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1// SPDX-License-Identifier: MIT2/*3 * Copyright © 2010 Daniel Vetter4 * Copyright © 2020 Intel Corporation5 */6 7#include <linux/slab.h> /* fault-inject.h is not standalone! */8 9#include <linux/fault-inject.h>10#include <linux/log2.h>11#include <linux/random.h>12#include <linux/seq_file.h>13#include <linux/stop_machine.h>14 15#include <asm/set_memory.h>16#include <asm/smp.h>17 18#include "gt/intel_gt.h"19#include "gt/intel_gt_requests.h"20 21#include "i915_drv.h"22#include "i915_gem_evict.h"23#include "i915_scatterlist.h"24#include "i915_trace.h"25#include "i915_vgpu.h"26 27int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj,28 struct sg_table *pages)29{30 do {31 if (dma_map_sg_attrs(obj->base.dev->dev,32 pages->sgl, pages->nents,33 DMA_BIDIRECTIONAL,34 DMA_ATTR_SKIP_CPU_SYNC |35 DMA_ATTR_NO_KERNEL_MAPPING |36 DMA_ATTR_NO_WARN))37 return 0;38 39 /*40 * If the DMA remap fails, one cause can be that we have41 * too many objects pinned in a small remapping table,42 * such as swiotlb. Incrementally purge all other objects and43 * try again - if there are no more pages to remove from44 * the DMA remapper, i915_gem_shrink will return 0.45 */46 GEM_BUG_ON(obj->mm.pages == pages);47 } while (i915_gem_shrink(NULL, to_i915(obj->base.dev),48 obj->base.size >> PAGE_SHIFT, NULL,49 I915_SHRINK_BOUND |50 I915_SHRINK_UNBOUND));51 52 return -ENOSPC;53}54 55void i915_gem_gtt_finish_pages(struct drm_i915_gem_object *obj,56 struct sg_table *pages)57{58 struct drm_i915_private *i915 = to_i915(obj->base.dev);59 struct i915_ggtt *ggtt = to_gt(i915)->ggtt;60 61 /* XXX This does not prevent more requests being submitted! */62 if (unlikely(ggtt->do_idle_maps))63 /* Wait a bit, in the hope it avoids the hang */64 usleep_range(100, 250);65 66 dma_unmap_sg(i915->drm.dev, pages->sgl, pages->nents,67 DMA_BIDIRECTIONAL);68}69 70/**71 * i915_gem_gtt_reserve - reserve a node in an address_space (GTT)72 * @vm: the &struct i915_address_space73 * @ww: An optional struct i915_gem_ww_ctx.74 * @node: the &struct drm_mm_node (typically i915_vma.mode)75 * @size: how much space to allocate inside the GTT,76 * must be #I915_GTT_PAGE_SIZE aligned77 * @offset: where to insert inside the GTT,78 * must be #I915_GTT_MIN_ALIGNMENT aligned, and the node79 * (@offset + @size) must fit within the address space80 * @color: color to apply to node, if this node is not from a VMA,81 * color must be #I915_COLOR_UNEVICTABLE82 * @flags: control search and eviction behaviour83 *84 * i915_gem_gtt_reserve() tries to insert the @node at the exact @offset inside85 * the address space (using @size and @color). If the @node does not fit, it86 * tries to evict any overlapping nodes from the GTT, including any87 * neighbouring nodes if the colors do not match (to ensure guard pages between88 * differing domains). See i915_gem_evict_for_node() for the gory details89 * on the eviction algorithm. #PIN_NONBLOCK may used to prevent waiting on90 * evicting active overlapping objects, and any overlapping node that is pinned91 * or marked as unevictable will also result in failure.92 *93 * Returns: 0 on success, -ENOSPC if no suitable hole is found, -EINTR if94 * asked to wait for eviction and interrupted.95 */96int i915_gem_gtt_reserve(struct i915_address_space *vm,97 struct i915_gem_ww_ctx *ww,98 struct drm_mm_node *node,99 u64 size, u64 offset, unsigned long color,100 unsigned int flags)101{102 int err;103 