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1// SPDX-License-Identifier: MIT2/*3 * Copyright (C) 2017 Oracle Corporation4 * 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 */12static 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 23static 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 */33static 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 47void *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 74void 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 84int 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