qemu虚拟显示器驱动代码实现
时间: 2023-10-22 07:21:36 浏览: 79
QEMU是一款开源的虚拟机软件,它支持模拟多种不同的硬件设备,包括虚拟显示器。在QEMU中,虚拟显示器驱动程序主要由以下两个部分组成:
1. 显示器后端(Display Backends):负责将客户机的图形数据渲染成显存中的像素数据,并将其发送给前端。
2. 显示器前端(Display Frontends):负责将后端发送的像素数据显示出来。
下面是一个简单的QEMU虚拟显示器驱动程序实现:
```c
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/module.h"
#include "ui/console.h"
#include "ui/console-input.h"
#include "ui/pixel_ops.h"
#include "hw/display/virtio-gpu.h"
#define TYPE_QEMU_DISPLAY "qemu-display"
#define QEMU_DISPLAY(obj) \
OBJECT_CHECK(QemuDisplayState, (obj), TYPE_QEMU_DISPLAY)
typedef struct QemuDisplayState {
VirtIOGPU *virtio_gpu;
DisplaySurface *surface;
Console *console;
uint8_t *fb;
int fb_stride;
} QemuDisplayState;
static void qemu_display_refresh(DisplayChangeListener *dcl,
const QRegion *region)
{
QemuDisplayState *s = QEMU_DISPLAY(dcl);
DisplaySurface *surface = s->surface;
int pos_x, pos_y;
uint8_t *fb = s->fb;
int fb_stride = s->fb_stride;
int width = surface->width;
int height = surface->height;
for (pos_y = 0; pos_y < height; pos_y++) {
for (pos_x = 0; pos_x < width; pos_x++) {
uint8_t *pixel = fb + pos_y * fb_stride + pos_x * 4;
uint32_t color = pixel_get(surface, pixel);
console_write_graphic(s->console, pos_x, pos_y, color);
}
}
}
static void qemu_display_destroy(DisplayChangeListener *dcl)
{
QemuDisplayState *s = QEMU_DISPLAY(dcl);
qemu_free(s->fb);
s->fb = NULL;
display_surface_unref(s->surface);
s->surface = NULL;
virtio_gpu_cleanup(s->virtio_gpu);
s->virtio_gpu = NULL;
}
static void qemu_display_init(DisplayChangeListener *dcl, DisplaySurface *surface,
int x, int y, int w, int h, int stride)
{
QemuDisplayState *s = QEMU_DISPLAY(dcl);
s->surface = surface;
s->console = graphic_console_init(surface->width, surface->height,
qemu_get_display_type());
s->fb_stride = surface->width * 4;
s->fb = qemu_mallocz(s->fb_stride * surface->height);
s->virtio_gpu = virtio_gpu_init(s->fb, s->fb_stride, surface->width,
surface->height);
}
static DisplayChangeListener *qemu_display_create(VirtIOGPU *virtio_gpu)
{
QemuDisplayState *s = qemu_mallocz(sizeof(QemuDisplayState));
DisplayChangeListener *dcl = display_state_create(s,
qemu_display_refresh,
qemu_display_destroy,
qemu_display_init);
s->virtio_gpu = virtio_gpu;
return dcl;
}
static void qemu_display_initfn(Object *obj)
{
DeviceState *dev = DEVICE(obj);
VirtIOGPU *virtio_gpu = VIRTIO_GPU(dev);
DisplayChangeListener *dcl = qemu_display_create(virtio_gpu);
display_state_set_surface(dcl, virtio_gpu_get_primary(virtio_gpu));
virtio_gpu_set_displaychange_listener(virtio_gpu, dcl);
}
static void qemu_display_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
VirtIOGPUClass *vgc = VIRTIO_GPU_CLASS(oc);
dc->reset = virtio_device_reset;
dc->vmsd = &vmstate_virtio_pci_device;
vgc->init_display = qemu_display_initfn;
}
static const TypeInfo qemu_display_info = {
.name = TYPE_QEMU_DISPLAY,
.parent = TYPE_VIRTIO_GPU,
.instance_size = sizeof(QemuDisplayState),
.class_init = qemu_display_class_init,
};
static void qemu_display_register_types(void)
{
type_register_static(&qemu_display_info);
}
type_init(qemu_display_register_types)
```
这个驱动程序实现了一个简单的QEMU虚拟显示器,它使用VirtIO-GPU协议与客户机进行通信。在初始化函数qemu_display_initfn中,驱动程序会创建一个DisplayChangeListener对象,并将其注册到virtio_gpu中。当客户机发送图形数据时,virtio_gpu会将数据传递给驱动程序的后端,并在显示内容更新时通知前端刷新显示。
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