xref: /openbmc/linux/drivers/gpu/drm/i915/i915_vgpu.c (revision 7e00897b)
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 "i915_drv.h"
25 #include "i915_pvinfo.h"
26 #include "i915_vgpu.h"
27 
28 /**
29  * DOC: Intel GVT-g guest support
30  *
31  * Intel GVT-g is a graphics virtualization technology which shares the
32  * GPU among multiple virtual machines on a time-sharing basis. Each
33  * virtual machine is presented a virtual GPU (vGPU), which has equivalent
34  * features as the underlying physical GPU (pGPU), so i915 driver can run
35  * seamlessly in a virtual machine. This file provides vGPU specific
36  * optimizations when running in a virtual machine, to reduce the complexity
37  * of vGPU emulation and to improve the overall performance.
38  *
39  * A primary function introduced here is so-called "address space ballooning"
40  * technique. Intel GVT-g partitions global graphics memory among multiple VMs,
41  * so each VM can directly access a portion of the memory without hypervisor's
42  * intervention, e.g. filling textures or queuing commands. However with the
43  * partitioning an unmodified i915 driver would assume a smaller graphics
44  * memory starting from address ZERO, then requires vGPU emulation module to
45  * translate the graphics address between 'guest view' and 'host view', for
46  * all registers and command opcodes which contain a graphics memory address.
47  * To reduce the complexity, Intel GVT-g introduces "address space ballooning",
48  * by telling the exact partitioning knowledge to each guest i915 driver, which
49  * then reserves and prevents non-allocated portions from allocation. Thus vGPU
50  * emulation module only needs to scan and validate graphics addresses without
51  * complexity of address translation.
52  *
53  */
54 
55 /**
56  * intel_vgpu_detect - detect virtual GPU
57  * @dev_priv: i915 device private
58  *
59  * This function is called at the initialization stage, to detect whether
60  * running on a vGPU.
61  */
intel_vgpu_detect(struct drm_i915_private * dev_priv)62 void intel_vgpu_detect(struct drm_i915_private *dev_priv)
63 {
64 	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
65 	u64 magic;
66 	u16 version_major;
67 	void __iomem *shared_area;
68 
69 	BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE);
70 
71 	/*
72 	 * This is called before we setup the main MMIO BAR mappings used via
73 	 * the uncore structure, so we need to access the BAR directly. Since
74 	 * we do not support VGT on older gens, return early so we don't have
75 	 * to consider differently numbered or sized MMIO bars
76 	 */
77 	if (GRAPHICS_VER(dev_priv) < 6)
78 		return;
79 
80 	shared_area = pci_iomap_range(pdev, 0, VGT_PVINFO_PAGE, VGT_PVINFO_SIZE);
81 	if (!shared_area) {
82 		drm_err(&dev_priv->drm,
83 			"failed to map MMIO bar to check for VGT\n");
84 		return;
85 	}
86 
87 	magic = readq(shared_area + vgtif_offset(magic));
88 	if (magic != VGT_MAGIC)
89 		goto out;
90 
91 	version_major = readw(shared_area + vgtif_offset(version_major));
92 	if (version_major < VGT_VERSION_MAJOR) {
93 		drm_info(&dev_priv->drm, "VGT interface version mismatch!\n");
94 		goto out;
95 	}
96 
97 	dev_priv->vgpu.caps = readl(shared_area + vgtif_offset(vgt_caps));
98 
99 	dev_priv->vgpu.active = true;
100 	mutex_init(&dev_priv->vgpu.lock);
101 	drm_info(&dev_priv->drm, "Virtual GPU for Intel GVT-g detected.\n");
102 
103 out:
104 	pci_iounmap(pdev, shared_area);
105 }
106 
intel_vgpu_register(struct drm_i915_private * i915)107 void intel_vgpu_register(struct drm_i915_private *i915)
108 {
109 	/*
110 	 * Notify a valid surface after modesetting, when running inside a VM.
