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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 | u64 magic; | |
64 | u16 version_major; | |
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_major = __raw_i915_read16(dev_priv, vgtif_reg(version_major)); | |
73 | if (version_major < VGT_VERSION_MAJOR) { | |
74 | DRM_INFO("VGT interface version mismatch!\n"); | |
75 | return; | |
76 | } | |
77 | ||
78 | dev_priv->vgpu.active = true; | |
79 | DRM_INFO("Virtual GPU for Intel GVT-g detected.\n"); | |
80 | } | |
81 | ||
82 | struct _balloon_info_ { | |
83 | /* | |
84 | * There are up to 2 regions per mappable/unmappable graphic | |
85 | * memory that might be ballooned. Here, index 0/1 is for mappable | |
86 | * graphic memory, 2/3 for unmappable graphic memory. | |
87 | */ | |
88 | struct drm_mm_node space[4]; | |
89 | }; | |
90 | ||
91 | static struct _balloon_info_ bl_info; | |
92 | ||
93 | /** | |
94 | * intel_vgt_deballoon - deballoon reserved graphics address trunks | |
95 | * @dev_priv: i915 device private data | |
96 | * | |
97 | * This function is called to deallocate the ballooned-out graphic memory, when | |
98 | * driver is unloaded or when ballooning fails. | |
99 | */ | |
100 | void intel_vgt_deballoon(struct drm_i915_private *dev_priv) | |
101 | { | |
102 | int i; | |
103 | ||
104 | if (!intel_vgpu_active(dev_priv)) | |
105 | return; | |
106 | ||
107 | DRM_DEBUG("VGT deballoon.\n"); | |
108 | ||
109 | for (i = 0; i < 4; i++) { | |
110 | if (bl_info.space[i].allocated) | |
111 | drm_mm_remove_node(&bl_info.space[i]); | |
112 | } | |
113 | ||
114 | memset(&bl_info, 0, sizeof(bl_info)); | |
115 | } | |
116 | ||
117 | static int vgt_balloon_space(struct i915_ggtt *ggtt, | |
118 | struct drm_mm_node *node, | |
119 | unsigned long start, unsigned long end) | |
120 | { | |
121 | unsigned long size = end - start; | |
122 | ||
123 | if (start >= end) | |
124 | return -EINVAL; | |
125 | ||
126 | DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n", | |
127 | start, end, size / 1024); | |
128 | return i915_gem_gtt_reserve(&ggtt->base, node, | |
129 | size, start, I915_COLOR_UNEVICTABLE, | |
130 | 0); | |
131 | } | |
132 | ||
133 | /** | |
134 | * intel_vgt_balloon - balloon out reserved graphics address trunks | |
135 | * @dev_priv: i915 device private data | |
136 | * | |
137 | * This function is called at the initialization stage, to balloon out the | |
138 | * graphic address space allocated to other vGPUs, by marking these spaces as | |
139 | * reserved. The ballooning related knowledge(starting address and size of | |
140 | * the mappable/unmappable graphic memory) is described in the vgt_if structure | |
141 | * in a reserved mmio range. | |
142 | * | |
143 | * To give an example, the drawing below depicts one typical scenario after | |
144 | * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned | |
145 | * out each for the mappable and the non-mappable part. From the vGPU1 point of | |
146 | * view, the total size is the same as the physical one, with the start address | |
147 | * of its graphic space being zero. Yet there are some portions ballooned out( | |
148 | * the shadow part, which are marked as reserved by drm allocator). From the | |
149 | * host point of view, the graphic address space is partitioned by multiple | |
150 | * vGPUs in different VMs. :: | |
151 | * | |
152 | * vGPU1 view Host view | |
153 | * 0 ------> +-----------+ +-----------+ | |
154 | * ^ |###########| | vGPU3 | | |
