1 /* $NetBSD: i915_vgpu.c,v 1.6 2021/12/19 11:37:41 riastradh Exp $ */
2
3 /*
4 * Copyright(c) 2011-2015 Intel Corporation. All rights reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the next
14 * paragraph) shall be included in all copies or substantial portions of the
15 * Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 * SOFTWARE.
24 */
25
26 #include <sys/cdefs.h>
27 __KERNEL_RCSID(0, "$NetBSD: i915_vgpu.c,v 1.6 2021/12/19 11:37:41 riastradh Exp $");
28
29 #include "i915_vgpu.h"
30
31 #include <linux/nbsd-namespace.h>
32
33 /**
34 * DOC: Intel GVT-g guest support
35 *
36 * Intel GVT-g is a graphics virtualization technology which shares the
37 * GPU among multiple virtual machines on a time-sharing basis. Each
38 * virtual machine is presented a virtual GPU (vGPU), which has equivalent
39 * features as the underlying physical GPU (pGPU), so i915 driver can run
40 * seamlessly in a virtual machine. This file provides vGPU specific
41 * optimizations when running in a virtual machine, to reduce the complexity
42 * of vGPU emulation and to improve the overall performance.
43 *
44 * A primary function introduced here is so-called "address space ballooning"
45 * technique. Intel GVT-g partitions global graphics memory among multiple VMs,
46 * so each VM can directly access a portion of the memory without hypervisor's
47 * intervention, e.g. filling textures or queuing commands. However with the
48 * partitioning an unmodified i915 driver would assume a smaller graphics
49 * memory starting from address ZERO, then requires vGPU emulation module to
50 * translate the graphics address between 'guest view' and 'host view', for
51 * all registers and command opcodes which contain a graphics memory address.
52 * To reduce the complexity, Intel GVT-g introduces "address space ballooning",
53 * by telling the exact partitioning knowledge to each guest i915 driver, which
54 * then reserves and prevents non-allocated portions from allocation. Thus vGPU
55 * emulation module only needs to scan and validate graphics addresses without
56 * complexity of address translation.
57 *
58 */
59
60 /**
61 * i915_detect_vgpu - detect virtual GPU
62 * @dev_priv: i915 device private
63 *
64 * This function is called at the initialization stage, to detect whether
65 * running on a vGPU.
66 */
i915_detect_vgpu(struct drm_i915_private * dev_priv)67 void i915_detect_vgpu(struct drm_i915_private *dev_priv)
68 {
69 struct pci_dev *pdev = dev_priv->drm.pdev;
70 u64 magic;
71 u16 version_major;
72 #ifdef __NetBSD__
73 bus_space_tag_t bst;
74 bus_space_handle_t bsh;
75 bus_size_t off = VGT_PVINFO_PAGE;
76 bus_size_t size = VGT_PVINFO_SIZE;
77 #else
78 void __iomem *shared_area;
79 #endif
80
81 BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE);
82
83 /*
84 * This is called before we setup the main MMIO BAR mappings used via
85 * the uncore structure, so we need to access the BAR directly. Since
86 * we do not support VGT on older gens, return early so we don't have
87 * to consider differently numbered or sized MMIO bars
88 */
89 if (INTEL_GEN(dev_priv) < 6)
90 return;
91
92 #ifdef __NetBSD__
93 bst = pdev->pd_pa.pa_memt;
94 if (off > pdev->pd_resources[0].size ||
95 size > pdev->pd_resources[0].size - off ||
96 bus_space_map(bst, pdev->pd_resources[0].addr + off, size,
97 pdev->pd_resources[0].flags, &bsh)) {
98 DRM_ERROR("failed to map MMIO bar to check for VGT\n");
99 return;
100 }
101 # ifdef _LP64
102 magic = bus_space_read_8(bst, bsh, (bus_size_t)vgtif_offset(magic));
103 # else
104 magic = bus_space_read_4(bst, bsh, (bus_size_t)vgtif_offset(magic));
105 magic |= (uint64_t)bus_space_read_4(bst, bsh,
106 (bus_size_t)vgtif_offset(magic) + 4)
107 << 32;
108 # endif
109 #else
