virtio-gpu/win32: allocate shareable 2d resources/images

Allocate pixman bits for scanouts with qemu_win32_map_alloc() so we can
set a shareable handle on the associated display surface.

Note: when bits are provided to pixman_image_create_bits(), you must also give
the rowstride (the argument is ignored when bits is NULL)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230606115658.677673-11-marcandre.lureau@redhat.com>

hw/display/virtio-gpu.c

@@ -258,6 +258,16 @@ static uint32_t calc_image_hostmem(pixman_format_code_t pformat,
     return height * stride;
 }
 
+#ifdef WIN32
+static void
+win32_pixman_image_destroy(pixman_image_t *image, void *data)
+{
+    HANDLE handle = data;
+
+    qemu_win32_map_free(pixman_image_get_data(image), handle, &error_warn);
+}
+#endif
+
 static void virtio_gpu_resource_create_2d(VirtIOGPU *g,
                                           struct virtio_gpu_ctrl_command *cmd)
 {
@@ -304,12 +314,27 @@ static void virtio_gpu_resource_create_2d(VirtIOGPU *g,
 
     res->hostmem = calc_image_hostmem(pformat, c2d.width, c2d.height);
     if (res->hostmem + g->hostmem < g->conf_max_hostmem) {
+        void *bits = NULL;
+#ifdef WIN32
+        bits = qemu_win32_map_alloc(res->hostmem, &res->handle, &error_warn);
+        if (!bits) {
+            goto end;
+        }
+#endif
         res->image = pixman_image_create_bits(pformat,
                                               c2d.width,
                                               c2d.height,
-                                              NULL, 0);
+                                              bits, res->hostmem / c2d.height);
+#ifdef WIN32
+        if (res->image) {
+            pixman_image_set_destroy_function(res->image, win32_pixman_image_destroy, res->handle);
+        }
+#endif
     }
 
+#ifdef WIN32
+end:
+#endif
     if (!res->image) {
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: resource creation failed %d %d %d\n",
@@ -685,6 +710,9 @@ static void virtio_gpu_do_set_scanout(VirtIOGPU *g,
             *error = VIRTIO_GPU_RESP_ERR_UNSPEC;
             return;
         }
+#ifdef WIN32
+        qemu_displaysurface_win32_set_handle(scanout->ds, res->handle, fb->offset);
+#endif
 
         pixman_image_unref(rect);
         dpy_gfx_replace_surface(g->parent_obj.scanout[scanout_id].con,
@@ -1228,6 +1256,7 @@ static int virtio_gpu_load(QEMUFile *f, void *opaque, size_t size,
     struct virtio_gpu_simple_resource *res;
     struct virtio_gpu_scanout *scanout;
     uint32_t resource_id, pformat;
+    void *bits = NULL;
     int i;
 
     g->hostmem = 0;
@@ -1252,15 +1281,23 @@ static int virtio_gpu_load(QEMUFile *f, void *opaque, size_t size,
             g_free(res);
             return -EINVAL;
         }
+
+        res->hostmem = calc_image_hostmem(pformat, res->width, res->height);
+#ifdef WIN32
+        bits = qemu_win32_map_alloc(res->hostmem, &res->handle, &error_warn);
+        if (!bits) {
+            g_free(res);
+            return -EINVAL;
+        }
+#endif
         res->image = pixman_image_create_bits(pformat,
                                               res->width, res->height,
-                                              NULL, 0);
+                                              bits, res->hostmem / res->height);
         if (!res->image) {
             g_free(res);
             return -EINVAL;
         }
 
-        res->hostmem = calc_image_hostmem(pformat, res->width, res->height);
 
         res->addrs = g_new(uint64_t, res->iov_cnt);
         res->iov = g_new(struct iovec, res->iov_cnt);
@@ -1321,6 +1358,9 @@ static int virtio_gpu_load(QEMUFile *f, void *opaque, size_t size,
         if (!scanout->ds) {
             return -EINVAL;
         }
+#ifdef WIN32
+        qemu_displaysurface_win32_set_handle(scanout->ds, res->handle, 0);
+#endif
 
         dpy_gfx_replace_surface(scanout->con, scanout->ds);
         dpy_gfx_update_full(scanout->con);

include/hw/virtio/virtio-gpu.h

@@ -48,6 +48,9 @@ struct virtio_gpu_simple_resource {
     unsigned int iov_cnt;
     uint32_t scanout_bitmask;
     pixman_image_t *image;
+#ifdef WIN32
+    HANDLE handle;
+#endif
     uint64_t hostmem;
 
     uint64_t blob_size;