111 	 */
112 	if (intel_vgpu_active(i915))
113 		intel_uncore_write(&i915->uncore, vgtif_reg(display_ready),
114 				   VGT_DRV_DISPLAY_READY);
115 }
116 
intel_vgpu_active(struct drm_i915_private * dev_priv)117 bool intel_vgpu_active(struct drm_i915_private *dev_priv)
118 {
119 	return dev_priv->vgpu.active;
120 }
121 
intel_vgpu_has_full_ppgtt(struct drm_i915_private * dev_priv)122 bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *dev_priv)
123 {
124 	return dev_priv->vgpu.caps & VGT_CAPS_FULL_PPGTT;
125 }
126 
intel_vgpu_has_hwsp_emulation(struct drm_i915_private * dev_priv)127 bool intel_vgpu_has_hwsp_emulation(struct drm_i915_private *dev_priv)
128 {
129 	return dev_priv->vgpu.caps & VGT_CAPS_HWSP_EMULATION;
130 }
131 
intel_vgpu_has_huge_gtt(struct drm_i915_private * dev_priv)132 bool intel_vgpu_has_huge_gtt(struct drm_i915_private *dev_priv)
133 {
134 	return dev_priv->vgpu.caps & VGT_CAPS_HUGE_GTT;
135 }
136 
137 struct _balloon_info_ {
138 	/*
139 	 * There are up to 2 regions per mappable/unmappable graphic
140 	 * memory that might be ballooned. Here, index 0/1 is for mappable
141 	 * graphic memory, 2/3 for unmappable graphic memory.
142 	 */
143 	struct drm_mm_node space[4];
144 };
145 
146 static struct _balloon_info_ bl_info;
147 
vgt_deballoon_space(struct i915_ggtt * ggtt,struct drm_mm_node * node)148 static void vgt_deballoon_space(struct i915_ggtt *ggtt,
149 				struct drm_mm_node *node)
150 {
151 	struct drm_i915_private *dev_priv = ggtt->vm.i915;
152 	if (!drm_mm_node_allocated(node))
153 		return;
154 
155 	drm_dbg(&dev_priv->drm,
156 		"deballoon space: range [0x%llx - 0x%llx] %llu KiB.\n",
157 		node->start,
158 		node->start + node->size,
159 		node->size / 1024);
160 
161 	ggtt->vm.reserved -= node->size;
162 	drm_mm_remove_node(node);
163 }
164 
165 /**
166  * intel_vgt_deballoon - deballoon reserved graphics address trunks
167  * @ggtt: the global GGTT from which we reserved earlier
168  *
169  * This function is called to deallocate the ballooned-out graphic memory, when
170  * driver is unloaded or when ballooning fails.
171  */
intel_vgt_deballoon(struct i915_ggtt * ggtt)172 void intel_vgt_deballoon(struct i915_ggtt *ggtt)
173 {
174 	struct drm_i915_private *dev_priv = ggtt->vm.i915;
175 	int i;
176 
177 	if (!intel_vgpu_active(ggtt->vm.i915))
178 		return;
179 
180 	drm_dbg(&dev_priv->drm, "VGT deballoon.\n");
181 
182 	for (i = 0; i < 4; i++)
183 		vgt_deballoon_space(ggtt, &bl_info.space[i]);
184 }
185 
vgt_balloon_space(struct i915_ggtt * ggtt,struct drm_mm_node * node,unsigned long start,unsigned long end)186 static int vgt_balloon_space(struct i915_ggtt *ggtt,
187 			     struct drm_mm_node *node,
188 			     unsigned long start, unsigned long end)
189 {
190 	struct drm_i915_private *dev_priv = ggtt->vm.i915;
191 	unsigned long size = end - start;
192 	int ret;
193 
194 	if (start >= end)
195 		return -EINVAL;
196 
197 	drm_info(&dev_priv->drm,
198 		 "balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n",
199 		 start, end, size / 1024);
200 	ret = i915_gem_gtt_reserve(&ggtt->vm, NULL, node,
201 				   size, start, I915_COLOR_UNEVICTABLE,
202 				   0);
203 	if (!ret)
204 		ggtt->vm.reserved += size;
205 
206 	return ret;
207 }
208 
209 /**
210  * intel_vgt_balloon - balloon out reserved graphics address trunks
211  * @ggtt: the global GGTT from which to reserve
212  *
213  * This function is called at the initialization stage, to balloon out the
214  * graphic address space allocated to other vGPUs, by marking these spaces as
215  * reserved. The ballooning related knowledge(starting address and size of
216  * the mappable/unmappable graphic memory) is described in the vgt_if structure
217  * in a reserved mmio range.
