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 "intel_drv.h" 25 #include "i915_vgpu.h" 26 27 /** 28 * DOC: Intel GVT-g guest support 29 * 30 * Intel GVT-g is a graphics virtualization technology which shares the 31 * GPU among multiple virtual machines on a time-sharing basis. Each 32 * virtual machine is presented a virtual GPU (vGPU), which has equivalent 33 * features as the underlying physical GPU (pGPU), so i915 driver can run 34 * seamlessly in a virtual machine. This file provides vGPU specific 35 * optimizations when running in a virtual machine, to reduce the complexity 36 * of vGPU emulation and to improve the overall performance. 37 * 38 * A primary function introduced here is so-called "address space ballooning" 39 * technique. Intel GVT-g partitions global graphics memory among multiple VMs, 40 * so each VM can directly access a portion of the memory without hypervisor's 41 * intervention, e.g. filling textures or queuing commands. However with the 42 * partitioning an unmodified i915 driver would assume a smaller graphics 43 * memory starting from address ZERO, then requires vGPU emulation module to 44 * translate the graphics address between 'guest view' and 'host view', for 45 * all registers and command opcodes which contain a graphics memory address. 46 * To reduce the complexity, Intel GVT-g introduces "address space ballooning", 47 * by telling the exact partitioning knowledge to each guest i915 driver, which 48 * then reserves and prevents non-allocated portions from allocation. Thus vGPU 49 * emulation module only needs to scan and validate graphics addresses without 50 * complexity of address translation. 51 * 52 */ 53 54 /** 55 * i915_check_vgpu - detect virtual GPU 56 * @dev_priv: i915 device private 57 * 58 * This function is called at the initialization stage, to detect whether 59 * running on a vGPU. 60 */ 61 void i915_check_vgpu(struct drm_i915_private *dev_priv) 62 { 63 uint64_t magic; 64 uint32_t version; 65 66 BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE); 67 68 magic = __raw_i915_read64(dev_priv, vgtif_reg(magic)); 69 if (magic != VGT_MAGIC) 70 return; 71 72 version = INTEL_VGT_IF_VERSION_ENCODE( 73 __raw_i915_read16(dev_priv, vgtif_reg(version_major)), 74 __raw_i915_read16(dev_priv, vgtif_reg(version_minor))); 75 if (version != INTEL_VGT_IF_VERSION) { 76 DRM_INFO("VGT interface version mismatch!\n"); 77 return; 78 } 79 80 dev_priv->vgpu.active = true; 81 DRM_INFO("Virtual GPU for Intel GVT-g detected.\n"); 82 } 83 84 struct _balloon_info_ { 85 /* 86 * There are up to 2 regions per mappable/unmappable graphic 87 * memory that might be ballooned. Here, index 0/1 is for mappable 88 * graphic memory, 2/3 for unmappable graphic memory. 89 */ 90 struct drm_mm_node space[4]; 91 }; 92 93 static struct _balloon_info_ bl_info; 94 95 /** 96 * intel_vgt_deballoon - deballoon reserved graphics address trunks 97 * 98 * This function is called to deallocate the ballooned-out graphic memory, when 99 * driver is unloaded or when ballooning fails. 100 */ 101 void intel_vgt_deballoon(struct drm_i915_private *dev_priv) 102 { 103 int i; 104 105 if (!intel_vgpu_active(dev_priv)) 106 return; 107 108 DRM_DEBUG("VGT deballoon.\n"); 109 110 for (i = 0; i < 4; i++) { 111 if (bl_info.space[i].allocated) 112 drm_mm_remove_node(&bl_info.space[i]); 113 } 114 115 memset(&bl_info, 0, sizeof(bl_info)); 116 } 117 118 static int vgt_balloon_space(struct drm_mm *mm, 119 struct drm_mm_node *node, 120 unsigned long start, unsigned long end) 121 { 122 unsigned long size = end - start; 123 124 if (start == end) 125 return -EINVAL; 126 127 DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n", 128 start, end, size / 1024); 129 130 node->start = start; 131 node->size = size; 132 133 return drm_mm_reserve_node(mm, node); 134 } 135 136 /** 137 * intel_vgt_balloon - balloon out reserved graphics address trunks 138 * @dev: drm device 139 * 140 * This function is called at the initialization stage, to balloon out the 141 * graphic address space allocated to other vGPUs, by marking these spaces as 142 * reserved. The ballooning related knowledge(starting address and size of 143 * the mappable/unmappable graphic memory) is described in the vgt_if structure 144 * in a reserved mmio range. 