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// SPDX-License-Identifier: MIT
/*
* Copyright (C) 2017 Oracle Corporation
* Authors: Hans de Goede <hdegoede@redhat.com>
*/
#include "vbox_drv.h"
#include "vboxvideo_vbe.h"
#include "hgsmi_defs.h"
/* One-at-a-Time Hash from https://www.burtleburtle.net/bob/hash/doobs.html */
static u32 hgsmi_hash_process(u32 hash, const u8 *data, int size)
{
while (size--) {
hash += *data++;
hash += (hash << 10);
hash ^= (hash >> 6);
}
return hash;
}
static u32 hgsmi_hash_end(u32 hash)
{
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return hash;
}
/* Not really a checksum but that is the naming used in all vbox code */
static u32 hgsmi_checksum(u32 offset,
const struct hgsmi_buffer_header *header,
const struct hgsmi_buffer_tail *tail)
{
u32 checksum;
checksum = hgsmi_hash_process(0, (u8 *)&offset, sizeof(offset));
checksum = hgsmi_hash_process(checksum, (u8 *)header, sizeof(*header));
/* 4 -> Do not checksum the checksum itself */
checksum = hgsmi_hash_process(checksum, (u8 *)tail, 4);
return hgsmi_hash_end(checksum);
}
void *hgsmi_buffer_alloc(struct gen_pool *guest_pool, size_t size,
u8 channel, u16 channel_info)
{
struct hgsmi_buffer_header *h;
struct hgsmi_buffer_tail *t;
size_t total_size;
dma_addr_t offset;
total_size = size + sizeof(*h) + sizeof(*t);
h = gen_pool_dma_alloc(guest_pool, total_size, &offset);
if (!h)
return NULL;
t = (struct hgsmi_buffer_tail *)((u8 *)h + sizeof(*h) + size);
h->flags = HGSMI_BUFFER_HEADER_F_SEQ_SINGLE;
h->data_size = size;
h->channel = channel;
h->channel_info = channel_info;
memset(&h->u.header_data, 0, sizeof(h->u.header_data));
t->reserved = 0;
t->checksum = hgsmi_checksum(offset, h, t);
return (u8 *)h + sizeof(*h);
}
void hgsmi_buffer_free(struct gen_pool *guest_pool, void *buf)
{
struct hgsmi_buffer_header *h =
(struct hgsmi_buffer_header *)((u8 *)buf - sizeof(*h));
size_t total_size = h->data_size + sizeof(*h) +
sizeof(struct hgsmi_buffer_tail);
gen_pool_free(guest_pool, (unsigned long)h, total_size);
}
int hgsmi_buffer_submit(struct gen_pool *guest_pool, void *buf)
{
phys_addr_t offset;
offset = gen_pool_virt_to_phys(guest_pool, (unsigned long)buf -
sizeof(struct hgsmi_buffer_header));
outl(offset, VGA_PORT_HGSMI_GUEST);
/* Make the compiler aware that the host has changed memory. */
mb();
return 0;
}
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