110 shared_area = pci_iomap_range(pdev, 0, VGT_PVINFO_PAGE, VGT_PVINFO_SIZE);
111 if (!shared_area) {
112 DRM_ERROR("failed to map MMIO bar to check for VGT\n");
113 return;
114 }
115 magic = readq(shared_area + vgtif_offset(magic));
116 #endif
117
118 if (magic != VGT_MAGIC)
119 goto out;
120
121 #ifdef __NetBSD__
122 version_major = bus_space_read_2(bst, bsh,
123 (bus_size_t)vgtif_offset(version_major));
124 #else
125 version_major = readw(shared_area + vgtif_offset(version_major));
126 #endif
127 if (version_major < VGT_VERSION_MAJOR) {
128 DRM_INFO("VGT interface version mismatch!\n");
129 goto out;
130 }
131
132 #ifdef __NetBSD__
133 dev_priv->vgpu.caps = bus_space_read_4(bst, bsh,
134 (bus_size_t)vgtif_offset(vgt_caps));
135 #else
136 dev_priv->vgpu.caps = readl(shared_area + vgtif_offset(vgt_caps));
137 #endif
138
139 dev_priv->vgpu.active = true;
140 mutex_init(&dev_priv->vgpu.lock);
141 DRM_INFO("Virtual GPU for Intel GVT-g detected.\n");
142
143 out:
144 #ifdef __NetBSD__
145 bus_space_unmap(bst, bsh, size);
146 #else
147 pci_iounmap(pdev, shared_area);
148 #endif
149 }
150
intel_vgpu_has_full_ppgtt(struct drm_i915_private * dev_priv)151 bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *dev_priv)
152 {
153 return dev_priv->vgpu.caps & VGT_CAPS_FULL_PPGTT;
154 }
155
156 struct _balloon_info_ {
157 /*
158 * There are up to 2 regions per mappable/unmappable graphic
159 * memory that might be ballooned. Here, index 0/1 is for mappable
160 * graphic memory, 2/3 for unmappable graphic memory.
161 */
162 struct drm_mm_node space[4];
163 };
164
165 static struct _balloon_info_ bl_info;
166
vgt_deballoon_space(struct i915_ggtt * ggtt,struct drm_mm_node * node)167 static void vgt_deballoon_space(struct i915_ggtt *ggtt,
168 struct drm_mm_node *node)
169 {
170 if (!drm_mm_node_allocated(node))
171 return;
172
173 DRM_DEBUG_DRIVER("deballoon space: range [0x%"PRIx64" - 0x%"PRIx64"] %"PRIu64" KiB.\n",
174 node->start,
175 node->start + node->size,
176 node->size / 1024);
177
178 ggtt->vm.reserved -= node->size;
179 drm_mm_remove_node(node);
180 }
181
182 /**
183 * intel_vgt_deballoon - deballoon reserved graphics address trunks
184 * @ggtt: the global GGTT from which we reserved earlier
185 *
186 * This function is called to deallocate the ballooned-out graphic memory, when
187 * driver is unloaded or when ballooning fails.
188 */
intel_vgt_deballoon(struct i915_ggtt * ggtt)189 void intel_vgt_deballoon(struct i915_ggtt *ggtt)
190 {
191 int i;
192
193 if (!intel_vgpu_active(ggtt->vm.i915))
194 return;
195
196 DRM_DEBUG("VGT deballoon.\n");
197
198 for (i = 0; i < 4; i++)
199 vgt_deballoon_space(ggtt, &bl_info.space[i]);
200 }
201
vgt_balloon_space(struct i915_ggtt * ggtt,struct drm_mm_node * node,unsigned long start,unsigned long end)202 static int vgt_balloon_space(struct i915_ggtt *ggtt,
203 struct drm_mm_node *node,
204 unsigned long start, unsigned long end)
205 {
206 unsigned long size = end - start;
207 int ret;
208
209 if (start >= end)
210 return -EINVAL;
211
212 DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n",
213 start, end, size / 1024);
214 ret = i915_gem_gtt_reserve(&ggtt->vm, node,
215 size, start, I915_COLOR_UNEVICTABLE,
216 0);
217 if (!ret)
218 ggtt->vm.reserved += size;
219
220 return ret;
221 }
222
223 /**
224 * intel_vgt_balloon - balloon out reserved graphics address trunks
225 * @ggtt: the global GGTT from which to reserve
226 *
227 * This function is called at the initialization stage, to balloon out the
228 * graphic address space allocated to other vGPUs, by marking these spaces as
229 * reserved. The ballooning related knowledge(starting address and size of
230 * the mappable/unmappable graphic memory) is described in the vgt_if structure
231 * in a reserved mmio range.
