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1// SPDX-License-Identifier: GPL-2.0 OR MIT
2
3/*
4 * Xen para-virtual DRM device
5 *
6 * Copyright (C) 2016-2018 EPAM Systems Inc.
7 *
8 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
9 */
10
11#include <linux/dma-buf.h>
12#include <linux/scatterlist.h>
13#include <linux/shmem_fs.h>
14
15#include <drm/drm_fb_helper.h>
16#include <drm/drm_gem.h>
17#include <drm/drm_prime.h>
18#include <drm/drm_probe_helper.h>
19
20#include <xen/balloon.h>
21
22#include "xen_drm_front.h"
23#include "xen_drm_front_gem.h"
24
25struct xen_gem_object {
26 struct drm_gem_object base;
27
28 size_t num_pages;
29 struct page **pages;
30
31 /* set for buffers allocated by the backend */
32 bool be_alloc;
33
34 /* this is for imported PRIME buffer */
35 struct sg_table *sgt_imported;
36};
37
38static inline struct xen_gem_object *
39to_xen_gem_obj(struct drm_gem_object *gem_obj)
40{
41 return container_of(gem_obj, struct xen_gem_object, base);
42}
43
44static int gem_alloc_pages_array(struct xen_gem_object *xen_obj,
45 size_t buf_size)
46{
47 xen_obj->num_pages = DIV_ROUND_UP(buf_size, PAGE_SIZE);
48 xen_obj->pages = kvmalloc_array(xen_obj->num_pages,
49 sizeof(struct page *), GFP_KERNEL);
50 return !xen_obj->pages ? -ENOMEM : 0;
51}
52
53static void gem_free_pages_array(struct xen_gem_object *xen_obj)
54{
55 kvfree(xen_obj->pages);
56 xen_obj->pages = NULL;
57}
58
59static struct xen_gem_object *gem_create_obj(struct drm_device *dev,
60 size_t size)
61{
62 struct xen_gem_object *xen_obj;
63 int ret;
64
65 xen_obj = kzalloc(sizeof(*xen_obj), GFP_KERNEL);
66 if (!xen_obj)
67 return ERR_PTR(-ENOMEM);
68
69 ret = drm_gem_object_init(dev, &xen_obj->base, size);
70 if (ret < 0) {
71 kfree(xen_obj);
72 return ERR_PTR(ret);
73 }
74
75 return xen_obj;
76}
77
78static struct xen_gem_object *gem_create(struct drm_device *dev, size_t size)
79{
80 struct xen_drm_front_drm_info *drm_info = dev->dev_private;
81 struct xen_gem_object *xen_obj;
82 int ret;
83
84 size = round_up(size, PAGE_SIZE);
85 xen_obj = gem_create_obj(dev, size);
86 if (IS_ERR_OR_NULL(xen_obj))
87 return xen_obj;
88
89 if (drm_info->front_info->cfg.be_alloc) {
90 /*
91 * backend will allocate space for this buffer, so
92 * only allocate array of pointers to pages
93 */
94 ret = gem_alloc_pages_array(xen_obj, size);
95 if (ret < 0)
96 goto fail;
97
98 /*
99 * allocate ballooned pages which will be used to map
100 * grant references provided by the backend
101 */
102 ret = alloc_xenballooned_pages(xen_obj->num_pages,
103 xen_obj->pages);
104 if (ret < 0) {
105 DRM_ERROR("Cannot allocate %zu ballooned pages: %d\n",
106 xen_obj->num_pages, ret);
107 gem_free_pages_array(xen_obj);
108 goto fail;
109 }
110
111 xen_obj->be_alloc = true;
112 return xen_obj;
113 }
114 /*
115 * need to allocate backing pages now, so we can share those
116 * with the backend
117 */
118 xen_obj->num_pages = DIV_ROUND_UP(size, PAGE_SIZE);
119 xen_obj->pages = drm_gem_get_pages(&xen_obj->base);
120 if (IS_ERR_OR_NULL(xen_obj->pages)) {
121 ret = PTR_ERR(xen_obj->pages);
122 xen_obj->pages = NULL;
123 goto fail;
124 }
125
126 return xen_obj;
127
128fail:
129 DRM_ERROR("Failed to allocate buffer with size %zu\n", size);
130 return ERR_PTR(ret);
131}
132
133struct drm_gem_object *xen_drm_front_gem_create(struct drm_device *dev,
