1 // SPDX-License-Identifier: MIT
2 /* Copyright (C) 2006-2017 Oracle Corporation */
3
4 #include <linux/vbox_err.h>
5 #include "vbox_drv.h"
6 #include "vboxvideo_guest.h"
7 #include "hgsmi_channels.h"
8
9 /*
10 * There is a hardware ring buffer in the graphics device video RAM, formerly
11 * in the VBox VMMDev PCI memory space.
12 * All graphics commands go there serialized by vbva_buffer_begin_update.
13 * and vbva_buffer_end_update.
14 *
15 * free_offset is writing position. data_offset is reading position.
16 * free_offset == data_offset means buffer is empty.
17 * There must be always gap between data_offset and free_offset when data
18 * are in the buffer.
19 * Guest only changes free_offset, host changes data_offset.
20 */
21
vbva_buffer_available(const struct vbva_buffer * vbva)22 static u32 vbva_buffer_available(const struct vbva_buffer *vbva)
23 {
24 s32 diff = vbva->data_offset - vbva->free_offset;
25
26 return diff > 0 ? diff : vbva->data_len + diff;
27 }
28
vbva_buffer_place_data_at(struct vbva_buf_ctx * vbva_ctx,const void * p,u32 len,u32 offset)29 static void vbva_buffer_place_data_at(struct vbva_buf_ctx *vbva_ctx,
30 const void *p, u32 len, u32 offset)
31 {
32 struct vbva_buffer *vbva = vbva_ctx->vbva;
33 u32 bytes_till_boundary = vbva->data_len - offset;
34 u8 *dst = &vbva->data[offset];
35 s32 diff = len - bytes_till_boundary;
36
37 if (diff <= 0) {
38 /* Chunk will not cross buffer boundary. */
39 memcpy(dst, p, len);
40 } else {
41 /* Chunk crosses buffer boundary. */
42 memcpy(dst, p, bytes_till_boundary);
43 memcpy(&vbva->data[0], (u8 *)p + bytes_till_boundary, diff);
44 }
45 }
46
vbva_buffer_flush(struct gen_pool * ctx)47 static void vbva_buffer_flush(struct gen_pool *ctx)
48 {
49 struct vbva_flush *p;
50
51 p = hgsmi_buffer_alloc(ctx, sizeof(*p), HGSMI_CH_VBVA, VBVA_FLUSH);
52 if (!p)
53 return;
54
55 p->reserved = 0;
56
57 hgsmi_buffer_submit(ctx, p);
58 hgsmi_buffer_free(ctx, p);
59 }
60
vbva_write(struct vbva_buf_ctx * vbva_ctx,struct gen_pool * ctx,const void * p,u32 len)61 bool vbva_write(struct vbva_buf_ctx *vbva_ctx, struct gen_pool *ctx,
62 const void *p, u32 len)
63 {
64 struct vbva_record *record;
65 struct vbva_buffer *vbva;
66 u32 available;
67
68 vbva = vbva_ctx->vbva;
69 record = vbva_ctx->record;
70
71 if (!vbva || vbva_ctx->buffer_overflow ||
72 !record || !(record->len_and_flags & VBVA_F_RECORD_PARTIAL))
73 return false;
74
75 available = vbva_buffer_available(vbva);
76
77 while (len > 0) {
78 u32 chunk = len;
79
80 if (chunk >= available) {
81 vbva_buffer_flush(ctx);
82 available = vbva_buffer_available(vbva);
83 }
84
85 if (chunk >= available) {
86 if (WARN_ON(available <= vbva->partial_write_tresh)) {
87 vbva_ctx->buffer_overflow = true;
88 return false;
89 }
90 chunk = available - vbva->partial_write_tresh;
91 }
92
93 vbva_buffer_place_data_at(vbva_ctx, p, chunk,
94 vbva->free_offset);
95
96 vbva->free_offset = (vbva->free_offset + chunk) %
97 vbva->data_len;
98 record->len_and_flags += chunk;
99 available -= chunk;
100 len -= chunk;
101 p += chunk;
102 }
103
104 return true;
105 }
106
vbva_inform_host(struct vbva_buf_ctx * vbva_ctx,struct gen_pool * ctx,s32 screen,bool enable)107 static bool vbva_inform_host(struct vbva_buf_ctx *vbva_ctx,
108 struct gen_pool *ctx, s32 screen, bool enable)
109 {
