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// SPDX-License-Identifier: MIT
/* Copyright (C) 2006-2017 Oracle Corporation */
#include <linux/vbox_err.h>
#include "vbox_drv.h"
#include "vboxvideo_guest.h"
#include "hgsmi_channels.h"
/*
* There is a hardware ring buffer in the graphics device video RAM, formerly
* in the VBox VMMDev PCI memory space.
* All graphics commands go there serialized by vbva_buffer_begin_update.
* and vbva_buffer_end_update.
*
* free_offset is writing position. data_offset is reading position.
* free_offset == data_offset means buffer is empty.
* There must be always gap between data_offset and free_offset when data
* are in the buffer.
* Guest only changes free_offset, host changes data_offset.
*/
static u32 vbva_buffer_available(const struct vbva_buffer *vbva)
{
s32 diff = vbva->data_offset - vbva->free_offset;
return diff > 0 ? diff : vbva->data_len + diff;
}
static void vbva_buffer_place_data_at(struct vbva_buf_ctx *vbva_ctx,
const void *p, u32 len, u32 offset)
{
struct vbva_buffer *vbva = vbva_ctx->vbva;
u32 bytes_till_boundary = vbva->data_len - offset;
u8 *dst = &vbva->data[offset];
s32 diff = len - bytes_till_boundary;
if (diff <= 0) {
/* Chunk will not cross buffer boundary. */
memcpy(dst, p, len);
} else {
/* Chunk crosses buffer boundary. */
memcpy(dst, p, bytes_till_boundary);
memcpy(&vbva->data[0], (u8 *)p + bytes_till_boundary, diff);
}
}
static void vbva_buffer_flush(struct gen_pool *ctx)
{
struct vbva_flush *p;
p = hgsmi_buffer_alloc(ctx, sizeof(*p), HGSMI_CH_VBVA, VBVA_FLUSH);
if (!p)
return;
p->reserved = 0;
hgsmi_buffer_submit(ctx, p);
hgsmi_buffer_free(ctx, p);
}
bool vbva_write(struct vbva_buf_ctx *vbva_ctx, struct gen_pool *ctx,
const void *p, u32 len)
{
struct vbva_record *record;
struct vbva_buffer *vbva;
u32 available;
vbva = vbva_ctx->vbva;
record = vbva_ctx->record;
if (!vbva || vbva_ctx->buffer_overflow ||
!record || !(record->len_and_flags & VBVA_F_RECORD_PARTIAL))
return false;
available = vbva_buffer_available(vbva);
while (len > 0) {
u32 chunk = len;
if (chunk >= available) {
vbva_buffer_flush(ctx);
available = vbva_buffer_available(vbva);
}
if (chunk >= available) {
if (WARN_ON(available <= vbva->partial_write_tresh)) {
vbva_ctx->buffer_overflow = true;
return false;
}
chunk = available - vbva->partial_write_tresh;
}
vbva_buffer_place_data_at(vbva_ctx, p, chunk,
vbva->free_offset);
vbva->free_offset = (vbva->free_offset + chunk) %
vbva->data_len;
record->len_and_flags += chunk;
available -= chunk;
len -= chunk;
p += chunk;
}
return true;
}
static bool vbva_inform_host(struct vbva_buf_ctx *vbva_ctx,
struct gen_pool *ctx, s32 screen, bool enable)
{
struct vbva_enable_ex *p;
bool ret;
p = hgsmi_buffer_alloc(ctx, sizeof(*p), HGSMI_CH_VBVA, VBVA_ENABLE);
if (!p)
return false;
p->base.flags = enable ? VBVA_F_ENABLE : VBVA_F_DISABLE;
p->base.offset = vbva_ctx->buffer_offset;
p->base.result = VERR_NOT_SUPPORTED;
if (screen >= 0) {
p->base.flags |= VBVA_F_EXTENDED | VBVA_F_ABSOFFSET;
p->screen_id = screen;
}
hgsmi_buffer_submit(ctx, p);
if (enable)
ret = p->base.result >= 0;
else
ret = true;
hgsmi_buffer_free(ctx, p);
return ret;
}
bool vbva_enable(struct vbva_buf_ctx *vbva_ctx, struct gen_pool *ctx,
struct vbva_buffer *vbva, s32 screen)
{
bool ret = false;
memset(vbva, 0, sizeof(*vbva));
vbva->partial_write_tresh = 256;
vbva->data_len = vbva_ctx->buffer_length - sizeof(struct vbva_buffer);
vbva_ctx->vbva = vbva;
ret = vbva_inform_host(vbva_ctx, ctx, screen, true);
if (!ret)
vbva_disable(vbva_ctx, ctx, screen);
return ret;
}
void vbva_disable(struct vbva_buf_ctx *vbva_ctx, struct gen_pool *ctx,
s32 screen)
{
vbva_ctx->buffer_overflow = false;
vbva_ctx->record = NULL;
vbva_ctx->vbva = NULL;
vbva_inform_host(vbva_ctx, ctx, screen, false);
}
bool vbva_buffer_begin_update(struct vbva_buf_ctx *vbva_ctx,
struct gen_pool *ctx)
{
struct vbva_record *record;
u32 next;
if (!vbva_ctx->vbva ||
!(vbva_ctx->vbva->host_flags.host_events & VBVA_F_MODE_ENABLED))
return false;
WARN_ON(vbva_ctx->buffer_overflow || vbva_ctx->record);
next = (vbva_ctx->vbva->record_free_index + 1) % VBVA_MAX_RECORDS;
/* Flush if all slots in the records queue are used */
if (next == vbva_ctx->vbva->record_first_index)
vbva_buffer_flush(ctx);
/* If even after flush there is no place then fail the request */
if (next == vbva_ctx->vbva->record_first_index)
return false;
record = &vbva_ctx->vbva->records[vbva_ctx->vbva->record_free_index];
record->len_and_flags = VBVA_F_RECORD_PARTIAL;
vbva_ctx->vbva->record_free_index = next;
/* Remember which record we are using. */
vbva_ctx->record = record;
return true;
}
void vbva_buffer_end_update(struct vbva_buf_ctx *vbva_ctx)
{
struct vbva_record *record = vbva_ctx->record;
WARN_ON(!vbva_ctx->vbva || !record ||
!(record->len_and_flags & VBVA_F_RECORD_PARTIAL));
/* Mark the record completed. */
record->len_and_flags &= ~VBVA_F_RECORD_PARTIAL;
vbva_ctx->buffer_overflow = false;
vbva_ctx->record = NULL;
}
void vbva_setup_buffer_context(struct vbva_buf_ctx *vbva_ctx,
u32 buffer_offset, u32 buffer_length)
{
vbva_ctx->buffer_offset = buffer_offset;
vbva_ctx->buffer_length = buffer_length;
}
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