1 /* 2 * Copyright(c) 2011-2015 Intel Corporation. All rights reserved. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 * SOFTWARE. 22 */ 23 24 #include "i915_vgpu.h" 25 26 /** 27 * DOC: Intel GVT-g guest support 28 * 29 * Intel GVT-g is a graphics virtualization technology which shares the 30 * GPU among multiple virtual machines on a time-sharing basis. Each 31 * virtual machine is presented a virtual GPU (vGPU), which has equivalent 32 * features as the underlying physical GPU (pGPU), so i915 driver can run 33 * seamlessly in a virtual machine. This file provides vGPU specific 34 * optimizations when running in a virtual machine, to reduce the complexity 35 * of vGPU emulation and to improve the overall performance. 36 * 37 * A primary function introduced here is so-called "address space ballooning" 38 * technique. Intel GVT-g partitions global graphics memory among multiple VMs, 39 * so each VM can directly access a portion of the memory without hypervisor's 40 * intervention, e.g. filling textures or queuing commands. However with the 41 * partitioning an unmodified i915 driver would assume a smaller graphics 42 * memory starting from address ZERO, then requires vGPU emulation module to 43 * translate the graphics address between 'guest view' and 'host view', for 44 * all registers and command opcodes which contain a graphics memory address. 45 * To reduce the complexity, Intel GVT-g introduces "address space ballooning", 46 * by telling the exact partitioning knowledge to each guest i915 driver, which 47 * then reserves and prevents non-allocated portions from allocation. Thus vGPU 48 * emulation module only needs to scan and validate graphics addresses without 49 * complexity of address translation. 50 * 51 */ 52 53 /** 54 * i915_detect_vgpu - detect virtual GPU 55 * @dev_priv: i915 device private 56 * 57 * This function is called at the initialization stage, to detect whether 58 * running on a vGPU. 59 */ 60 void i915_detect_vgpu(struct drm_i915_private *dev_priv) 61 { 62 struct pci_dev *pdev = dev_priv->drm.pdev; 63 u64 magic; 64 u16 version_major; 65 void __iomem *shared_area; 66 67 BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE); 68 69 /* 70 * This is called before we setup the main MMIO BAR mappings used via 71 * the uncore structure, so we need to access the BAR directly. Since 72 * we do not support VGT on older gens, return early so we don't have 73 * to consider differently numbered or sized MMIO bars 74 */ 75 if (INTEL_GEN(dev_priv) < 6) 76 return; 77 78 shared_area = pci_iomap_range(pdev, 0, VGT_PVINFO_PAGE, VGT_PVINFO_SIZE); 79 if (!shared_area) { 80 drm_err(&dev_priv->drm, 81 "failed to map MMIO bar to check for VGT\n"); 82 return; 83 } 84 85 magic = readq(shared_area + vgtif_offset(magic)); 86 if (magic != VGT_MAGIC) 87 goto out; 88 89 version_major = readw(shared_area + vgtif_offset(version_major)); 90 if (version_major < VGT_VERSION_MAJOR) { 91 drm_info(&dev_priv->drm, "VGT interface version mismatch!\n"); 92 goto out; 93 } 94 95 dev_priv->vgpu.caps = readl(shared_area + vgtif_offset(vgt_caps)); 96 97 dev_priv->vgpu.active = true; 98 mutex_init(&dev_priv->vgpu.lock); 99 drm_info(&dev_priv->drm, "Virtual GPU for Intel GVT-g detected.