2 * Copyright(c) 2011-2015 Intel Corporation. All rights reserved.
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11 * The above copyright notice and this permission notice (including the next
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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,
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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)
63 struct intel_uncore *uncore = &dev_priv->uncore;
67 BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE);
69 magic = __raw_uncore_read64(uncore, vgtif_reg(magic));
70 if (magic != VGT_MAGIC)
73 version_major = __raw_uncore_read16(uncore, vgtif_reg(version_major));
74 if (version_major < VGT_VERSION_MAJOR) {
75 DRM_INFO("VGT interface version mismatch!\n");
79 dev_priv->vgpu.caps = __raw_uncore_read32(uncore, vgtif_reg(vgt_caps));
81 dev_priv->vgpu.active = true;
82 mutex_init(&dev_priv->vgpu.lock);
83 DRM_INFO("Virtual GPU for Intel GVT-g detected.\n");
86 bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *dev_priv)
88 return dev_priv->vgpu.caps & VGT_CAPS_FULL_PPGTT;
91 struct _balloon_info_ {
93 * There are up to 2 regions per mappable/unmappable graphic
94 * memory that might be ballooned. Here, index 0/1 is for mappable
95 * graphic memory, 2/3 for unmappable graphic memory.
97 struct drm_mm_node space[4];
100 static struct _balloon_info_ bl_info;
102 static void vgt_deballoon_space(struct i915_ggtt *ggtt,
103 struct drm_mm_node *node)
105 if (!drm_mm_node_allocated(node))
108 DRM_DEBUG_DRIVER("deballoon space: range [0x%llx - 0x%llx] %llu KiB.\n",
110 node->start + node->size,
113 ggtt->vm.reserved -= node->size;
114 drm_mm_remove_node(node);
118 * intel_vgt_deballoon - deballoon reserved graphics address trunks
119 * @dev_priv: i915 device private data
121 * This function is called to deallocate the ballooned-out graphic memory, when
122 * driver is unloaded or when ballooning fails.
124 void intel_vgt_deballoon(struct drm_i915_private *dev_priv)
128 if (!intel_vgpu_active(dev_priv))
131 DRM_DEBUG("VGT deballoon.\n");
133 for (i = 0; i < 4; i++)
134 vgt_deballoon_space(&dev_priv->ggtt, &bl_info.space[i]);
137 static int vgt_balloon_space(struct i915_ggtt *ggtt,
138 struct drm_mm_node *node,
139 unsigned long start, unsigned long end)
141 unsigned long size = end - start;
147 DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n",
148 start, end, size / 1024);
149 ret = i915_gem_gtt_reserve(&ggtt->vm, node,
150 size, start, I915_COLOR_UNEVICTABLE,
153 ggtt->vm.reserved += size;
159 * intel_vgt_balloon - balloon out reserved graphics address trunks
160 * @dev_priv: i915 device private data
162 * This function is called at the initialization stage, to balloon out the
163 * graphic address space allocated to other vGPUs, by marking these spaces as
164 * reserved. The ballooning related knowledge(starting address and size of
165 * the mappable/unmappable graphic memory) is described in the vgt_if structure
166 * in a reserved mmio range.
168 * To give an example, the drawing below depicts one typical scenario after
169 * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned
170 * out each for the mappable and the non-mappable part. From the vGPU1 point of
171 * view, the total size is the same as the physical one, with the start address
172 * of its graphic space being zero. Yet there are some portions ballooned out(
173 * the shadow part, which are marked as reserved by drm allocator). From the
174 * host point of view, the graphic address space is partitioned by multiple
175 * vGPUs in different VMs. ::
177 * vGPU1 view Host view
178 * 0 ------> +-----------+ +-----------+
179 * ^ |###########| | vGPU3 |
180 * | |###########| +-----------+
181 * | |###########| | vGPU2 |
182 * | +-----------+ +-----------+
183 * mappable GM | available | ==> | vGPU1 |
184 * | +-----------+ +-----------+
185 * | |###########| | |
186 * v |###########| | Host |
187 * +=======+===========+ +===========+
188 * ^ |###########| | vGPU3 |
189 * | |###########| +-----------+
190 * | |###########| | vGPU2 |
191 * | +-----------+ +-----------+
192 * unmappable GM | available | ==> | vGPU1 |
193 * | +-----------+ +-----------+
194 * | |###########| | |
195 * | |###########| | Host |
196 * v |###########| | |
197 * total GM size ------> +-----------+ +-----------+
200 * zero on success, non-zero if configuration invalid or ballooning failed
202 int intel_vgt_balloon(struct drm_i915_private *dev_priv)
204 struct i915_ggtt *ggtt = &dev_priv->ggtt;
205 unsigned long ggtt_end = ggtt->vm.total;
207 unsigned long mappable_base, mappable_size, mappable_end;
208 unsigned long unmappable_base, unmappable_size, unmappable_end;
211 if (!intel_vgpu_active(dev_priv))
214 mappable_base = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.base));
215 mappable_size = I915_READ(vgtif_reg(avail_rs.mappable_gmadr.size));
216 unmappable_base = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.base));
217 unmappable_size = I915_READ(vgtif_reg(avail_rs.nonmappable_gmadr.size));
219 mappable_end = mappable_base + mappable_size;
220 unmappable_end = unmappable_base + unmappable_size;
222 DRM_INFO("VGT ballooning configuration:\n");
223 DRM_INFO("Mappable graphic memory: base 0x%lx size %ldKiB\n",
224 mappable_base, mappable_size / 1024);
225 DRM_INFO("Unmappable graphic memory: base 0x%lx size %ldKiB\n",
226 unmappable_base, unmappable_size / 1024);
228 if (mappable_end > ggtt->mappable_end ||
229 unmappable_base < ggtt->mappable_end ||
230 unmappable_end > ggtt_end) {
231 DRM_ERROR("Invalid ballooning configuration!\n");
235 /* Unmappable graphic memory ballooning */
236 if (unmappable_base > ggtt->mappable_end) {
237 ret = vgt_balloon_space(ggtt, &bl_info.space[2],
238 ggtt->mappable_end, unmappable_base);
244 if (unmappable_end < ggtt_end) {
245 ret = vgt_balloon_space(ggtt, &bl_info.space[3],
246 unmappable_end, ggtt_end);
248 goto err_upon_mappable;
251 /* Mappable graphic memory ballooning */
253 ret = vgt_balloon_space(ggtt, &bl_info.space[0],
257 goto err_upon_unmappable;
260 if (mappable_end < ggtt->mappable_end) {
261 ret = vgt_balloon_space(ggtt, &bl_info.space[1],
262 mappable_end, ggtt->mappable_end);
265 goto err_below_mappable;
268 DRM_INFO("VGT balloon successfully\n");
272 vgt_deballoon_space(ggtt, &bl_info.space[0]);
274 vgt_deballoon_space(ggtt, &bl_info.space[3]);
276 vgt_deballoon_space(ggtt, &bl_info.space[2]);
278 DRM_ERROR("VGT balloon fail\n");