qemu/hw/display/ramfb.c
Gerd Hoffmann 3fcf15df00 ramfb: fix size calculation
size calculation isn't correct with guest-supplied stride, the last
display line isn't accounted for correctly.

For the typical case of stride > linesize (add padding) we error on the
safe side (calculated size is larger than actual size).

With stride < linesize (scanlines overlap) the calculated size is
smaller than the actual size though so our guest memory mapping might
end up being too small.

While being at it also fix ramfb_create_display_surface to use hwaddr
for the parameters.  That way all calculation are done with hwaddr type
and we can't get funny effects from type castings.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 20200429115236.28709-7-kraxel@redhat.com
2020-05-18 15:43:51 +02:00

136 lines
3.5 KiB
C

/*
* early boot framebuffer in guest ram
* configured using fw_cfg
*
* Copyright Red Hat, Inc. 2017
*
* Author:
* Gerd Hoffmann <kraxel@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "hw/loader.h"
#include "hw/display/ramfb.h"
#include "hw/display/bochs-vbe.h" /* for limits */
#include "ui/console.h"
#include "sysemu/reset.h"
struct QEMU_PACKED RAMFBCfg {
uint64_t addr;
uint32_t fourcc;
uint32_t flags;
uint32_t width;
uint32_t height;
uint32_t stride;
};
struct RAMFBState {
DisplaySurface *ds;
uint32_t width, height;
struct RAMFBCfg cfg;
};
static void ramfb_unmap_display_surface(pixman_image_t *image, void *unused)
{
void *data = pixman_image_get_data(image);
uint32_t size = pixman_image_get_stride(image) *
pixman_image_get_height(image);
cpu_physical_memory_unmap(data, size, 0, 0);
}
static DisplaySurface *ramfb_create_display_surface(int width, int height,
pixman_format_code_t format,
hwaddr stride, hwaddr addr)
{
DisplaySurface *surface;
hwaddr size, mapsize, linesize;
void *data;
if (width < 16 || width > VBE_DISPI_MAX_XRES ||
height < 16 || height > VBE_DISPI_MAX_YRES ||
format == 0 /* unknown format */)
return NULL;
linesize = width * PIXMAN_FORMAT_BPP(format) / 8;
if (stride == 0) {
stride = linesize;
}
mapsize = size = stride * (height - 1) + linesize;
data = cpu_physical_memory_map(addr, &mapsize, false);
if (size != mapsize) {
cpu_physical_memory_unmap(data, mapsize, 0, 0);
return NULL;
}
surface = qemu_create_displaysurface_from(width, height,
format, stride, data);
pixman_image_set_destroy_function(surface->image,
ramfb_unmap_display_surface, NULL);
return surface;
}
static void ramfb_fw_cfg_write(void *dev, off_t offset, size_t len)
{
RAMFBState *s = dev;
DisplaySurface *surface;
uint32_t fourcc, format, width, height;
hwaddr stride, addr;
width = be32_to_cpu(s->cfg.width);
height = be32_to_cpu(s->cfg.height);
stride = be32_to_cpu(s->cfg.stride);
fourcc = be32_to_cpu(s->cfg.fourcc);
addr = be64_to_cpu(s->cfg.addr);
format = qemu_drm_format_to_pixman(fourcc);
surface = ramfb_create_display_surface(width, height,
format, stride, addr);
if (!surface) {
return;
}
s->width = width;
s->height = height;
s->ds = surface;
}
void ramfb_display_update(QemuConsole *con, RAMFBState *s)
{
if (!s->width || !s->height) {
return;
}
if (s->ds) {
dpy_gfx_replace_surface(con, s->ds);
s->ds = NULL;
}
/* simple full screen update */
dpy_gfx_update_full(con);
}
RAMFBState *ramfb_setup(Error **errp)
{
FWCfgState *fw_cfg = fw_cfg_find();
RAMFBState *s;
if (!fw_cfg || !fw_cfg->dma_enabled) {
error_setg(errp, "ramfb device requires fw_cfg with DMA");
return NULL;
}
s = g_new0(RAMFBState, 1);
rom_add_vga("vgabios-ramfb.bin");
fw_cfg_add_file_callback(fw_cfg, "etc/ramfb",
NULL, ramfb_fw_cfg_write, s,
&s->cfg, sizeof(s->cfg), false);
return s;
}