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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: drm device * | |
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_device *dev) | |
62 | { | |
63 | struct drm_i915_private *dev_priv = to_i915(dev); | |
64 | uint64_t magic; | |
65 | uint32_t version; | |
66 | ||
67 | BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE); | |
68 | ||
69 | if (!IS_HASWELL(dev)) | |
70 | return; | |
71 | ||
72 | magic = readq(dev_priv->regs + vgtif_reg(magic)); | |
73 | if (magic != VGT_MAGIC) | |
74 | return; | |
75 | ||
76 | version = INTEL_VGT_IF_VERSION_ENCODE( | |
77 | readw(dev_priv->regs + vgtif_reg(version_major)), | |
78 | readw(dev_priv->regs + vgtif_reg(version_minor))); | |
79 | if (version != INTEL_VGT_IF_VERSION) { | |
80 | DRM_INFO("VGT interface version mismatch!\n"); | |
81 | return; | |
82 | } | |
83 | ||
84 | dev_priv->vgpu.active = true; | |
85 | DRM_INFO("Virtual GPU for Intel GVT-g detected.\n"); | |
86 | } |