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_ERROR("failed to map MMIO bar to check for VGT\n"); 81 return; 82 } 83 84 magic = readq(shared_area + vgtif_offset(magic)); 85 if (magic != VGT_MAGIC) 86 goto out; 87 88 version_major = readw(shared_area + vgtif_offset(version_major)); 89 if (version_major < VGT_VERSION_MAJOR) { 90 DRM_INFO("VGT interface version mismatch!\n"); 91 goto out; 92 } 93 94 dev_priv->vgpu.caps = readl(shared_area + vgtif_offset(vgt_caps)); 95 96 dev_priv->vgpu.active = true; 97 mutex_init(&dev_priv->vgpu.lock); 98 DRM_INFO("Virtual GPU for Intel GVT-g detected.\n"); 99 100 out: 101 pci_iounmap(pdev, shared_area); 102 } 103 104 bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *dev_priv) 105 { 106 return dev_priv->vgpu.caps & VGT_CAPS_FULL_PPGTT; 107 } 108 109 struct _balloon_info_ { 110 /* 111 * There are up to 2 regions per mappable/unmappable graphic 112 * memory that might be ballooned. Here, index 0/1 is for mappable 113 * graphic memory, 2/3 for unmappable graphic memory. 114 */ 115 struct drm_mm_node space[4]; 116 }; 117 118 static struct _balloon_info_ bl_info; 119 120 static void vgt_deballoon_space(struct i915_ggtt *ggtt, 121 struct drm_mm_node *node) 122 { 123 if (!drm_mm_node_allocated(node)) 124 return; 125 126 DRM_DEBUG_DRIVER("deballoon space: range [0x%llx - 0x%llx] %llu KiB.\n", 127 node->start, 128 node->start + node->size, 129 node->size / 1024); 130 131 ggtt->vm.reserved -= node->size; 132 drm_mm_remove_node(node); 133 } 134 135 /** 136 * intel_vgt_deballoon - deballoon reserved graphics address trunks 137 * @ggtt: the global GGTT from which we reserved earlier 138 * 139 * This function is called to deallocate the ballooned-out graphic memory, when 140 * driver is unloaded or when ballooning fails. 141 */ 142 void intel_vgt_deballoon(struct i915_ggtt *ggtt) 143 { 144 int i; 145 146 if (!intel_vgpu_active(ggtt->vm.i915)) 147 return; 148 149 DRM_DEBUG("VGT deballoon.\n"); 150 151 for (i = 0; i < 4; i++) 152 vgt_deballoon_space(ggtt, &bl_info.space[i]); 153 } 154 155 static int vgt_balloon_space(struct i915_ggtt *ggtt, 156 struct drm_mm_node *node, 157 unsigned long start, unsigned long end) 158 { 159 unsigned long size = end - start; 160 int ret; 161 162 if (start >= end) 163 return -EINVAL; 164 165 DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n", 166 start, end, size / 1024); 167 ret = i915_gem_gtt_reserve(&ggtt->vm, node, 168 size, start, I915_COLOR_UNEVICTABLE, 169 0); 170 if (!ret) 171 ggtt->vm.reserved += size; 172 173 return ret; 174 } 175 176 /** 177 * intel_vgt_balloon - balloon out reserved graphics address trunks 178 * @ggtt: the global GGTT from which to reserve 179 * 180 * This function is called at the initialization stage, to balloon out the 181 * graphic address space allocated to other vGPUs, by marking these spaces as 182 * reserved. The ballooning related knowledge(starting address and size of 183 * the mappable/unmappable graphic memory) is described in the vgt_if structure 184 * in a reserved mmio range. 