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 https://www.burtleburtle.net/bob/hash/doobs.html */ 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 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 */ 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 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 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 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