145 * 146 * To give an example, the drawing below depicts one typical scenario after 147 * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned 148 * out each for the mappable and the non-mappable part. From the vGPU1 point of 149 * view, the total size is the same as the physical one, with the start address 150 * of its graphic space being zero. Yet there are some portions ballooned out( 151 * the shadow part, which are marked as reserved by drm allocator). From the 152 * host point of view, the graphic address space is partitioned by multiple 153 * vGPUs in different VMs. :: 154 * 155 * vGPU1 view Host view 156 * 0 ------> +-----------+ +-----------+ 157 * ^ |###########| | vGPU3 | 158 * | |###########| +-----------+ 159 * | |###########| | vGPU2 | 160 * | +-----------+ +-----------+ 161 * mappable GM | available | ==> | vGPU1 | 162 * | +-----------+ +-----------+ 163 * | |###########| | | 164 * v |###########| | Host | 165 * +=======+===========+ +===========+ 166 * ^ |###########| | vGPU3 | 167 * | |###########| +-----------+ 168 * | |###########| | vGPU2 | 169 * | +-----------+ +-----------+ 170 * unmappable GM | available | ==> | vGPU1 | 171 * | +-----------+ +-----------+ 172 * | |###########| | | 173 * | |###########| | Host | 174 * v |###########| | | 175 * total GM size ------> +-----------+ +-----------+ 176 * 177 * Returns: 178 * zero on success, non-zero if configuration invalid or ballooning failed 179 */ 180 int intel_vgt_balloon(struct drm_i915_private *dev_priv) 181 { 182 struct i915_ggtt *ggtt = &dev_priv->ggtt; 183 unsigned long ggtt_end = ggtt->base.start + ggtt->base.total; 184 185 unsigned long mappable_base, mappable_size, mappable_end; 186 unsigned long unmappable_base, unmappable_size, unmappable_end; 187 int ret; 188 189 if (!intel_vgpu_active(dev_priv)) 190 return 0; 191 192 mappable_base = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.base)); 193 mappable_size = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.size)); 194 unmappable_base = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.base)); 195 unmappable_size = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.size)); 196 197 mappable_end = mappable_base + mappable_size; 198 unmappable_end = unmappable_base + unmappable_size; 199 200 DRM_INFO("VGT ballooning configuration:\n"); 201 DRM_INFO("Mappable graphic memory: base 0x%lx size %ldKiB\n", 202 mappable_base, mappable_size / 1024); 203 DRM_INFO("Unmappable graphic memory: base 0x%lx size %ldKiB\n", 204 unmappable_base, unmappable_size / 1024); 205 206 if (mappable_base < ggtt->base.start || 207 mappable_end > ggtt->mappable_end || 208 unmappable_base < ggtt->mappable_end || 209 unmappable_end > ggtt_end) { 210 DRM_ERROR("Invalid ballooning configuration!\n"); 211 return -EINVAL; 212 } 213 214 /* Unmappable graphic memory ballooning */ 215 if (unmappable_base > ggtt->mappable_end) { 216 ret = vgt_balloon_space(&ggtt->base.mm, 217 &bl_info.space[2], 218 ggtt->mappable_end, 219 unmappable_base); 220 221 if (ret) 222 goto err; 223 } 224 225 /* 226 * No need to partition out the last physical page, 227 * because it is reserved to the guard page. 228 */ 229 if (unmappable_end < ggtt_end - PAGE_SIZE) { 230 ret = vgt_balloon_space(&ggtt->base.mm, 231 &bl_info.space[3], 232 unmappable_end, 233 ggtt_end - PAGE_SIZE); 234 if (ret) 235 goto err; 236 } 237 238 /* Mappable graphic memory ballooning */ 239 if (mappable_base > ggtt->base.start) { 240 ret = vgt_balloon_space(&ggtt->base.mm, 241 &bl_info.space[0], 242 ggtt->base.start, mappable_base); 243 244 if (ret) 245 goto err; 246 } 247 248 if (mappable_end < ggtt->mappable_end) { 249 ret = vgt_balloon_space(&ggtt->base.mm, 250 &bl_info.space[1], 251 mappable_end, 252 ggtt->mappable_end); 253 254 if (ret) 255 goto err; 256 } 257 258 DRM_INFO("VGT balloon successfully\n"); 259 return 0; 260 261 err: 262 DRM_ERROR("VGT balloon fail\n"); 263 intel_vgt_deballoon(dev_priv); 264 return ret; 265 } 266