185 * 186 * To give an example, the drawing below depicts one typical scenario after 187 * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned 188 * out each for the mappable and the non-mappable part. From the vGPU1 point of 189 * view, the total size is the same as the physical one, with the start address 190 * of its graphic space being zero. Yet there are some portions ballooned out( 191 * the shadow part, which are marked as reserved by drm allocator). From the 192 * host point of view, the graphic address space is partitioned by multiple 193 * vGPUs in different VMs. :: 194 * 195 * vGPU1 view Host view 196 * 0 ------> +-----------+ +-----------+ 197 * ^ |###########| | vGPU3 | 198 * | |###########| +-----------+ 199 * | |###########| | vGPU2 | 200 * | +-----------+ +-----------+ 201 * mappable GM | available | ==> | vGPU1 | 202 * | +-----------+ +-----------+ 203 * | |###########| | | 204 * v |###########| | Host | 205 * +=======+===========+ +===========+ 206 * ^ |###########| | vGPU3 | 207 * | |###########| +-----------+ 208 * | |###########| | vGPU2 | 209 * | +-----------+ +-----------+ 210 * unmappable GM | available | ==> | vGPU1 | 211 * | +-----------+ +-----------+ 212 * | |###########| | | 213 * | |###########| | Host | 214 * v |###########| | | 215 * total GM size ------> +-----------+ +-----------+ 216 * 217 * Returns: 218 * zero on success, non-zero if configuration invalid or ballooning failed 219 */ 220 int intel_vgt_balloon(struct i915_ggtt *ggtt) 221 { 222 struct intel_uncore *uncore = &ggtt->vm.i915->uncore; 223 unsigned long ggtt_end = ggtt->vm.total; 224 225 unsigned long mappable_base, mappable_size, mappable_end; 226 unsigned long unmappable_base, unmappable_size, unmappable_end; 227 int ret; 228 229 if (!intel_vgpu_active(ggtt->vm.i915)) 230 return 0; 231 232 mappable_base = 233 intel_uncore_read(uncore, vgtif_reg(avail_rs.mappable_gmadr.base)); 234 mappable_size = 235 intel_uncore_read(uncore, vgtif_reg(avail_rs.mappable_gmadr.size)); 236 unmappable_base = 237 intel_uncore_read(uncore, vgtif_reg(avail_rs.nonmappable_gmadr.base)); 238 unmappable_size = 239 intel_uncore_read(uncore, vgtif_reg(avail_rs.nonmappable_gmadr.size)); 240 241 mappable_end = mappable_base + mappable_size; 242 unmappable_end = unmappable_base + unmappable_size; 243 244 DRM_INFO("VGT ballooning configuration:\n"); 245 DRM_INFO("Mappable graphic memory: base 0x%lx size %ldKiB\n", 246 mappable_base, mappable_size / 1024); 247 DRM_INFO("Unmappable graphic memory: base 0x%lx size %ldKiB\n", 248 unmappable_base, unmappable_size / 1024); 249 250 if (mappable_end > ggtt->mappable_end || 251 unmappable_base < ggtt->mappable_end || 252 unmappable_end > ggtt_end) { 253 DRM_ERROR("Invalid ballooning configuration!\n"); 254 return -EINVAL; 255 } 256 257 /* Unmappable graphic memory ballooning */ 258 if (unmappable_base > ggtt->mappable_end) { 259 ret = vgt_balloon_space(ggtt, &bl_info.space[2], 260 ggtt->mappable_end, unmappable_base); 261 262 if (ret) 263 goto err; 264 } 265 266 if (unmappable_end < ggtt_end) { 267 ret = vgt_balloon_space(ggtt, &bl_info.space[3], 268 unmappable_end, ggtt_end); 269 if (ret) 270 goto err_upon_mappable; 271 } 272 273 /* Mappable graphic memory ballooning */ 274 if (mappable_base) { 275 ret = vgt_balloon_space(ggtt, &bl_info.space[0], 276 0, mappable_base); 277 278 if (ret) 279 goto err_upon_unmappable; 280 } 281 282 if (mappable_end < ggtt->mappable_end) { 283 ret = vgt_balloon_space(ggtt, &bl_info.space[1], 284 mappable_end, ggtt->mappable_end); 285 286 if (ret) 287 goto err_below_mappable; 288 } 289 290 DRM_INFO("VGT balloon successfully\n"); 291 return 0; 292 293 err_below_mappable: 294 vgt_deballoon_space(ggtt, &bl_info.space[0]); 295 err_upon_unmappable: 296 vgt_deballoon_space(ggtt, &bl_info.space[3]); 297 err_upon_mappable: 298 vgt_deballoon_space(ggtt, &bl_info.space[2]); 299 err: 300 DRM_ERROR("VGT balloon fail\n"); 301 return ret; 302 } 303