\n"); 100 101 out: 102 pci_iounmap(pdev, shared_area); 103 } 104 105 bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *dev_priv) 106 { 107 return dev_priv->vgpu.caps & VGT_CAPS_FULL_PPGTT; 108 } 109 110 struct _balloon_info_ { 111 /* 112 * There are up to 2 regions per mappable/unmappable graphic 113 * memory that might be ballooned. Here, index 0/1 is for mappable 114 * graphic memory, 2/3 for unmappable graphic memory. 115 */ 116 struct drm_mm_node space[4]; 117 }; 118 119 static struct _balloon_info_ bl_info; 120 121 static void vgt_deballoon_space(struct i915_ggtt *ggtt, 122 struct drm_mm_node *node) 123 { 124 struct drm_i915_private *dev_priv = ggtt->vm.i915; 125 if (!drm_mm_node_allocated(node)) 126 return; 127 128 drm_dbg(&dev_priv->drm, 129 "deballoon space: range [0x%llx - 0x%llx] %llu KiB.\n", 130 node->start, 131 node->start + node->size, 132 node->size / 1024); 133 134 ggtt->vm.reserved -= node->size; 135 drm_mm_remove_node(node); 136 } 137 138 /** 139 * intel_vgt_deballoon - deballoon reserved graphics address trunks 140 * @ggtt: the global GGTT from which we reserved earlier 141 * 142 * This function is called to deallocate the ballooned-out graphic memory, when 143 * driver is unloaded or when ballooning fails. 144 */ 145 void intel_vgt_deballoon(struct i915_ggtt *ggtt) 146 { 147 struct drm_i915_private *dev_priv = ggtt->vm.i915; 148 int i; 149 150 if (!intel_vgpu_active(ggtt->vm.i915)) 151 return; 152 153 drm_dbg(&dev_priv->drm, "VGT deballoon.\n"); 154 155 for (i = 0; i < 4; i++) 156 vgt_deballoon_space(ggtt, &bl_info.space[i]); 157 } 158 159 static int vgt_balloon_space(struct i915_ggtt *ggtt, 160 struct drm_mm_node *node, 161 unsigned long start, unsigned long end) 162 { 163 struct drm_i915_private *dev_priv = ggtt->vm.i915; 164 unsigned long size = end - start; 165 int ret; 166 167 if (start >= end) 168 return -EINVAL; 169 170 drm_info(&dev_priv->drm, 171 "balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n", 172 start, end, size / 1024); 173 ret = i915_gem_gtt_reserve(&ggtt->vm, node, 174 size, start, I915_COLOR_UNEVICTABLE, 175 0); 176 if (!ret) 177 ggtt->vm.reserved += size; 178 179 return ret; 180 } 181 182 /** 183 * intel_vgt_balloon - balloon out reserved graphics address trunks 184 * @ggtt: the global GGTT from which to reserve 185 * 186 * This function is called at the initialization stage, to balloon out the 187 * graphic address space allocated to other vGPUs, by marking these spaces as 188 * reserved. The ballooning related knowledge(starting address and size of 189 * the mappable/unmappable graphic memory) is described in the vgt_if structure 190 * in a reserved mmio range. 191 * 192 * To give an example, the drawing below depicts one typical scenario after 193 * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned 194 * out each for the mappable and the non-mappable part. From the vGPU1 point of 195 * view, the total size is the same as the physical one, with the start address 196 * of its graphic space being zero. Yet there are some portions ballooned out( 197 * the shadow part, which are marked as reserved by drm allocator). From the 198 * host point of view, the graphic address space is partitioned by multiple 199 * vGPUs in different VMs. :: 200 * 201 * vGPU1 view Host view 202 * 0 ------> +-----------+ +-----------+ 203 * ^ |###########| | vGPU3 | 204 * | |###########| +-----------+ 205 * | |###########| | vGPU2 | 