entries per pt, however since the
+ * backing page for the pt is 4K, any extra entries we might incorrectly
+ * write out should be ignored by the HW. If ever hit such a case this
+ * test should catch it since some of our writes would land in scratch.
+ */
+
+ if (!HAS_64K_PAGES(i915)) {
+ pr_info("device lacks compact 64K page support, skipping\n");
+ return 0;
+ }
+
+ if (!HAS_LMEM(i915)) {
+ pr_info("device lacks LMEM support, skipping\n");
+ return 0;
+ }
+
+ /* We want the range to cover multiple page-table boundaries. */
+ obj = i915_gem_object_create_lmem(i915, SZ_4M, 0);
+ if (IS_ERR(obj))
+ return PTR_ERR(obj);
+
+ err = i915_gem_object_pin_pages_unlocked(obj);
+ if (err)
+ goto out_put;
+
+ if (obj->mm.page_sizes.phys < I915_GTT_PAGE_SIZE_64K) {
+ pr_info("LMEM compact unable to allocate huge-page(s)\n");
+ goto out_unpin;
+ }
+
+ /*
+ * Disable 2M GTT pages by forcing the page-size to 64K for the GTT
+ * insertion.
+ */
+ obj->mm.page_sizes.sg = I915_GTT_PAGE_SIZE_64K;
+
+ err = igt_write_huge(i915, obj);
+ if (err)
+ pr_err("LMEM compact write-huge failed\n");
+
+out_unpin:
+ i915_gem_object_unpin_pages(obj);
+out_put:
+ i915_gem_object_put(obj);
+
+ if (err == -ENOMEM)
+ err = 0;
+
+ return err;
+}
+
static int igt_tmpfs_fallback(void *arg)
{
struct drm_i915_private *i915 = arg;
@@ -1735,6 +1794,7 @@ int i915_gem_huge_page_live_selftests(struct drm_i915_private *i915)
SUBTEST(igt_tmpfs_fallback),
SUBTEST(igt_ppgtt_smoke_huge),
SUBTEST(igt_ppgtt_sanity_check),
+ SUBTEST(igt_ppgtt_compact),
};
if (!HAS_PPGTT(i915)) {
diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
index c43e724afa9f..62471730266c 100644
--- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
@@ -233,6 +233,8 @@ static u64 __gen8_ppgtt_clear(struct i915_address_space * const vm,
start, end, lvl);
} else {
unsigned int count;
+ unsigned int pte = gen8_pd_index(start, 0);
+ unsigned int num_ptes;
u64 *vaddr;
count = gen8_pt_count(start, end);
@@ -242,10 +244,18 @@ static u64 __gen8_ppgtt_clear(struct i915_address_space * const vm,
atomic_read(&pt->used));
GEM_BUG_ON(!count || count >= atomic_read(&pt->used));
+ num_ptes = count;
+ if (pt->is_compact) {
+ GEM_BUG_ON(num_ptes % 16);
+ GEM_BUG_ON(pte % 16);
+ num_ptes /= 16;
+ pte /= 16;
+ }
+
vaddr = px_vaddr(pt);
- memset64(vaddr + gen8_pd_index(start, 0),
+ memset64(vaddr + pte,
vm->scratch[0]->encode,
- count);
+ num_ptes);
atomic_sub(count, &pt->used);
start += count;
@@ -453,6 +463,95 @@ gen8_ppgtt_insert_pte(struct i915_ppgtt *ppgtt,
return idx;
}
+static void
+xehpsdv_ppgtt_insert_huge(struct i915_address_space *vm,
+ struct i915_vma_resource *vma_res,
+ struct sgt_dma *iter,
+ enum i915_cache_level cache_level,
+ u32 flags)
+{
+ const gen8_pte_t pte_encode = vm->pte_encode(0, cache_level, flags);
+ unsigned int rem = sg_dma_len(iter->sg);
+ u64 start = vma_res->start;
