blob: 995a6003ed7836ad99880f040abf126a57240287 [file] [log] [blame]
Yu Zhangcf9d2892015-02-10 19:05:47 +08001/*
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 */
61void 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}