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ui/virtio-gpu: add and use qemu_create_displaysurface_pixman

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Add a the new qemu_create_displaysurface_pixman function, to create
a DisplaySurface backed by an existing pixman image.  In that case
there is no need to create a new pixman image pointing to the same
backing storage.  We can just use the existing image directly.

This does not only simplify things a bit, but most importantly it
gets the reference counting right, so the backing storage for the
pixman image wouldn't be released underneath us.

Use new function in virtio-gpu, where using it actually fixes
use-after-free crashes.

Cc: qemu-stable@nongnu.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 1459499240-742-1-git-send-email-kraxel@redhat.com
This commit is contained in:
Gerd Hoffmann 2016-04-01 10:27:20 +02:00
parent 9628af036f
commit ca58b45fbe
4 changed files with 14 additions and 4 deletions
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5
hw/display/virtio-gpu.c
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@ -572,10 +572,7 @@ static void virtio_gpu_set_scanout(VirtIOGPU *g,
scanout->width != ss.r.width ||
scanout->height != ss.r.height) {
/* realloc the surface ptr */
scanout->ds = qemu_create_displaysurface_from
(ss.r.width, ss.r.height, format,
pixman_image_get_stride(res->image),
(uint8_t *)pixman_image_get_data(res->image) + offset);
scanout->ds = qemu_create_displaysurface_pixman(res->image);
if (!scanout->ds) {
cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
return;

1
include/ui/console.h
View File

@ -234,6 +234,7 @@ DisplayState *init_displaystate(void);
DisplaySurface *qemu_create_displaysurface_from(int width, int height,
pixman_format_code_t format,
int linesize, uint8_t *data);
DisplaySurface *qemu_create_displaysurface_pixman(pixman_image_t *image);
DisplaySurface *qemu_create_displaysurface_guestmem(int width, int height,
pixman_format_code_t format,
int linesize,

1
trace-events
View File

@ -1161,6 +1161,7 @@ console_select(int nr) "%d"
console_refresh(int interval) "interval %d ms"
displaysurface_create(void *display_surface, int w, int h) "surface=%p, %dx%d"
displaysurface_create_from(void *display_surface, int w, int h, uint32_t format) "surface=%p, %dx%d, format 0x%x"
displaysurface_create_pixman(void *display_surface) "surface=%p"
displaysurface_free(void *display_surface) "surface=%p"
displaychangelistener_register(void *dcl, const char *name) "%p [ %s ]"
displaychangelistener_unregister(void *dcl, const char *name) "%p [ %s ]"

11
ui/console.c
View File

@ -1292,6 +1292,17 @@ DisplaySurface *qemu_create_displaysurface_from(int width, int height,
return surface;
}
DisplaySurface *qemu_create_displaysurface_pixman(pixman_image_t *image)
{
DisplaySurface *surface = g_new0(DisplaySurface, 1);
trace_displaysurface_create_pixman(surface);
surface->format = pixman_image_get_format(image);
surface->image = pixman_image_ref(image);
return surface;
}
static void qemu_unmap_displaysurface_guestmem(pixman_image_t *image,
void *unused)
{