+
+ GEM_BUG_ON(!i915_vm_is_4lvl(vm));
+
+ do {
+ struct i915_page_directory * const pdp =
+ gen8_pdp_for_page_address(vm, start);
+ struct i915_page_directory * const pd =
+ i915_pd_entry(pdp, __gen8_pte_index(start, 2));
+ struct i915_page_table *pt =
+ i915_pt_entry(pd, __gen8_pte_index(start, 1));
+ gen8_pte_t encode = pte_encode;
+ unsigned int page_size;
+ gen8_pte_t *vaddr;
+ u16 index, max;
+
+ max = I915_PDES;
+
+ if (vma_res->bi.page_sizes.sg & I915_GTT_PAGE_SIZE_2M &&
+ IS_ALIGNED(iter->dma, I915_GTT_PAGE_SIZE_2M) &&
+ rem >= I915_GTT_PAGE_SIZE_2M &&
+ !__gen8_pte_index(start, 0)) {
+ index = __gen8_pte_index(start, 1);
+ encode |= GEN8_PDE_PS_2M;
+ page_size = I915_GTT_PAGE_SIZE_2M;
+
+ vaddr = px_vaddr(pd);
+ } else {
+ if (encode & GEN12_PPGTT_PTE_LM) {
+ GEM_BUG_ON(__gen8_pte_index(start, 0) % 16);
+ GEM_BUG_ON(rem < I915_GTT_PAGE_SIZE_64K);
+ GEM_BUG_ON(!IS_ALIGNED(iter->dma,
+ I915_GTT_PAGE_SIZE_64K));
+
+ index = __gen8_pte_index(start, 0) / 16;
+ page_size = I915_GTT_PAGE_SIZE_64K;
+
+ max /= 16;
+
+ vaddr = px_vaddr(pd);
+ vaddr[__gen8_pte_index(start, 1)] |= GEN12_PDE_64K;
+
+ pt->is_compact = true;
+ } else {
+ GEM_BUG_ON(pt->is_compact);
+ index = __gen8_pte_index(start, 0);
+ page_size = I915_GTT_PAGE_SIZE;
+ }
+
+ vaddr = px_vaddr(pt);
+ }
+
+ do {
+ GEM_BUG_ON(rem < page_size);
+ vaddr[index++] = encode | iter->dma;
+
+ start += page_size;
+ iter->dma += page_size;
+ rem -= page_size;
+ if (iter->dma >= iter->max) {
+ iter->sg = __sg_next(iter->sg);
+ if (!iter->sg)
+ break;
+
+ rem = sg_dma_len(iter->sg);
+ if (!rem)
+ break;
+
+ iter->dma = sg_dma_address(iter->sg);
+ iter->max = iter->dma + rem;
+
+ if (unlikely(!IS_ALIGNED(iter->dma, page_size)))
+ break;
+ }
+ } while (rem >= page_size && index < max);
+
+ vma_res->page_sizes_gtt |= page_size;
+ } while (iter->sg && sg_dma_len(iter->sg));
+}
+
static void gen8_ppgtt_insert_huge(struct i915_address_space *vm,
struct i915_vma_resource *vma_res,
struct sgt_dma *iter,
@@ -586,7 +685,10 @@ static void gen8_ppgtt_insert(struct i915_address_space *vm,
struct sgt_dma iter = sgt_dma(vma_res);
if (vma_res->bi.page_sizes.sg > I915_GTT_PAGE_SIZE) {
- gen8_ppgtt_insert_huge(vm, vma_res, &iter, cache_level, flags);
+ if (HAS_64K_PAGES(vm->i915))
+ xehpsdv_ppgtt_insert_huge(vm, vma_res, &iter, cache_level, flags);
+ else
+ gen8_ppgtt_insert_huge(vm, vma_res, &iter, cache_level, flags);
} else {
u64 idx = vma_res->start >> GEN8_PTE_SHIFT;
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index ba9f040f8606..e6ce0be6d484 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -92,6 +92,8 @@ typedef u64 gen8_pte_t;
#define GEN12_GGTT_PTE_LM BIT_ULL(1)
+#define GEN12_PDE_64K BIT(6)
+
/*
* Cacheability Control is a 4-bit value. The low three bits are stored in bits
* 3:1 of the PTE, while the fourth bit is stored in bit 11 of the PTE.
