2 * Copyright(c) 2011-2015 Intel Corporation. All rights reserved.
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
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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:
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
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
24 #include "intel_drv.h"
25 #include "i915_vgpu.h"
28 * DOC: Intel GVT-g guest support
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.
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.
55 * i915_check_vgpu - detect virtual GPU
56 * @dev_priv: i915 device private
58 * This function is called at the initialization stage, to detect whether
61 void i915_check_vgpu(struct drm_i915_private
*dev_priv
)
66 BUILD_BUG_ON(sizeof(struct vgt_if
) != VGT_PVINFO_SIZE
);
68 magic
= __raw_i915_read64(dev_priv
, vgtif_reg(magic
));
69 if (magic
!= VGT_MAGIC
)
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");
80 dev_priv
->vgpu
.active
= true;
81 DRM_INFO("Virtual GPU for Intel GVT-g detected.\n");
84 struct _balloon_info_
{
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.
90 struct drm_mm_node space
[4];
93 static struct _balloon_info_ bl_info
;
96 * intel_vgt_deballoon - deballoon reserved graphics address trunks
97 * @dev_priv: i915 device private data
99 * This function is called to deallocate the ballooned-out graphic memory, when
100 * driver is unloaded or when ballooning fails.
102 void intel_vgt_deballoon(struct drm_i915_private
*dev_priv
)
106 if (!intel_vgpu_active(dev_priv
))
109 DRM_DEBUG("VGT deballoon.\n");
111 for (i
= 0; i
< 4; i
++) {
112 if (bl_info
.space
[i
].allocated
)
113 drm_mm_remove_node(&bl_info
.space
[i
]);
116 memset(&bl_info
, 0, sizeof(bl_info
));
119 static int vgt_balloon_space(struct drm_mm
*mm
,
120 struct drm_mm_node
*node
,
121 unsigned long start
, unsigned long end
)
123 unsigned long size
= end
- start
;
128 DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n",
129 start
, end
, size
/ 1024);
134 return drm_mm_reserve_node(mm
, node
);
138 * intel_vgt_balloon - balloon out reserved graphics address trunks
139 * @dev_priv: i915 device private data
141 * This function is called at the initialization stage, to balloon out the
142 * graphic address space allocated to other vGPUs, by marking these spaces as
143 * reserved. The ballooning related knowledge(starting address and size of
144 * the mappable/unmappable graphic memory) is described in the vgt_if structure
145 * in a reserved mmio range.
147 * To give an example, the drawing below depicts one typical scenario after
148 * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned
149 * out each for the mappable and the non-mappable part. From the vGPU1 point of
150 * view, the total size is the same as the physical one, with the start address
151 * of its graphic space being zero. Yet there are some portions ballooned out(
152 * the shadow part, which are marked as reserved by drm allocator). From the
153 * host point of view, the graphic address space is partitioned by multiple
154 * vGPUs in different VMs. ::
156 * vGPU1 view Host view
157 * 0 ------> +-----------+ +-----------+
158 * ^ |###########| | vGPU3 |
159 * | |###########| +-----------+
160 * | |###########| | vGPU2 |
161 * | +-----------+ +-----------+
162 * mappable GM | available | ==> | vGPU1 |
163 * | +-----------+ +-----------+
164 * | |###########| | |
165 * v |###########| | Host |
166 * +=======+===========+ +===========+
167 * ^ |###########| | vGPU3 |
168 * | |###########| +-----------+
169 * | |###########| | vGPU2 |
170 * | +-----------+ +-----------+
171 * unmappable GM | available | ==> | vGPU1 |
172 * | +-----------+ +-----------+
173 * | |###########| | |
174 * | |###########| | Host |
175 * v |###########| | |
176 * total GM size ------> +-----------+ +-----------+
179 * zero on success, non-zero if configuration invalid or ballooning failed
181 int intel_vgt_balloon(struct drm_i915_private
*dev_priv
)
183 struct i915_ggtt
*ggtt
= &dev_priv
->ggtt
;
184 unsigned long ggtt_end
= ggtt
->base
.start
+ ggtt
->base
.total
;
186 unsigned long mappable_base
, mappable_size
, mappable_end
;
187 unsigned long unmappable_base
, unmappable_size
, unmappable_end
;
190 if (!intel_vgpu_active(dev_priv
))
193 mappable_base
= I915_READ(vgtif_reg(avail_rs
.mappable_gmadr
.base
));
194 mappable_size
= I915_READ(vgtif_reg(avail_rs
.mappable_gmadr
.size
));
195 unmappable_base
= I915_READ(vgtif_reg(avail_rs
.nonmappable_gmadr
.base
));
196 unmappable_size
= I915_READ(vgtif_reg(avail_rs
.nonmappable_gmadr
.size
));
198 mappable_end
= mappable_base
+ mappable_size
;
199 unmappable_end
= unmappable_base
+ unmappable_size
;
201 DRM_INFO("VGT ballooning configuration:\n");
202 DRM_INFO("Mappable graphic memory: base 0x%lx size %ldKiB\n",
203 mappable_base
, mappable_size
/ 1024);
204 DRM_INFO("Unmappable graphic memory: base 0x%lx size %ldKiB\n",
205 unmappable_base
, unmappable_size
/ 1024);
207 if (mappable_base
< ggtt
->base
.start
||
208 mappable_end
> ggtt
->mappable_end
||
209 unmappable_base
< ggtt
->mappable_end
||
210 unmappable_end
> ggtt_end
) {
211 DRM_ERROR("Invalid ballooning configuration!\n");
215 /* Unmappable graphic memory ballooning */
216 if (unmappable_base
> ggtt
->mappable_end
) {
217 ret
= vgt_balloon_space(&ggtt
->base
.mm
,
227 * No need to partition out the last physical page,
228 * because it is reserved to the guard page.
230 if (unmappable_end
< ggtt_end
- PAGE_SIZE
) {
231 ret
= vgt_balloon_space(&ggtt
->base
.mm
,
234 ggtt_end
- PAGE_SIZE
);
239 /* Mappable graphic memory ballooning */
240 if (mappable_base
> ggtt
->base
.start
) {
241 ret
= vgt_balloon_space(&ggtt
->base
.mm
,
243 ggtt
->base
.start
, mappable_base
);
249 if (mappable_end
< ggtt
->mappable_end
) {
250 ret
= vgt_balloon_space(&ggtt
->base
.mm
,
259 DRM_INFO("VGT balloon successfully\n");
263 DRM_ERROR("VGT balloon fail\n");
264 intel_vgt_deballoon(dev_priv
);
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