134 size_t size)
135{
136 struct xen_gem_object *xen_obj;
137
138 xen_obj = gem_create(dev, size);
139 if (IS_ERR_OR_NULL(xen_obj))
140 return ERR_CAST(xen_obj);
141
142 return &xen_obj->base;
143}
144
145void xen_drm_front_gem_free_object_unlocked(struct drm_gem_object *gem_obj)
146{
147 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
148
149 if (xen_obj->base.import_attach) {
150 drm_prime_gem_destroy(&xen_obj->base, xen_obj->sgt_imported);
151 gem_free_pages_array(xen_obj);
152 } else {
153 if (xen_obj->pages) {
154 if (xen_obj->be_alloc) {
155 free_xenballooned_pages(xen_obj->num_pages,
156 xen_obj->pages);
157 gem_free_pages_array(xen_obj);
158 } else {
159 drm_gem_put_pages(&xen_obj->base,
160 xen_obj->pages, true, false);
161 }
162 }
163 }
164 drm_gem_object_release(gem_obj);
165 kfree(xen_obj);
166}
167
168struct page **xen_drm_front_gem_get_pages(struct drm_gem_object *gem_obj)
169{
170 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
171
172 return xen_obj->pages;
173}
174
175struct sg_table *xen_drm_front_gem_get_sg_table(struct drm_gem_object *gem_obj)
176{
177 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
178
179 if (!xen_obj->pages)
180 return ERR_PTR(-ENOMEM);
181
182 return drm_prime_pages_to_sg(xen_obj->pages, xen_obj->num_pages);
183}
184
185struct drm_gem_object *
186xen_drm_front_gem_import_sg_table(struct drm_device *dev,
187 struct dma_buf_attachment *attach,
188 struct sg_table *sgt)
189{
190 struct xen_drm_front_drm_info *drm_info = dev->dev_private;
191 struct xen_gem_object *xen_obj;
192 size_t size;
193 int ret;
194
195 size = attach->dmabuf->size;
196 xen_obj = gem_create_obj(dev, size);
197 if (IS_ERR_OR_NULL(xen_obj))
198 return ERR_CAST(xen_obj);
199
200 ret = gem_alloc_pages_array(xen_obj, size);
201 if (ret < 0)
202 return ERR_PTR(ret);
203
204 xen_obj->sgt_imported = sgt;
205
206 ret = drm_prime_sg_to_page_addr_arrays(sgt, xen_obj->pages,
207 NULL, xen_obj->num_pages);
208 if (ret < 0)
209 return ERR_PTR(ret);
210
211 ret = xen_drm_front_dbuf_create(drm_info->front_info,
212 xen_drm_front_dbuf_to_cookie(&xen_obj->base),
213 0, 0, 0, size, xen_obj->pages);
214 if (ret < 0)
215 return ERR_PTR(ret);
216
217 DRM_DEBUG("Imported buffer of size %zu with nents %u\n",
218 size, sgt->nents);
219
220 return &xen_obj->base;
221}
222
223static int gem_mmap_obj(struct xen_gem_object *xen_obj,
224 struct vm_area_struct *vma)
225{
226 int ret;
227
228 /*
229 * clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
230 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
231 * the whole buffer.
232 */
233 vma->vm_flags &= ~VM_PFNMAP;
234 vma->vm_flags |= VM_MIXEDMAP;
235 vma->vm_pgoff = 0;
236 /*
237 * According to Xen on ARM ABI (xen/include/public/arch-arm.h):
238 * all memory which is shared with other entities in the system
239 * (including the hypervisor and other guests) must reside in memory
240 * which is mapped as Normal Inner Write-Back Outer Write-Back
241 * Inner-Shareable.
242 */
243 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
244
245 /*
246 * vm_operations_struct.fault handler will be called if CPU access
247 * to VM is here. For GPUs this isn't the case, because CPU
248 * doesn't touch the memory. Insert pages now, so both CPU and GPU are
249 * happy.
