Re: [PATCH v6 3/3] ui/console: Introduce dpy_gl_qemu_dmabuf_new() and free() helpers

[Daniel P . Berrangé]

On Tue, Apr 16, 2024 at 09:09:54PM -0700, dongwon.kim@intel.com wrote:
> From: Dongwon Kim <dongwon.kim@intel.com>
> 
> This commit introduces utility functions for the creation and deallocation
> of QemuDmaBuf instances. Additionally, it updates all relevant sections
> of the codebase to utilize these new utility functions.
> 
> Suggested-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
> Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
> Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
> ---
>  include/hw/vfio/vfio-common.h   |  2 +-
>  include/hw/virtio/virtio-gpu.h  |  4 ++--
>  include/ui/console.h            |  8 +++++++-
>  hw/display/vhost-user-gpu.c     | 32 +++++++++++++++++--------------
>  hw/display/virtio-gpu-udmabuf.c | 24 +++++++++--------------
>  hw/vfio/display.c               | 26 ++++++++++++-------------
>  ui/console.c                    | 34 +++++++++++++++++++++++++++++++++
>  ui/dbus-listener.c              | 28 ++++++++++++---------------
>  8 files changed, 95 insertions(+), 63 deletions(-)
> 
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index b9da6c08ef..d66e27db02 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -148,7 +148,7 @@ typedef struct VFIOGroup {
>  } VFIOGroup;
>  
>  typedef struct VFIODMABuf {
> -    QemuDmaBuf buf;
> +    QemuDmaBuf *buf;
>      uint32_t pos_x, pos_y, pos_updates;
>      uint32_t hot_x, hot_y, hot_updates;
>      int dmabuf_id;
> diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
> index ed44cdad6b..56d6e821bf 100644
> --- a/include/hw/virtio/virtio-gpu.h
> +++ b/include/hw/virtio/virtio-gpu.h
> @@ -169,7 +169,7 @@ struct VirtIOGPUBaseClass {
>      DEFINE_PROP_UINT32("yres", _state, _conf.yres, 800)
>  
>  typedef struct VGPUDMABuf {
> -    QemuDmaBuf buf;
> +    QemuDmaBuf *buf;
>      uint32_t scanout_id;
>      QTAILQ_ENTRY(VGPUDMABuf) next;
>  } VGPUDMABuf;
> @@ -238,7 +238,7 @@ struct VhostUserGPU {
>      VhostUserBackend *vhost;
>      int vhost_gpu_fd; /* closed by the chardev */
>      CharBackend vhost_chr;
> -    QemuDmaBuf dmabuf[VIRTIO_GPU_MAX_SCANOUTS];
> +    QemuDmaBuf *dmabuf[VIRTIO_GPU_MAX_SCANOUTS];
>      bool backend_blocked;
>  };
>  
> diff --git a/include/ui/console.h b/include/ui/console.h
> index 3d9d8b9fce..6d7c03b7c5 100644
> --- a/include/ui/console.h
> +++ b/include/ui/console.h
> @@ -358,7 +358,13 @@ void dpy_gl_cursor_dmabuf(QemuConsole *con, QemuDmaBuf 
> *dmabuf,
>                            bool have_hot, uint32_t hot_x, uint32_t hot_y);
>  void dpy_gl_cursor_position(QemuConsole *con,
>                              uint32_t pos_x, uint32_t pos_y);
> -
> +QemuDmaBuf *dpy_gl_qemu_dmabuf_new(uint32_t width, uint32_t height,
> +                                   uint32_t stride, uint32_t x,
> +                                   uint32_t y, uint32_t backing_width,
> +                                   uint32_t backing_height, uint32_t fourcc,
> +                                   uint64_t modifier, uint32_t dmabuf_fd,
> +                                   bool allow_fences, bool y0_top);
> +void dpy_gl_qemu_dmabuf_free(QemuDmaBuf *dmabuf);

Since you're creating a new allocator/deallocator pair for
this, please also call G_DEFINE_AUTOPTR_CLEANUP_FUNC so this
struct becomes usable with g_autoptr(), even if we don't
currently have an immediate need to use g_autoptr.

>  int32_t dpy_gl_qemu_dmabuf_get_fd(QemuDmaBuf *dmabuf);
>  uint32_t dpy_gl_qemu_dmabuf_get_width(QemuDmaBuf *dmabuf);
>  uint32_t dpy_gl_qemu_dmabuf_get_height(QemuDmaBuf *dmabuf);


> diff --git a/ui/console.c b/ui/console.c
> index d4ca9e6e0f..ea23fd8af6 100644
> --- a/ui/console.c
> +++ b/ui/console.c
> @@ -1132,6 +1132,40 @@ void dpy_gl_cursor_position(QemuConsole *con,
>      }
>  }
>  
> +QemuDmaBuf *dpy_gl_qemu_dmabuf_new(uint32_t width, uint32_t height,
> +                                   uint32_t stride, uint32_t x,
> +                                   uint32_t y, uint32_t backing_width,
> +                                   uint32_t backing_height, uint32_t fourcc,
> +                                   uint64_t modifier, uint32_t dmabuf_fd,
> +                                   bool allow_fences, bool y0_top) {
> +    QemuDmaBuf *dmabuf;
> +
> +    dmabuf = g_new0(QemuDmaBuf, 1);
> +
> +    dmabuf->width = width;
> +    dmabuf->height = height;
> +    dmabuf->stride = stride;
> +    dmabuf->x = x;
> +    dmabuf->y = y;
> +    dmabuf->backing_width = backing_width;
> +    dmabuf->backing_height = backing_height;
> +    dmabuf->fourcc = fourcc;
> +    dmabuf->modifier = modifier;
> +    dmabuf->fd = dmabuf_fd;
> +    dmabuf->allow_fences = allow_fences;
> +    dmabuf->y0_top = y0_top;
> +    dmabuf->fence_fd = -1;
> +
> +    return dmabuf;
> +}
> +
> +void dpy_gl_qemu_dmabuf_free(QemuDmaBuf *dmabuf)
> +{
> +    assert(dmabuf != NULL);

It is normal practice for all XXX_free() funcs to
accept NULL as a valid argument, and operate as
a no-op. This makes code more robust, as it can
blindly call free without checking for NULL ahead
of time.

> +
> +    g_free(dmabuf);
> +}
> +

With regards,
Daniel
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