104 GEM_BUG_ON(!size);105 GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));106 GEM_BUG_ON(!IS_ALIGNED(offset, I915_GTT_MIN_ALIGNMENT));107 GEM_BUG_ON(range_overflows(offset, size, vm->total));108 GEM_BUG_ON(vm == &to_gt(vm->i915)->ggtt->alias->vm);109 GEM_BUG_ON(drm_mm_node_allocated(node));110 111 node->size = size;112 node->start = offset;113 node->color = color;114 115 err = drm_mm_reserve_node(&vm->mm, node);116 if (err != -ENOSPC)117 return err;118 119 if (flags & PIN_NOEVICT)120 return -ENOSPC;121 122 err = i915_gem_evict_for_node(vm, ww, node, flags);123 if (err == 0)124 err = drm_mm_reserve_node(&vm->mm, node);125 126 return err;127}128 129static u64 random_offset(u64 start, u64 end, u64 len, u64 align)130{131 u64 range, addr;132 133 GEM_BUG_ON(range_overflows(start, len, end));134 GEM_BUG_ON(round_up(start, align) > round_down(end - len, align));135 136 range = round_down(end - len, align) - round_up(start, align);137 if (range) {138 if (sizeof(unsigned long) == sizeof(u64)) {139 addr = get_random_u64();140 } else {141 addr = get_random_u32();142 if (range > U32_MAX) {143 addr <<= 32;144 addr |= get_random_u32();145 }146 }147 div64_u64_rem(addr, range, &addr);148 start += addr;149 }150 151 return round_up(start, align);152}153 154/**155 * i915_gem_gtt_insert - insert a node into an address_space (GTT)156 * @vm: the &struct i915_address_space157 * @ww: An optional struct i915_gem_ww_ctx.158 * @node: the &struct drm_mm_node (typically i915_vma.node)159 * @size: how much space to allocate inside the GTT,160 * must be #I915_GTT_PAGE_SIZE aligned161 * @alignment: required alignment of starting offset, may be 0 but162 * if specified, this must be a power-of-two and at least163 * #I915_GTT_MIN_ALIGNMENT164 * @color: color to apply to node165 * @start: start of any range restriction inside GTT (0 for all),166 * must be #I915_GTT_PAGE_SIZE aligned167 * @end: end of any range restriction inside GTT (U64_MAX for all),168 * must be #I915_GTT_PAGE_SIZE aligned if not U64_MAX169 * @flags: control search and eviction behaviour170 *171 * i915_gem_gtt_insert() first searches for an available hole into which172 * is can insert the node. The hole address is aligned to @alignment and173 * its @size must then fit entirely within the [@start, @end] bounds. The174 * nodes on either side of the hole must match @color, or else a guard page175 * will be inserted between the two nodes (or the node evicted). If no176 * suitable hole is found, first a victim is randomly selected and tested177 * for eviction, otherwise then the LRU list of objects within the GTT178 * is scanned to find the first set of replacement nodes to create the hole.179 * Those old overlapping nodes are evicted from the GTT (and so must be180 * rebound before any future use). Any node that is currently pinned cannot181 * be evicted (see i915_vma_pin()). Similar if the node's VMA is currently182 * active and #PIN_NONBLOCK is specified, that node is also skipped when183 * searching for an eviction candidate. See i915_gem_evict_something() for184 * the gory details on the eviction algorithm.185 *186 * Returns: 0 on success, -ENOSPC if no suitable hole is found, -EINTR if187 * asked to wait for eviction and interrupted.188 */189int i915_gem_gtt_insert(struct i915_address_space *vm,190 struct i915_gem_ww_ctx *ww,191 struct drm_mm_node *node,192 u64 size, u64 alignment, unsigned long color,193 u64 start, u64 end, unsigned int flags)194{195 