250 * FIXME: as we insert all the pages now then no .fault handler must
251 * be called, so don't provide one
252 */
253 ret = vm_map_pages(vma, xen_obj->pages, xen_obj->num_pages);
254 if (ret < 0)
255 DRM_ERROR("Failed to map pages into vma: %d\n", ret);
256
257 return ret;
258}
259
260int xen_drm_front_gem_mmap(struct file *filp, struct vm_area_struct *vma)
261{
262 struct xen_gem_object *xen_obj;
263 struct drm_gem_object *gem_obj;
264 int ret;
265
266 ret = drm_gem_mmap(filp, vma);
267 if (ret < 0)
268 return ret;
269
270 gem_obj = vma->vm_private_data;
271 xen_obj = to_xen_gem_obj(gem_obj);
272 return gem_mmap_obj(xen_obj, vma);
273}
274
275void *xen_drm_front_gem_prime_vmap(struct drm_gem_object *gem_obj)
276{
277 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
278
279 if (!xen_obj->pages)
280 return NULL;
281
282 /* Please see comment in gem_mmap_obj on mapping and attributes. */
283 return vmap(xen_obj->pages, xen_obj->num_pages,
284 VM_MAP, PAGE_KERNEL);
285}
286
287void xen_drm_front_gem_prime_vunmap(struct drm_gem_object *gem_obj,
288 void *vaddr)
289{
290 vunmap(vaddr);
291}
292
293int xen_drm_front_gem_prime_mmap(struct drm_gem_object *gem_obj,
294 struct vm_area_struct *vma)
295{
296 struct xen_gem_object *xen_obj;
297 int ret;
298
299 ret = drm_gem_mmap_obj(gem_obj, gem_obj->size, vma);
300 if (ret < 0)
301 return ret;
302
303 xen_obj = to_xen_gem_obj(gem_obj);
304 return gem_mmap_obj(xen_obj, vma);
305}
1// SPDX-License-Identifier: GPL-2.0 OR MIT
2
3/*
4 * Xen para-virtual DRM device
5 *
6 * Copyright (C) 2016-2018 EPAM Systems Inc.
7 *
8 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
9 */
10
11#include <linux/dma-buf.h>
12#include <linux/scatterlist.h>
13#include <linux/shmem_fs.h>
14
15#include <drm/drm_gem.h>
16#include <drm/drm_prime.h>
17#include <drm/drm_probe_helper.h>
18
19#include <xen/balloon.h>
20#include <xen/xen.h>
21
22#include "xen_drm_front.h"
23#include "xen_drm_front_gem.h"
24
25struct xen_gem_object {
26 struct drm_gem_object base;
27
28 size_t num_pages;
29 struct page **pages;
30
31 /* set for buffers allocated by the backend */
32 bool be_alloc;
33
34 /* this is for imported PRIME buffer */
35 struct sg_table *sgt_imported;
36};
37
38static inline struct xen_gem_object *
39to_xen_gem_obj(struct drm_gem_object *gem_obj)
40{
41 return container_of(gem_obj, struct xen_gem_object, base);
42}
43
44static int gem_alloc_pages_array(struct xen_gem_object *xen_obj,
45 size_t buf_size)
46{
47 xen_obj->num_pages = DIV_ROUND_UP(buf_size, PAGE_SIZE);
48 xen_obj->pages = kvmalloc_array(xen_obj->num_pages,
49 sizeof(struct page *), GFP_KERNEL);
50 return !xen_obj->pages ? -ENOMEM : 0;
51}
52
53static void gem_free_pages_array(struct xen_gem_object *xen_obj)
54{
55 kvfree(xen_obj->pages);
56 xen_obj->pages = NULL;
57}
58
59static int xen_drm_front_gem_object_mmap(struct drm_gem_object *gem_obj,
60 struct vm_area_struct *vma)
61{
62 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
63 int ret;
64
65 vma->vm_ops = gem_obj->funcs->vm_ops;
66
67 /*
68 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
69 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
70 * the whole buffer.