@@ -160,6 +162,7 @@ struct i915_page_table {
atomic_t used;
struct i915_page_table *stash;
};
+ bool is_compact;
};
struct i915_page_directory {
diff --git a/drivers/gpu/drm/i915/gt/intel_ppgtt.c b/drivers/gpu/drm/i915/gt/intel_ppgtt.c
index 48e6e2f87700..043652dc6892 100644
--- a/drivers/gpu/drm/i915/gt/intel_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ppgtt.c
@@ -26,6 +26,7 @@ struct i915_page_table *alloc_pt(struct i915_address_space *vm)
return ERR_PTR(-ENOMEM);
}
+ pt->is_compact = false;
atomic_set(&pt->used, 0);
return pt;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v6 4/5] drm/i915: add gtt misalignment test
2022-01-31 18:52 [PATCH v6 0/5] discrete card 64K page support Robert Beckett
` (2 preceding siblings ...)
2022-01-31 18:52 ` [PATCH v6 3/5] drm/i915: support 64K GTT pages " Robert Beckett
@ 2022-01-31 18:52 ` Robert Beckett
2022-01-31 18:52 ` [PATCH v6 5/5] drm/i915/uapi: document behaviour for DG2 64K support Robert Beckett
4 siblings, 0 replies; 6+ messages in thread
From: Robert Beckett @ 2022-01-31 18:52 UTC (permalink / raw)
To: Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin,
David Airlie, Daniel Vetter
Cc: Robert Beckett, Thomas Hellström, kernel test robot,
intel-gfx, linux-kernel, dri-devel
add test to check handling of misaligned offsets and sizes
v4:
* remove spurious blank lines
* explicitly cast intel_region_id to intel_memory_type in misaligned_pin
Reported-by: kernel test robot <lkp@intel.com>
v6:
* use NEEDS_COMPACT_PT instead of hard coding for DG2
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 128 ++++++++++++++++++
1 file changed, 128 insertions(+)
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index b80788a2b7f9..c23b1e5cc436 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -22,10 +22,12 @@
*
*/
+#include "gt/intel_gtt.h"
#include <linux/list_sort.h>
#include <linux/prime_numbers.h>
#include "gem/i915_gem_context.h"
+#include "gem/i915_gem_region.h"
#include "gem/selftests/mock_context.h"
#include "gt/intel_context.h"
#include "gt/intel_gpu_commands.h"
@@ -1067,6 +1069,120 @@ static int shrink_boom(struct i915_address_space *vm,
return err;
}
+static int misaligned_case(struct i915_address_space *vm, struct intel_memory_region *mr,
+ u64 addr, u64 size, unsigned long flags)
+{
+ struct drm_i915_gem_object *obj;
+ struct i915_vma *vma;
+ int err = 0;
+ u64 expected_vma_size, expected_node_size;
+
+ obj = i915_gem_object_create_region(mr, size, 0, 0);
+ if (IS_ERR(obj))
+ return PTR_ERR(obj);
+
+ vma = i915_vma_instance(obj, vm, NULL);
+ if (IS_ERR(vma)) {
+ err = PTR_ERR(vma);
+ goto err_put;
+ }
+
+ err = i915_vma_pin(vma, 0, 0, addr | flags);
+ if (err)
+ goto err_put;
+ i915_vma_unpin(vma);
+
+ if (!drm_mm_node_allocated(&vma->node)) {
+ err = -EINVAL;
+ goto err_put;
+ }
+
+ if (i915_vma_misplaced(vma, 0, 0, addr | flags)) {
+ err = -EINVAL;
+ goto err_put;
+ }
+
+ expected_vma_size = round_up(size, 1 << (ffs(vma->resource->page_sizes_gtt) - 1));
+ expected_node_size = expected_vma_size;
+
+ if (NEEDS_COMPACT_PT(vm->i915) && i915_gem_object_is_lmem(obj)) {
+ /* compact-pt should expand lmem node to 2MB */
+ expected_vma_size = round_up(size, I915_GTT_PAGE_SIZE_64K);