218  *
219  * To give an example, the drawing below depicts one typical scenario after
220  * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned
221  * out each for the mappable and the non-mappable part. From the vGPU1 point of
222  * view, the total size is the same as the physical one, with the start address
223  * of its graphic space being zero. Yet there are some portions ballooned out(
224  * the shadow part, which are marked as reserved by drm allocator). From the
225  * host point of view, the graphic address space is partitioned by multiple
226  * vGPUs in different VMs. ::
227  *
228  *                         vGPU1 view         Host view
229  *              0 ------> +-----------+     +-----------+
230  *                ^       |###########|     |   vGPU3   |
231  *                |       |###########|     +-----------+
232  *                |       |###########|     |   vGPU2   |
233  *                |       +-----------+     +-----------+
234  *         mappable GM    | available | ==> |   vGPU1   |
235  *                |       +-----------+     +-----------+
236  *                |       |###########|     |           |
237  *                v       |###########|     |   Host    |
238  *                +=======+===========+     +===========+
239  *                ^       |###########|     |   vGPU3   |
240  *                |       |###########|     +-----------+
241  *                |       |###########|     |   vGPU2   |
242  *                |       +-----------+     +-----------+
243  *       unmappable GM    | available | ==> |   vGPU1   |
244  *                |       +-----------+     +-----------+
245  *                |       |###########|     |           |
246  *                |       |###########|     |   Host    |
247  *                v       |###########|     |           |
248  *  total GM size ------> +-----------+     +-----------+
249  *
250  * Returns:
251  * zero on success, non-zero if configuration invalid or ballooning failed
252  */
intel_vgt_balloon(struct i915_ggtt * ggtt)253 int intel_vgt_balloon(struct i915_ggtt *ggtt)
254 {
255 	struct drm_i915_private *dev_priv = ggtt->vm.i915;
256 	struct intel_uncore *uncore = &dev_priv->uncore;
257 	unsigned long ggtt_end = ggtt->vm.total;
258 
259 	unsigned long mappable_base, mappable_size, mappable_end;
260 	unsigned long unmappable_base, unmappable_size, unmappable_end;
261 	int ret;
262 
263 	if (!intel_vgpu_active(ggtt->vm.i915))
264 		return 0;
265 
266 	mappable_base =
267 	  intel_uncore_read(uncore, vgtif_reg(avail_rs.mappable_gmadr.base));
268 	mappable_size =
269 	  intel_uncore_read(uncore, vgtif_reg(avail_rs.mappable_gmadr.size));
270 	unmappable_base =
271 	  intel_uncore_read(uncore, vgtif_reg(avail_rs.nonmappable_gmadr.base));
272 	unmappable_size =
273 	  intel_uncore_read(uncore, vgtif_reg(avail_rs.nonmappable_gmadr.size));
274 
275 	mappable_end = mappable_base + mappable_size;
276 	unmappable_end = unmappable_base + unmappable_size;
277 
278 	drm_info(&dev_priv->drm, "VGT ballooning configuration:\n");
279 	drm_info(&dev_priv->drm,
280 		 "Mappable graphic memory: base 0x%lx size %ldKiB\n",
281 		 mappable_base, mappable_size / 1024);
282 	drm_info(&dev_priv->drm,
283 		 "Unmappable graphic memory: base 0x%lx size %ldKiB\n",
284 		 unmappable_base, unmappable_size / 1024);
285 
286 	if (mappable_end > ggtt->mappable_end ||
287 	    unmappable_base < ggtt->mappable_end ||
288 	    unmappable_end > ggtt_end) {
289 		drm_err(&dev_priv->drm, "Invalid ballooning configuration!\n");
290 		return -EINVAL;
291 	}
292 
293 	/* Unmappable graphic memory ballooning */
294 	if (unmappable_base > ggtt->mappable_end) {
295 		ret = vgt_balloon_space(ggtt, &bl_info.space[2],
296 					ggtt->mappable_end, unmappable_base);
297 
298 		if (ret)
299 			goto err;
300 	}
301 
302 	if (unmappable_end < ggtt_end) {
303 		ret = vgt_balloon_space(ggtt, &bl_info.space[3],
304 					unmappable_end, ggtt_end);
305 		if (ret)
306 			goto err_upon_mappable;
307 	}
308 
309 	/* Mappable graphic memory ballooning */
310 	if (mappable_base) {
311 		ret = vgt_balloon_space(ggtt, &bl_info.space[0],
312 					0, mappable_base);
313 
314 		if (ret)
315 			goto err_upon_unmappable;
316 	}
317 
318 	if (mappable_end < ggtt->mappable_end) {
319 		ret = vgt_balloon_space(ggtt, &bl_info.space[1],
320 					mappable_end, ggtt->mappable_end);
321 
322 		if (ret)
323 			goto err_below_mappable;
324 	}
325 
326 	drm_info(&dev_priv->drm, "VGT balloon successfully\n");
327 	return 0;
328 
329 err_below_mappable:
330 	vgt_deballoon_space(ggtt, &bl_info.space[0]);
331 err_upon_unmappable:
332 	vgt_deballoon_space(ggtt, &bl_info.space[3]);
333 err_upon_mappable:
334 	vgt_deballoon_space(ggtt, &bl_info.space[2]);
335 err:
336 	drm_err(&dev_priv->drm, "VGT balloon fail\n");
337 	return ret;
338 }
339