enum drm_mm_insert_mode mode;196 u64 offset;197 int err;198 199 lockdep_assert_held(&vm->mutex);200 201 GEM_BUG_ON(!size);202 GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));203 GEM_BUG_ON(alignment && !is_power_of_2(alignment));204 GEM_BUG_ON(alignment && !IS_ALIGNED(alignment, I915_GTT_MIN_ALIGNMENT));205 GEM_BUG_ON(start >= end);206 GEM_BUG_ON(start > 0 && !IS_ALIGNED(start, I915_GTT_PAGE_SIZE));207 GEM_BUG_ON(end < U64_MAX && !IS_ALIGNED(end, I915_GTT_PAGE_SIZE));208 GEM_BUG_ON(vm == &to_gt(vm->i915)->ggtt->alias->vm);209 GEM_BUG_ON(drm_mm_node_allocated(node));210 211 if (unlikely(range_overflows(start, size, end)))212 return -ENOSPC;213 214 if (unlikely(round_up(start, alignment) > round_down(end - size, alignment)))215 return -ENOSPC;216 217 mode = DRM_MM_INSERT_BEST;218 if (flags & PIN_HIGH)219 mode = DRM_MM_INSERT_HIGHEST;220 if (flags & PIN_MAPPABLE)221 mode = DRM_MM_INSERT_LOW;222 223 /* We only allocate in PAGE_SIZE/GTT_PAGE_SIZE (4096) chunks,224 * so we know that we always have a minimum alignment of 4096.225 * The drm_mm range manager is optimised to return results226 * with zero alignment, so where possible use the optimal227 * path.228 */229 BUILD_BUG_ON(I915_GTT_MIN_ALIGNMENT > I915_GTT_PAGE_SIZE);230 if (alignment <= I915_GTT_MIN_ALIGNMENT)231 alignment = 0;232 233 err = drm_mm_insert_node_in_range(&vm->mm, node,234 size, alignment, color,235 start, end, mode);236 if (err != -ENOSPC)237 return err;238 239 if (mode & DRM_MM_INSERT_ONCE) {240 err = drm_mm_insert_node_in_range(&vm->mm, node,241 size, alignment, color,242 start, end,243 DRM_MM_INSERT_BEST);244 if (err != -ENOSPC)245 return err;246 }247 248 if (flags & PIN_NOEVICT)249 return -ENOSPC;250 251 /*252 * No free space, pick a slot at random.253 *254 * There is a pathological case here using a GTT shared between255 * mmap and GPU (i.e. ggtt/aliasing_ppgtt but not full-ppgtt):256 *257 * |<-- 256 MiB aperture -->||<-- 1792 MiB unmappable -->|258 * (64k objects) (448k objects)259 *260 * Now imagine that the eviction LRU is ordered top-down (just because261 * pathology meets real life), and that we need to evict an object to262 * make room inside the aperture. The eviction scan then has to walk263 * the 448k list before it finds one within range. And now imagine that264 * it has to search for a new hole between every byte inside the memcpy,265 * for several simultaneous clients.266 *267 * On a full-ppgtt system, if we have run out of available space, there268 * will be lots and lots of objects in the eviction list! Again,269 * searching that LRU list may be slow if we are also applying any270 * range restrictions (e.g. restriction to low 4GiB) and so, for271 * simplicity and similarilty between different GTT, try the single272 * random replacement first.273 */274 offset = random_offset(start, end,275 size, alignment ?: I915_GTT_MIN_ALIGNMENT);276 err = i915_gem_gtt_reserve(vm, ww, node, size, offset, color, flags);277 if (err != -ENOSPC)278 return err;279 280 if (flags & PIN_NOSEARCH)281 return -ENOSPC;282 283 /* Randomly selected placement is pinned, do a search */284 err = i915_gem_evict_something(vm, ww, size, alignment, color,285 start, end, flags);286 if (err)287 return err;288 289 return drm_mm_insert_node_in_range(&vm->mm, node,290 size, alignment, color,291 start, end, DRM_MM_INSERT_EVICT);292}293 294#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)295#include "selftests/i915_gem_gtt.c"296#endif297