155 | * | |###########| +-----------+ | |
156 | * | |###########| | vGPU2 | | |
157 | * | +-----------+ +-----------+ | |
158 | * mappable GM | available | ==> | vGPU1 | | |
159 | * | +-----------+ +-----------+ | |
160 | * | |###########| | | | |
161 | * v |###########| | Host | | |
162 | * +=======+===========+ +===========+ | |
163 | * ^ |###########| | vGPU3 | | |
164 | * | |###########| +-----------+ | |
165 | * | |###########| | vGPU2 | | |
166 | * | +-----------+ +-----------+ | |
167 | * unmappable GM | available | ==> | vGPU1 | | |
168 | * | +-----------+ +-----------+ | |
169 | * | |###########| | | | |
170 | * | |###########| | Host | | |
171 | * v |###########| | | | |
172 | * total GM size ------> +-----------+ +-----------+ | |
173 | * | |
174 | * Returns: | |
175 | * zero on success, non-zero if configuration invalid or ballooning failed | |
176 | */ | |
177 | int intel_vgt_balloon(struct drm_i915_private *dev_priv) | |
178 | { | |
179 | struct i915_ggtt *ggtt = &dev_priv->ggtt; | |
180 | unsigned long ggtt_end = ggtt->base.total; | |
181 | ||
182 | unsigned long mappable_base, mappable_size, mappable_end; | |
183 | unsigned long unmappable_base, unmappable_size, unmappable_end; | |
184 | int ret; | |
185 | ||
186 | if (!intel_vgpu_active(dev_priv)) | |
187 | return 0; | |
188 | ||
189 | mappable_base = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.base)); | |
190 | mappable_size = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.size)); | |
191 | unmappable_base = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.base)); | |
192 | unmappable_size = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.size)); | |
193 | ||
194 | mappable_end = mappable_base + mappable_size; | |
195 | unmappable_end = unmappable_base + unmappable_size; | |
196 | ||
197 | DRM_INFO("VGT ballooning configuration:\n"); | |
198 | DRM_INFO("Mappable graphic memory: base 0x%lx size %ldKiB\n", | |
199 | mappable_base, mappable_size / 1024); | |
200 | DRM_INFO("Unmappable graphic memory: base 0x%lx size %ldKiB\n", | |
201 | unmappable_base, unmappable_size / 1024); | |
202 | ||
203 | if (mappable_end > ggtt->mappable_end || | |
204 | unmappable_base < ggtt->mappable_end || | |
205 | unmappable_end > ggtt_end) { | |
206 | DRM_ERROR("Invalid ballooning configuration!\n"); | |
207 | return -EINVAL; | |
208 | } | |
209 | ||
210 | /* Unmappable graphic memory ballooning */ | |
211 | if (unmappable_base > ggtt->mappable_end) { | |
212 | ret = vgt_balloon_space(ggtt, &bl_info.space[2], | |
213 | ggtt->mappable_end, unmappable_base); | |
214 | ||
215 | if (ret) | |
216 | goto err; | |
217 | } | |
218 | ||
219 | if (unmappable_end < ggtt_end) { | |
220 | ret = vgt_balloon_space(ggtt, &bl_info.space[3], | |
221 | unmappable_end, ggtt_end); | |
222 | if (ret) | |
223 | goto err; | |
224 | } | |
225 | ||
226 | /* Mappable graphic memory ballooning */ | |
227 | if (mappable_base) { | |
228 | ret = vgt_balloon_space(ggtt, &bl_info.space[0], | |
229 | 0, mappable_base); | |
230 | ||
231 | if (ret) | |
232 | goto err; | |
233 | } | |
234 | ||
235 | if (mappable_end < ggtt->mappable_end) { | |
236 | ret = vgt_balloon_space(ggtt, &bl_info.space[1], | |
237 | mappable_end, ggtt->mappable_end); | |
238 | ||
239 | if (ret) | |
240 | goto err; | |
241 | } | |
242 | ||
243 | DRM_INFO("VGT balloon successfully\n"); | |
244 | return 0; | |
245 | ||
246 | err: | |
247 | DRM_ERROR("VGT balloon fail\n"); | |
248 | intel_vgt_deballoon(dev_priv); | |
249 | return ret; | |
250 | } |