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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_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#include <xen/xen.h>
22
23#include "xen_drm_front.h"
24#include "xen_drm_front_gem.h"
25
26struct xen_gem_object {
27 struct drm_gem_object base;
28
29 size_t num_pages;
30 struct page **pages;
31
32 /* set for buffers allocated by the backend */
33 bool be_alloc;
34
35 /* this is for imported PRIME buffer */
36 struct sg_table *sgt_imported;
37};
38
39static inline struct xen_gem_object *
40to_xen_gem_obj(struct drm_gem_object *gem_obj)
41{
42 return container_of(gem_obj, struct xen_gem_object, base);
43}
44
45static int gem_alloc_pages_array(struct xen_gem_object *xen_obj,
46 size_t buf_size)
47{
48 xen_obj->num_pages = DIV_ROUND_UP(buf_size, PAGE_SIZE);
49 xen_obj->pages = kvmalloc_array(xen_obj->num_pages,
50 sizeof(struct page *), GFP_KERNEL);
51 return !xen_obj->pages ? -ENOMEM : 0;
52}
53
54static void gem_free_pages_array(struct xen_gem_object *xen_obj)
55{
56 kvfree(xen_obj->pages);
57 xen_obj->pages = NULL;
58}
59
60static struct xen_gem_object *gem_create_obj(struct drm_device *dev,
61 size_t size)
62{
63 struct xen_gem_object *xen_obj;
64 int ret;
65
66 xen_obj = kzalloc(sizeof(*xen_obj), GFP_KERNEL);
67 if (!xen_obj)
68 return ERR_PTR(-ENOMEM);
69
70 ret = drm_gem_object_init(dev, &xen_obj->base, size);
71 if (ret < 0) {
72 kfree(xen_obj);
73 return ERR_PTR(ret);
74 }
75
76 return xen_obj;
77}
78
79static struct xen_gem_object *gem_create(struct drm_device *dev, size_t size)
80{
81 struct xen_drm_front_drm_info *drm_info = dev->dev_private;
82 struct xen_gem_object *xen_obj;
83 int ret;
84
85 size = round_up(size, PAGE_SIZE);
86 xen_obj = gem_create_obj(dev, size);
87 if (IS_ERR(xen_obj))
88 return xen_obj;
89
90 if (drm_info->front_info->cfg.be_alloc) {
91 /*
92 * backend will allocate space for this buffer, so
93 * only allocate array of pointers to pages
94 */
95 ret = gem_alloc_pages_array(xen_obj, size);
96 if (ret < 0)
97 goto fail;
98
99 /*
100 * allocate ballooned pages which will be used to map
101 * grant references provided by the backend
102 */
103 ret = xen_alloc_unpopulated_pages(xen_obj->num_pages,
104 xen_obj->pages);
105 if (ret < 0) {
106 DRM_ERROR("Cannot allocate %zu ballooned pages: %d\n",
107 xen_obj->num_pages, ret);
108 gem_free_pages_array(xen_obj);
109 goto fail;
110 }
111
112 xen_obj->be_alloc = true;
113 return xen_obj;
114 }
115 /*
116 * need to allocate backing pages now, so we can share those
117 * with the backend
118 */
119 xen_obj->num_pages = DIV_ROUND_UP(size, PAGE_SIZE);
120 xen_obj->pages = drm_gem_get_pages(&xen_obj->base);
121 if (IS_ERR(xen_obj->pages)) {
122 ret = PTR_ERR(xen_obj->pages);
123 xen_obj->pages = NULL;
124 goto fail;
125 }
126
127 return xen_obj;
128
129fail:
130 DRM_ERROR("Failed to allocate buffer with size %zu\n", size);
131 return ERR_PTR(ret);
132}
133
134struct drm_gem_object *xen_drm_front_gem_create(struct drm_device *dev,
135 size_t size)
136{
137 struct xen_gem_object *xen_obj;
138
139 xen_obj = gem_create(dev, size);
140 if (IS_ERR(xen_obj))
141 return ERR_CAST(xen_obj);
142
143 return &xen_obj->base;
144}
145
146void xen_drm_front_gem_free_object_unlocked(struct drm_gem_object *gem_obj)
147{
148 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
149
150 if (xen_obj->base.import_attach) {
151 drm_prime_gem_destroy(&xen_obj->base, xen_obj->sgt_imported);
152 gem_free_pages_array(xen_obj);
153 } else {
154 if (xen_obj->pages) {
155 if (xen_obj->be_alloc) {
156 xen_free_unpopulated_pages(xen_obj->num_pages,
157 xen_obj->pages);
158 gem_free_pages_array(xen_obj);
159 } else {
160 drm_gem_put_pages(&xen_obj->base,
161 xen_obj->pages, true, false);
162 }
163 }
164 }
165 drm_gem_object_release(gem_obj);
166 kfree(xen_obj);
167}
168
169struct page **xen_drm_front_gem_get_pages(struct drm_gem_object *gem_obj)