206 * | +-----------+ +-----------+ 207 * mappable GM | available | ==> | vGPU1 | 208 * | +-----------+ +-----------+ 209 * | |###########| | | 210 * v |###########| | Host | 211 * +=======+===========+ +===========+ 212 * ^ |###########| | vGPU3 | 213 * | |###########| +-----------+ 214 * | |###########| | vGPU2 | 215 * | +-----------+ +-----------+ 216 * unmappable GM | available | ==> | vGPU1 | 217 * | +-----------+ +-----------+ 218 * | |###########| | | 219 * | |###########| | Host | 220 * v |###########| | | 221 * total GM size ------> +-----------+ +-----------+ 222 * 223 * Returns: 224 * zero on success, non-zero if configuration invalid or ballooning failed 225 */ 226 int intel_vgt_balloon(struct i915_ggtt *ggtt) 227 { 228 struct drm_i915_private *dev_priv = ggtt->vm.i915; 229 struct intel_uncore *uncore = &dev_priv->uncore; 230 unsigned long ggtt_end = ggtt->vm.total; 231 232 unsigned long mappable_base, mappable_size, mappable_end; 233 unsigned long unmappable_base, unmappable_size, unmappable_end; 234 int ret; 235 236 if (!intel_vgpu_active(ggtt->vm.i915)) 237 return 0; 238 239 mappable_base = 240 intel_uncore_read(uncore, vgtif_reg(avail_rs.mappable_gmadr.base)); 241 mappable_size = 242 intel_uncore_read(uncore, vgtif_reg(avail_rs.mappable_gmadr.size)); 243 unmappable_base = 244 intel_uncore_read(uncore, vgtif_reg(avail_rs.nonmappable_gmadr.base)); 245 unmappable_size = 246 intel_uncore_read(uncore, vgtif_reg(avail_rs.nonmappable_gmadr.size)); 247 248 mappable_end = mappable_base + mappable_size; 249 unmappable_end = unmappable_base + unmappable_size; 250 251 drm_info(&dev_priv->drm, "VGT ballooning configuration:\n"); 252 drm_info(&dev_priv->drm, 253 "Mappable graphic memory: base 0x%lx size %ldKiB\n", 254 mappable_base, mappable_size / 1024); 255 drm_info(&dev_priv->drm, 256 "Unmappable graphic memory: base 0x%lx size %ldKiB\n", 257 unmappable_base, unmappable_size / 1024); 258 259 if (mappable_end > ggtt->mappable_end || 260 unmappable_base < ggtt->mappable_end || 261 unmappable_end > ggtt_end) { 262 drm_err(&dev_priv->drm, "Invalid ballooning configuration!\n"); 263 return -EINVAL; 264 } 265 266 /* Unmappable graphic memory ballooning */ 267 if (unmappable_base > ggtt->mappable_end) { 268 ret = vgt_balloon_space(ggtt, &bl_info.space[2], 269 ggtt->mappable_end, unmappable_base); 270 271 if (ret) 272 goto err; 273 } 274 275 if (unmappable_end < ggtt_end) { 276 ret = vgt_balloon_space(ggtt, &bl_info.space[3], 277 unmappable_end, ggtt_end); 278 if (ret) 279 goto err_upon_mappable; 280 } 281 282 /* Mappable graphic memory ballooning */ 283 if (mappable_base) { 284 ret = vgt_balloon_space(ggtt, &bl_info.space[0], 285 0, mappable_base); 286 287 if (ret) 288 goto err_upon_unmappable; 289 } 290 291 if (mappable_end < ggtt->mappable_end) { 292 ret = vgt_balloon_space(ggtt, &bl_info.space[1], 293 mappable_end, ggtt->mappable_end); 294 295 if (ret) 296 goto err_below_mappable; 297 } 298 299 drm_info(&dev_priv->drm, "VGT balloon successfully\n"); 300 return 0; 301 302 err_below_mappable: 303 vgt_deballoon_space(ggtt, &bl_info.space[0]); 304 err_upon_unmappable: 305 vgt_deballoon_space(ggtt, &bl_info.space[3]); 306 err_upon_mappable: 307 vgt_deballoon_space(ggtt, &bl_info.space[2]); 308 err: 309 drm_err(&dev_priv->drm, "VGT balloon fail\n"); 310 return ret; 311 } 312