71 */
72 vma->vm_flags &= ~VM_PFNMAP;
73 vma->vm_flags |= VM_MIXEDMAP | VM_DONTEXPAND;
74 vma->vm_pgoff = 0;
75
76 /*
77 * According to Xen on ARM ABI (xen/include/public/arch-arm.h):
78 * all memory which is shared with other entities in the system
79 * (including the hypervisor and other guests) must reside in memory
80 * which is mapped as Normal Inner Write-Back Outer Write-Back
81 * Inner-Shareable.
82 */
83 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
84
85 /*
86 * vm_operations_struct.fault handler will be called if CPU access
87 * to VM is here. For GPUs this isn't the case, because CPU doesn't
88 * touch the memory. Insert pages now, so both CPU and GPU are happy.
89 *
90 * FIXME: as we insert all the pages now then no .fault handler must
91 * be called, so don't provide one
92 */
93 ret = vm_map_pages(vma, xen_obj->pages, xen_obj->num_pages);
94 if (ret < 0)
95 DRM_ERROR("Failed to map pages into vma: %d\n", ret);
96
97 return ret;
98}
99
100static const struct vm_operations_struct xen_drm_drv_vm_ops = {
101 .open = drm_gem_vm_open,
102 .close = drm_gem_vm_close,
103};
104
105static const struct drm_gem_object_funcs xen_drm_front_gem_object_funcs = {
106 .free = xen_drm_front_gem_object_free,
107 .get_sg_table = xen_drm_front_gem_get_sg_table,
108 .vmap = xen_drm_front_gem_prime_vmap,
109 .vunmap = xen_drm_front_gem_prime_vunmap,
110 .mmap = xen_drm_front_gem_object_mmap,
111 .vm_ops = &xen_drm_drv_vm_ops,
112};
113
114static struct xen_gem_object *gem_create_obj(struct drm_device *dev,
115 size_t size)
116{
117 struct xen_gem_object *xen_obj;
118 int ret;
119
120 xen_obj = kzalloc(sizeof(*xen_obj), GFP_KERNEL);
121 if (!xen_obj)
122 return ERR_PTR(-ENOMEM);
123
124 xen_obj->base.funcs = &xen_drm_front_gem_object_funcs;
125
126 ret = drm_gem_object_init(dev, &xen_obj->base, size);
127 if (ret < 0) {
128 kfree(xen_obj);
129 return ERR_PTR(ret);
130 }
131
132 return xen_obj;
133}
134
135static struct xen_gem_object *gem_create(struct drm_device *dev, size_t size)
136{
137 struct xen_drm_front_drm_info *drm_info = dev->dev_private;
138 struct xen_gem_object *xen_obj;
139 int ret;
140
141 size = round_up(size, PAGE_SIZE);
142 xen_obj = gem_create_obj(dev, size);
143 if (IS_ERR(xen_obj))
144 return xen_obj;
145
146 if (drm_info->front_info->cfg.be_alloc) {
147 /*
148 * backend will allocate space for this buffer, so
149 * only allocate array of pointers to pages
150 */
151 ret = gem_alloc_pages_array(xen_obj, size);
152 if (ret < 0)
153 goto fail;
154
155 /*
156 * allocate ballooned pages which will be used to map
157 * grant references provided by the backend
158 */
159 ret = xen_alloc_unpopulated_pages(xen_obj->num_pages,
160 xen_obj->pages);
161 if (ret < 0) {
162 DRM_ERROR("Cannot allocate %zu ballooned pages: %d\n",
163 xen_obj->num_pages, ret);
164 gem_free_pages_array(xen_obj);
165 goto fail;
166 }
167
168 xen_obj->be_alloc = true;
169 return xen_obj;
170 }
171 /*
172 * need to allocate backing pages now, so we can share those
173 * with the backend
174 */
175 xen_obj->num_pages = DIV_ROUND_UP(size, PAGE_SIZE);
176 xen_obj->pages = drm_gem_get_pages(&xen_obj->base);
177 if (IS_ERR(xen_obj->pages)) {
178 ret = PTR_ERR(xen_obj->pages);
