virtio-gpu: Add udmabuf helpers

Add helper functions to create a dmabuf for a resource and mmap it.
Also, introduce the fields blob and blob_size so that these helpers
can start to use them but the full picture will emerge only after
adding create_blob API in patch 8 of this series.

To be able to create a dmabuf using the udmabuf driver, Qemu needs
to be lauched with the memfd memory backend like this:

qemu-system-x86_64 -m 8192m -object memory-backend-memfd,id=mem1,size=8192M
-machine memory-backend=mem1

Based-on-patch-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Message-Id: <20210526231429.1045476-4-vivek.kasireddy@intel.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
index 8ca2c55d9a..265b1c516c 100644
--- a/include/hw/virtio/virtio-gpu.h
+++ b/include/hw/virtio/virtio-gpu.h
@@ -50,6 +50,12 @@ struct virtio_gpu_simple_resource {
     uint32_t scanout_bitmask;
     pixman_image_t *image;
     uint64_t hostmem;
+
+    uint64_t blob_size;
+    void *blob;
+    int dmabuf_fd;
+    uint8_t *remapped;
+
     QTAILQ_ENTRY(virtio_gpu_simple_resource) next;
 };
 
@@ -238,6 +244,11 @@ void virtio_gpu_update_cursor_data(VirtIOGPU *g,
                                    struct virtio_gpu_scanout *s,
                                    uint32_t resource_id);
 
+/* virtio-gpu-udmabuf.c */
+bool virtio_gpu_have_udmabuf(void);
+void virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res);
+void virtio_gpu_fini_udmabuf(struct virtio_gpu_simple_resource *res);
+
 /* virtio-gpu-3d.c */
 void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
                                   struct virtio_gpu_ctrl_command *cmd);