+ expected_node_size = round_up(size, I915_GTT_PAGE_SIZE_2M);
+ }
+
+ if (vma->size != expected_vma_size || vma->node.size != expected_node_size) {
+ err = i915_vma_unbind(vma);
+ err = -EBADSLT;
+ goto err_put;
+ }
+
+ err = i915_vma_unbind(vma);
+ if (err)
+ goto err_put;
+
+ GEM_BUG_ON(drm_mm_node_allocated(&vma->node));
+
+err_put:
+ i915_gem_object_put(obj);
+ cleanup_freed_objects(vm->i915);
+ return err;
+}
+
+static int misaligned_pin(struct i915_address_space *vm,
+ u64 hole_start, u64 hole_end,
+ unsigned long end_time)
+{
+ struct intel_memory_region *mr;
+ enum intel_region_id id;
+ unsigned long flags = PIN_OFFSET_FIXED | PIN_USER;
+ int err = 0;
+ u64 hole_size = hole_end - hole_start;
+
+ if (i915_is_ggtt(vm))
+ flags |= PIN_GLOBAL;
+
+ for_each_memory_region(mr, vm->i915, id) {
+ u64 min_alignment = i915_vm_min_alignment(vm, (enum intel_memory_type)id);
+ u64 size = min_alignment;
+ u64 addr = round_up(hole_start + (hole_size / 2), min_alignment);
+
+ /* we can't test < 4k alignment due to flags being encoded in lower bits */
+ if (min_alignment != I915_GTT_PAGE_SIZE_4K) {
+ err = misaligned_case(vm, mr, addr + (min_alignment / 2), size, flags);
+ /* misaligned should error with -EINVAL*/
+ if (!err)
+ err = -EBADSLT;
+ if (err != -EINVAL)
+ return err;
+ }
+
+ /* test for vma->size expansion to min page size */
+ err = misaligned_case(vm, mr, addr, PAGE_SIZE, flags);
+ if (min_alignment > hole_size) {
+ if (!err)
+ err = -EBADSLT;
+ else if (err == -ENOSPC)
+ err = 0;
+ }
+ if (err)
+ return err;
+
+ /* test for intermediate size not expanding vma->size for large alignments */
+ err = misaligned_case(vm, mr, addr, size / 2, flags);
+ if (min_alignment > hole_size) {
+ if (!err)
+ err = -EBADSLT;
+ else if (err == -ENOSPC)
+ err = 0;
+ }
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
static int exercise_ppgtt(struct drm_i915_private *dev_priv,
int (*func)(struct i915_address_space *vm,
u64 hole_start, u64 hole_end,
@@ -1136,6 +1252,11 @@ static int igt_ppgtt_shrink_boom(void *arg)
return exercise_ppgtt(arg, shrink_boom);
}
+static int igt_ppgtt_misaligned_pin(void *arg)
+{
+ return exercise_ppgtt(arg, misaligned_pin);
+}
+
static int sort_holes(void *priv, const struct list_head *A,
const struct list_head *B)
{
@@ -1208,6 +1329,11 @@ static int igt_ggtt_lowlevel(void *arg)
return exercise_ggtt(arg, lowlevel_hole);
}
+static int igt_ggtt_misaligned_pin(void *arg)
+{
+ return exercise_ggtt(arg, misaligned_pin);
+}
+
static int igt_ggtt_page(void *arg)
{
const unsigned int count = PAGE_SIZE/sizeof(u32);
@@ -2180,12 +2306,14 @@ int i915_gem_gtt_live_selftests(struct drm_i915_private *i915)
SUBTEST(igt_ppgtt_fill),
SUBTEST(igt_ppgtt_shrink),
SUBTEST(igt_ppgtt_shrink_boom),
+ SUBTEST(igt_ppgtt_misaligned_pin),
SUBTEST(igt_ggtt_lowlevel),
SUBTEST(igt_ggtt_drunk),
SUBTEST(igt_ggtt_walk),
SUBTEST(igt_ggtt_pot),
SUBTEST(igt_ggtt_fill),
SUBTEST(igt_ggtt_page),
+ SUBTEST(igt_ggtt_misaligned_pin),
SUBTEST(igt_cs_tlb),
};
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v6 5/5] drm/i915/uapi: document behaviour for DG2 64K support
2022-01-31 18:52 [PATCH v6 0/5] discrete card 64K page support Robert Beckett
` (3 preceding siblings ...)