170{
171 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
172
173 return xen_obj->pages;
174}
175
176struct sg_table *xen_drm_front_gem_get_sg_table(struct drm_gem_object *gem_obj)
177{
178 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
179
180 if (!xen_obj->pages)
181 return ERR_PTR(-ENOMEM);
182
183 return drm_prime_pages_to_sg(xen_obj->pages, xen_obj->num_pages);
184}
185
186struct drm_gem_object *
187xen_drm_front_gem_import_sg_table(struct drm_device *dev,
188 struct dma_buf_attachment *attach,
189 struct sg_table *sgt)
190{
191 struct xen_drm_front_drm_info *drm_info = dev->dev_private;
192 struct xen_gem_object *xen_obj;
193 size_t size;
194 int ret;
195
196 size = attach->dmabuf->size;
197 xen_obj = gem_create_obj(dev, size);
198 if (IS_ERR(xen_obj))
199 return ERR_CAST(xen_obj);
200
201 ret = gem_alloc_pages_array(xen_obj, size);
202 if (ret < 0)
203 return ERR_PTR(ret);
204
205 xen_obj->sgt_imported = sgt;
206
207 ret = drm_prime_sg_to_page_addr_arrays(sgt, xen_obj->pages,
208 NULL, xen_obj->num_pages);
209 if (ret < 0)
210 return ERR_PTR(ret);
211
212 ret = xen_drm_front_dbuf_create(drm_info->front_info,
213 xen_drm_front_dbuf_to_cookie(&xen_obj->base),
214 0, 0, 0, size, sgt->sgl->offset,
215 xen_obj->pages);
216 if (ret < 0)
217 return ERR_PTR(ret);
218
219 DRM_DEBUG("Imported buffer of size %zu with nents %u\n",
220 size, sgt->nents);
221
222 return &xen_obj->base;
223}
224
225static int gem_mmap_obj(struct xen_gem_object *xen_obj,
226 struct vm_area_struct *vma)
227{
228 int ret;
229
230 /*
231 * clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
232 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
233 * the whole buffer.
234 */
235 vma->vm_flags &= ~VM_PFNMAP;
236 vma->vm_flags |= VM_MIXEDMAP;
237 vma->vm_pgoff = 0;
238 /*
239 * According to Xen on ARM ABI (xen/include/public/arch-arm.h):
240 * all memory which is shared with other entities in the system
241 * (including the hypervisor and other guests) must reside in memory
242 * which is mapped as Normal Inner Write-Back Outer Write-Back
243 * Inner-Shareable.
244 */
245 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
246
247 /*
248 * vm_operations_struct.fault handler will be called if CPU access
249 * to VM is here. For GPUs this isn't the case, because CPU
250 * doesn't touch the memory. Insert pages now, so both CPU and GPU are
251 * happy.
252 * FIXME: as we insert all the pages now then no .fault handler must
253 * be called, so don't provide one
254 */
255 ret = vm_map_pages(vma, xen_obj->pages, xen_obj->num_pages);
256 if (ret < 0)
257 DRM_ERROR("Failed to map pages into vma: %d\n", ret);
258
259 return ret;
260}
261
262int xen_drm_front_gem_mmap(struct file *filp, struct vm_area_struct *vma)
263{
264 struct xen_gem_object *xen_obj;
265 struct drm_gem_object *gem_obj;
266 int ret;
267
268 ret = drm_gem_mmap(filp, vma);
269 if (ret < 0)
270 return ret;
271
272 gem_obj = vma->vm_private_data;
273 xen_obj = to_xen_gem_obj(gem_obj);
274 return gem_mmap_obj(xen_obj, vma);
275}
276
277void *xen_drm_front_gem_prime_vmap(struct drm_gem_object *gem_obj)
278{
279 struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
280
281 if (!xen_obj->pages)
282 return NULL;
283
284 /* Please see comment in gem_mmap_obj on mapping and attributes. */
285 return vmap(xen_obj->pages, xen_obj->num_pages,
286 VM_MAP, PAGE_KERNEL);
287}
288
289void xen_drm_front_gem_prime_vunmap(struct drm_gem_object *gem_obj,
290 void *vaddr)
291{
292 vunmap(vaddr);
293}
294
295int xen_drm_front_gem_prime_mmap(struct drm_gem_object *gem_obj,
296 struct vm_area_struct *vma)
297{
298 struct xen_gem_object *xen_obj;
299 int ret;
300
301 ret = drm_gem_mmap_obj(gem_obj, gem_obj->size, vma);
302 if (ret < 0)
303 return ret;
304
305 xen_obj = to_xen_gem_obj(gem_obj);
306 return gem_mmap_obj(xen_obj, vma);
307}