Re: [Intel-gfx] [PATCH 14/20] drm/i915/selftests: exercise mmap migration

Thomas Hellström
2022-02-03T09:01:10Z

On 1/26/22 16:21, Matthew Auld wrote:
> Exercise each of the migration scenarios, verifying that the final
> placement and buffer contents match our expectations.
>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> ---
> .../drm/i915/gem/selftests/i915_gem_mman.c | 306 ++++++++++++++++++
> 1 file changed, 306 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 ba29767348be..d2c1071df98a 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
> @@ -10,6 +10,7 @@
> #include "gt/intel_gpu_commands.h"
> #include "gt/intel_gt.h"
> #include "gt/intel_gt_pm.h"
> +#include "gt/intel_migrate.h"
> #include "gem/i915_gem_region.h"
> #include "huge_gem_object.h"
> #include "i915_selftest.h"
> @@ -999,6 +1000,310 @@ 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_TOPDOWN;
> + 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_gem_ww_ctx ww;
> + 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_TOPDOWN;
> +
> + 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;
> + }
> +
> + for_i915_gem_ww(&ww, err, true) {

Do we need a full ww transaction here? Sufficient to only lock the
object with NULL?

> + err = i915_gem_object_lock(obj, &ww);
> + if (err)
> + continue;
> +
> + err = i915_gem_object_pin_pages(obj);
> + if (err)
> + continue;
> +
> + 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);
> + }
> + if (err)
> + continue;
Not needed?
> + }
> + 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 };
> + int err;
> +
> + if (mr->private)
> + continue;
> +
> + if (!mr->io_size || mr->io_size == mr->total)
> + continue;
> +
> + /*
> + * Allocate in the mappable portion, should be no suprises here.
> + */
> + err = __igt_mmap_migrate(mixed, ARRAY_SIZE(mixed), mr, 0);
> + if (err)
> + return err;
> +
> + /*
> + * 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)
> + return err;
> +
> + /*
> + * 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)
> + return err;
> +
> + /*
> + * 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);
> + if (err)
> + return err;
> + }
> +
> + return 0;
> +}
> +
> static const char *repr_mmap_type(enum i915_mmap_type type)
> {
> switch (type) {
> @@ -1424,6 +1729,7 @@ 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),