232 *
233 * To give an example, the drawing below depicts one typical scenario after
234 * ballooning. Here the vGPU1 has 2 pieces of graphic address spaces ballooned
235 * out each for the mappable and the non-mappable part. From the vGPU1 point of
236 * view, the total size is the same as the physical one, with the start address
237 * of its graphic space being zero. Yet there are some portions ballooned out(
238 * the shadow part, which are marked as reserved by drm allocator). From the
239 * host point of view, the graphic address space is partitioned by multiple
240 * vGPUs in different VMs. ::
241 *
242 * vGPU1 view Host view
243 * 0 ------> +-----------+ +-----------+
244 * ^ |###########| | vGPU3 |
245 * | |###########| +-----------+
246 * | |###########| | vGPU2 |
247 * | +-----------+ +-----------+
248 * mappable GM | available | ==> | vGPU1 |
249 * | +-----------+ +-----------+
250 * | |###########| | |
251 * v |###########| | Host |
252 * +=======+===========+ +===========+
253 * ^ |###########| | vGPU3 |
254 * | |###########| +-----------+
255 * | |###########| | vGPU2 |
256 * | +-----------+ +-----------+
257 * unmappable GM | available | ==> | vGPU1 |
258 * | +-----------+ +-----------+
259 * | |###########| | |
260 * | |###########| | Host |
261 * v |###########| | |
262 * total GM size ------> +-----------+ +-----------+
263 *
264 * Returns:
265 * zero on success, non-zero if configuration invalid or ballooning failed
266 */
intel_vgt_balloon(struct i915_ggtt * ggtt)267 int intel_vgt_balloon(struct i915_ggtt *ggtt)
268 {
269 struct intel_uncore *uncore = &ggtt->vm.i915->uncore;
270 unsigned long ggtt_end = ggtt->vm.total;
271
272 unsigned long mappable_base, mappable_size, mappable_end;
273 unsigned long unmappable_base, unmappable_size, unmappable_end;
274 int ret;
275
276 if (!intel_vgpu_active(ggtt->vm.i915))
277 return 0;
278
279 mappable_base =
280 intel_uncore_read(uncore, vgtif_reg(avail_rs.mappable_gmadr.base));
281 mappable_size =
282 intel_uncore_read(uncore, vgtif_reg(avail_rs.mappable_gmadr.size));
283 unmappable_base =
284 intel_uncore_read(uncore, vgtif_reg(avail_rs.nonmappable_gmadr.base));
285 unmappable_size =
286 intel_uncore_read(uncore, vgtif_reg(avail_rs.nonmappable_gmadr.size));
287
288 mappable_end = mappable_base + mappable_size;
289 unmappable_end = unmappable_base + unmappable_size;
290
291 DRM_INFO("VGT ballooning configuration:\n");
292 DRM_INFO("Mappable graphic memory: base 0x%lx size %ldKiB\n",
293 mappable_base, mappable_size / 1024);
294 DRM_INFO("Unmappable graphic memory: base 0x%lx size %ldKiB\n",
295 unmappable_base, unmappable_size / 1024);
296
297 if (mappable_end > ggtt->mappable_end ||
298 unmappable_base < ggtt->mappable_end ||
299 unmappable_end > ggtt_end) {
300 DRM_ERROR("Invalid ballooning configuration!\n");
301 return -EINVAL;
302 }
303
304 /* Unmappable graphic memory ballooning */
305 if (unmappable_base > ggtt->mappable_end) {
306 ret = vgt_balloon_space(ggtt, &bl_info.space[2],
307 ggtt->mappable_end, unmappable_base);
308
309 if (ret)
310 goto err;
311 }
312
313 if (unmappable_end < ggtt_end) {
314 ret = vgt_balloon_space(ggtt, &bl_info.space[3],
315 unmappable_end, ggtt_end);
316 if (ret)
317 goto err_upon_mappable;
318 }
319
320 /* Mappable graphic memory ballooning */
321 if (mappable_base) {
322 ret = vgt_balloon_space(ggtt, &bl_info.space[0],
323 0, mappable_base);
324
325 if (ret)
326 goto err_upon_unmappable;
327 }
328
329 if (mappable_end < ggtt->mappable_end) {
330 ret = vgt_balloon_space(ggtt, &bl_info.space[1],
331 mappable_end, ggtt->mappable_end);
332
333 if (ret)
334 goto err_below_mappable;
335 }
336
337 DRM_INFO("VGT balloon successfully\n");
338 return 0;
339
340 err_below_mappable:
341 vgt_deballoon_space(ggtt, &bl_info.space[0]);
342 err_upon_unmappable:
343 vgt_deballoon_space(ggtt, &bl_info.space[3]);
344 err_upon_mappable:
345 vgt_deballoon_space(ggtt, &bl_info.space[2]);
346 err:
347 DRM_ERROR("VGT balloon fail\n");
348 return ret;
349 }
350