1 // SPDX-License-Identifier: MIT
2 /*
3 * Copyright (C) 2017 Oracle Corporation
4 * Authors: Hans de Goede <hdegoede@redhat.com>
5 */
6
7 #include "vbox_drv.h"
8 #include "vboxvideo_vbe.h"
9 #include "hgsmi_defs.h"
10
11 /* One-at-a-Time Hash from http://www.burtleburtle.net/bob/hash/doobs.html */
hgsmi_hash_process(u32 hash,const u8 * data,int size)12 static u32 hgsmi_hash_process(u32 hash, const u8 *data, int size)
13 {
14 while (size--) {
15 hash += *data++;
16 hash += (hash << 10);
17 hash ^= (hash >> 6);
18 }
19
20 return hash;
21 }
22
hgsmi_hash_end(u32 hash)23 static u32 hgsmi_hash_end(u32 hash)
24 {
25 hash += (hash << 3);
26 hash ^= (hash >> 11);
27 hash += (hash << 15);
28
29 return hash;
30 }
31
32 /* Not really a checksum but that is the naming used in all vbox code */
hgsmi_checksum(u32 offset,const struct hgsmi_buffer_header * header,const struct hgsmi_buffer_tail * tail)33 static u32 hgsmi_checksum(u32 offset,
34 const struct hgsmi_buffer_header *header,
35 const struct hgsmi_buffer_tail *tail)
36 {
37 u32 checksum;
38
39 checksum = hgsmi_hash_process(0, (u8 *)&offset, sizeof(offset));
40 checksum = hgsmi_hash_process(checksum, (u8 *)header, sizeof(*header));
41 /* 4 -> Do not checksum the checksum itself */
42 checksum = hgsmi_hash_process(checksum, (u8 *)tail, 4);
43
44 return hgsmi_hash_end(checksum);
45 }
46
hgsmi_buffer_alloc(struct gen_pool * guest_pool,size_t size,u8 channel,u16 channel_info)47 void *hgsmi_buffer_alloc(struct gen_pool *guest_pool, size_t size,
48 u8 channel, u16 channel_info)
49 {
50 struct hgsmi_buffer_header *h;
51 struct hgsmi_buffer_tail *t;
52 size_t total_size;
53 dma_addr_t offset;
54
55 total_size = size + sizeof(*h) + sizeof(*t);
56 h = gen_pool_dma_alloc(guest_pool, total_size, &offset);
57 if (!h)
58 return NULL;
59
60 t = (struct hgsmi_buffer_tail *)((u8 *)h + sizeof(*h) + size);
61
62 h->flags = HGSMI_BUFFER_HEADER_F_SEQ_SINGLE;
63 h->data_size = size;
64 h->channel = channel;
65 h->channel_info = channel_info;
66 memset(&h->u.header_data, 0, sizeof(h->u.header_data));
67
68 t->reserved = 0;
69 t->checksum = hgsmi_checksum(offset, h, t);
70
71 return (u8 *)h + sizeof(*h);
72 }
73
hgsmi_buffer_free(struct gen_pool * guest_pool,void * buf)74 void hgsmi_buffer_free(struct gen_pool *guest_pool, void *buf)
75 {
76 struct hgsmi_buffer_header *h =
77 (struct hgsmi_buffer_header *)((u8 *)buf - sizeof(*h));
78 size_t total_size = h->data_size + sizeof(*h) +
79 sizeof(struct hgsmi_buffer_tail);
80
81 gen_pool_free(guest_pool, (unsigned long)h, total_size);
82 }
83
hgsmi_buffer_submit(struct gen_pool * guest_pool,void * buf)84 int hgsmi_buffer_submit(struct gen_pool *guest_pool, void *buf)
85 {
86 phys_addr_t offset;
87
88 offset = gen_pool_virt_to_phys(guest_pool, (unsigned long)buf -
89 sizeof(struct hgsmi_buffer_header));
90 outl(offset, VGA_PORT_HGSMI_GUEST);
91 /* Make the compiler aware that the host has changed memory. */
92 mb();
93
94 return 0;
95 }
96