110 struct vbva_enable_ex *p;
111 bool ret;
112
113 p = hgsmi_buffer_alloc(ctx, sizeof(*p), HGSMI_CH_VBVA, VBVA_ENABLE);
114 if (!p)
115 return false;
116
117 p->base.flags = enable ? VBVA_F_ENABLE : VBVA_F_DISABLE;
118 p->base.offset = vbva_ctx->buffer_offset;
119 p->base.result = VERR_NOT_SUPPORTED;
120 if (screen >= 0) {
121 p->base.flags |= VBVA_F_EXTENDED | VBVA_F_ABSOFFSET;
122 p->screen_id = screen;
123 }
124
125 hgsmi_buffer_submit(ctx, p);
126
127 if (enable)
128 ret = p->base.result >= 0;
129 else
130 ret = true;
131
132 hgsmi_buffer_free(ctx, p);
133
134 return ret;
135 }
136
vbva_enable(struct vbva_buf_ctx * vbva_ctx,struct gen_pool * ctx,struct vbva_buffer * vbva,s32 screen)137 bool vbva_enable(struct vbva_buf_ctx *vbva_ctx, struct gen_pool *ctx,
138 struct vbva_buffer *vbva, s32 screen)
139 {
140 bool ret = false;
141
142 memset(vbva, 0, sizeof(*vbva));
143 vbva->partial_write_tresh = 256;
144 vbva->data_len = vbva_ctx->buffer_length - sizeof(struct vbva_buffer);
145 vbva_ctx->vbva = vbva;
146
147 ret = vbva_inform_host(vbva_ctx, ctx, screen, true);
148 if (!ret)
149 vbva_disable(vbva_ctx, ctx, screen);
150
151 return ret;
152 }
153
vbva_disable(struct vbva_buf_ctx * vbva_ctx,struct gen_pool * ctx,s32 screen)154 void vbva_disable(struct vbva_buf_ctx *vbva_ctx, struct gen_pool *ctx,
155 s32 screen)
156 {
157 vbva_ctx->buffer_overflow = false;
158 vbva_ctx->record = NULL;
159 vbva_ctx->vbva = NULL;
160
161 vbva_inform_host(vbva_ctx, ctx, screen, false);
162 }
163
vbva_buffer_begin_update(struct vbva_buf_ctx * vbva_ctx,struct gen_pool * ctx)164 bool vbva_buffer_begin_update(struct vbva_buf_ctx *vbva_ctx,
165 struct gen_pool *ctx)
166 {
167 struct vbva_record *record;
168 u32 next;
169
170 if (!vbva_ctx->vbva ||
171 !(vbva_ctx->vbva->host_flags.host_events & VBVA_F_MODE_ENABLED))
172 return false;
173
174 WARN_ON(vbva_ctx->buffer_overflow || vbva_ctx->record);
175
176 next = (vbva_ctx->vbva->record_free_index + 1) % VBVA_MAX_RECORDS;
177
178 /* Flush if all slots in the records queue are used */
179 if (next == vbva_ctx->vbva->record_first_index)
180 vbva_buffer_flush(ctx);
181
182 /* If even after flush there is no place then fail the request */
183 if (next == vbva_ctx->vbva->record_first_index)
184 return false;
185
186 record = &vbva_ctx->vbva->records[vbva_ctx->vbva->record_free_index];
187 record->len_and_flags = VBVA_F_RECORD_PARTIAL;
188 vbva_ctx->vbva->record_free_index = next;
189 /* Remember which record we are using. */
190 vbva_ctx->record = record;
191
192 return true;
193 }
194
vbva_buffer_end_update(struct vbva_buf_ctx * vbva_ctx)195 void vbva_buffer_end_update(struct vbva_buf_ctx *vbva_ctx)
196 {
197 struct vbva_record *record = vbva_ctx->record;
198
199 WARN_ON(!vbva_ctx->vbva || !record ||
200 !(record->len_and_flags & VBVA_F_RECORD_PARTIAL));
201
202 /* Mark the record completed. */
203 record->len_and_flags &= ~VBVA_F_RECORD_PARTIAL;
204
205 vbva_ctx->buffer_overflow = false;
206 vbva_ctx->record = NULL;
207 }
208
vbva_setup_buffer_context(struct vbva_buf_ctx * vbva_ctx,u32 buffer_offset,u32 buffer_length)209 void vbva_setup_buffer_context(struct vbva_buf_ctx *vbva_ctx,
210 u32 buffer_offset, u32 buffer_length)
211 {
212 vbva_ctx->buffer_offset = buffer_offset;
213 vbva_ctx->buffer_length = buffer_length;
214 }
215