2022-01-31 18:52 ` [PATCH v6 4/5] drm/i915: add gtt misalignment test Robert Beckett
@ 2022-01-31 18:52 ` Robert Beckett
4 siblings, 0 replies; 6+ messages in thread
From: Robert Beckett @ 2022-01-31 18:52 UTC (permalink / raw)
To: Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin,
David Airlie, Daniel Vetter
Cc: Robert Beckett, Thomas Hellström, dri-devel, Jordan Justen,
intel-gfx, Kenneth Graunke, Tony Ye, Slawomir Milczarek,
Matthew Auld, mesa-dev, linux-kernel
From: Matthew Auld <matthew.auld@intel.com>
On discrete platforms like DG2, we need to support a minimum page size
of 64K when dealing with device local-memory. This is quite tricky for
various reasons, so try to document the new implicit uapi for this.
v3: fix typos and less emphasis
v2: Fixed suggestions on formatting [Daniel]
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
cc: Simon Ser <contact@emersion.fr>
cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Cc: mesa-dev@lists.freedesktop.org
Cc: Tony Ye <tony.ye@intel.com>
Cc: Slawomir Milczarek <slawomir.milczarek@intel.com>
---
include/uapi/drm/i915_drm.h | 44 ++++++++++++++++++++++++++++++++-----
1 file changed, 39 insertions(+), 5 deletions(-)
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 5e678917da70..77e5e74c32c1 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1118,10 +1118,16 @@ struct drm_i915_gem_exec_object2 {
/**
* When the EXEC_OBJECT_PINNED flag is specified this is populated by
* the user with the GTT offset at which this object will be pinned.
+ *
* When the I915_EXEC_NO_RELOC flag is specified this must contain the
* presumed_offset of the object.
+ *
* During execbuffer2 the kernel populates it with the value of the
* current GTT offset of the object, for future presumed_offset writes.
+ *
+ * See struct drm_i915_gem_create_ext for the rules when dealing with
+ * alignment restrictions with I915_MEMORY_CLASS_DEVICE, on devices with
+ * minimum page sizes, like DG2.
*/
__u64 offset;
@@ -3145,11 +3151,39 @@ struct drm_i915_gem_create_ext {
*
* The (page-aligned) allocated size for the object will be returned.
*
- * Note that for some devices we have might have further minimum
- * page-size restrictions(larger than 4K), like for device local-memory.
- * However in general the final size here should always reflect any
- * rounding up, if for example using the I915_GEM_CREATE_EXT_MEMORY_REGIONS
- * extension to place the object in device local-memory.
+ *
+ * DG2 64K min page size implications:
+ *
+ * On discrete platforms, starting from DG2, we have to contend with GTT
+ * page size restrictions when dealing with I915_MEMORY_CLASS_DEVICE
+ * objects. Specifically the hardware only supports 64K or larger GTT
+ * page sizes for such memory. The kernel will already ensure that all
+ * I915_MEMORY_CLASS_DEVICE memory is allocated using 64K or larger page
+ * sizes underneath.
+ *
+ * Note that the returned size here will always reflect any required
+ * rounding up done by the kernel, i.e 4K will now become 64K on devices
+ * such as DG2.
+ *
+ * Special DG2 GTT address alignment requirement:
+ *
+ * The GTT alignment will also need to be at least 2M for such objects.
+ *
+ * Note that due to how the hardware implements 64K GTT page support, we
+ * have some further complications:
+ *
+ * 1) The entire PDE (which covers a 2MB virtual address range), must
+ * contain only 64K PTEs, i.e mixing 4K and 64K PTEs in the same
+ * PDE is forbidden by the hardware.
+ *
+ * 2) We still need to support 4K PTEs for I915_MEMORY_CLASS_SYSTEM
+ * objects.
+ *
+ * To keep things simple for userland, we mandate that any GTT mappings
+ * must be aligned to and rounded up to 2MB. As this only wastes virtual
+ * address space and avoids userland having to copy any needlessly
+ * complicated PDE sharing scheme (coloring) and only affects DG2, this
+ * is deemed to be a good compromise.
*/
__u64 size;
/**
--
2.25.1
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