179 xen_obj->pages = NULL;
180 goto fail;
181 }
182
183 return xen_obj;
184
185fail:
186 DRM_ERROR("Failed to allocate buffer with size %zu\n", size);
187 return ERR_PTR(ret);
188}
189
190struct drm_gem_object *xen_drm_front_gem_create(struct drm_device *dev,
191 size_t size)
192{
193 struct xen_gem_object *xen_obj;
194
195 xen_obj = gem_create(dev, size);
196 if (IS_ERR(xen_obj))
197 return ERR_CAST(xen_obj);
198
199 return &xen_obj->base;
200}
201
202void xen_drm_front_gem_free_object_unlocked(struct drm_gem_object *gem_obj)
203{
204 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
205
206 if (xen_obj->base.import_attach) {
207 drm_prime_gem_destroy(&xen_obj->base, xen_obj->sgt_imported);
208 gem_free_pages_array(xen_obj);
209 } else {
210 if (xen_obj->pages) {
211 if (xen_obj->be_alloc) {
212 xen_free_unpopulated_pages(xen_obj->num_pages,
213 xen_obj->pages);
214 gem_free_pages_array(xen_obj);
215 } else {
216 drm_gem_put_pages(&xen_obj->base,
217 xen_obj->pages, true, false);
218 }
219 }
220 }
221 drm_gem_object_release(gem_obj);
222 kfree(xen_obj);
223}
224
225struct page **xen_drm_front_gem_get_pages(struct drm_gem_object *gem_obj)
226{
227 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
228
229 return xen_obj->pages;
230}
231
232struct sg_table *xen_drm_front_gem_get_sg_table(struct drm_gem_object *gem_obj)
233{
234 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
235
236 if (!xen_obj->pages)
237 return ERR_PTR(-ENOMEM);
238
239 return drm_prime_pages_to_sg(gem_obj->dev,
240 xen_obj->pages, xen_obj->num_pages);
241}
242
243struct drm_gem_object *
244xen_drm_front_gem_import_sg_table(struct drm_device *dev,
245 struct dma_buf_attachment *attach,
246 struct sg_table *sgt)
247{
248 struct xen_drm_front_drm_info *drm_info = dev->dev_private;
249 struct xen_gem_object *xen_obj;
250 size_t size;
251 int ret;
252
253 size = attach->dmabuf->size;
254 xen_obj = gem_create_obj(dev, size);
255 if (IS_ERR(xen_obj))
256 return ERR_CAST(xen_obj);
257
258 ret = gem_alloc_pages_array(xen_obj, size);
259 if (ret < 0)
260 return ERR_PTR(ret);
261
262 xen_obj->sgt_imported = sgt;
263
264 ret = drm_prime_sg_to_page_array(sgt, xen_obj->pages,
265 xen_obj->num_pages);
266 if (ret < 0)
267 return ERR_PTR(ret);
268
269 ret = xen_drm_front_dbuf_create(drm_info->front_info,
270 xen_drm_front_dbuf_to_cookie(&xen_obj->base),
271 0, 0, 0, size, sgt->sgl->offset,
272 xen_obj->pages);
273 if (ret < 0)
274 return ERR_PTR(ret);
275
276 DRM_DEBUG("Imported buffer of size %zu with nents %u\n",
277 size, sgt->orig_nents);
278
279 return &xen_obj->base;
280}
281
282int xen_drm_front_gem_prime_vmap(struct drm_gem_object *gem_obj,
283 struct iosys_map *map)
284{
285 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
286 void *vaddr;
287
288 if (!xen_obj->pages)
289 return -ENOMEM;
290
291 /* Please see comment in gem_mmap_obj on mapping and attributes. */
292 vaddr = vmap(xen_obj->pages, xen_obj->num_pages,
293 VM_MAP, PAGE_KERNEL);
294 if (!vaddr)
295 return -ENOMEM;
296 iosys_map_set_vaddr(map, vaddr);
297
298 return 0;
299}
300
301void xen_drm_front_gem_prime_vunmap(struct drm_gem_object *gem_obj,
302 struct iosys_map *map)
303{
304 vunmap(map->vaddr);
305}