RE: [PATCH v10 2/6] ui/console: new dmabuf.h and dmabuf.c for QemuDmaBuf struct and helpers

[Kim, Dongwon]

Hi Daniel,

> -----Original Message-----
> From: Daniel P. Berrangé <berrange@redhat.com>
> Sent: Tuesday, April 23, 2024 7:07 AM
> To: Kim, Dongwon <dongwon.kim@intel.com>
> Cc: qemu-devel@nongnu.org; marcandre.lureau@redhat.com;
> philmd@linaro.org
> Subject: Re: [PATCH v10 2/6] ui/console: new dmabuf.h and dmabuf.c for
> QemuDmaBuf struct and helpers
> 
> On Mon, Apr 22, 2024 at 07:22:49PM -0700, dongwon.kim@intel.com wrote:
> > From: Dongwon Kim <dongwon.kim@intel.com>
> >
> > New header and source files are added for containing QemuDmaBuf struct
> > definition and newly introduced helpers for creating/freeing the
> > struct and accessing its data.
> >
> > v10: Change the license type for both dmabuf.h and dmabuf.c from MIT to
> >      GPL to be in line with QEMU's default license
> >      (Daniel P. Berrangé <berrange@redhat.com>)
> >
> > Suggested-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
> > Cc: Daniel P. Berrangé <berrange@redhat.com>
> > Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
> > Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
> > ---
> >  include/ui/console.h |  20 +----
> >  include/ui/dmabuf.h  |  64 +++++++++++++++
> >  ui/dmabuf.c          | 189 +++++++++++++++++++++++++++++++++++++++++++
> >  ui/meson.build       |   1 +
> >  4 files changed, 255 insertions(+), 19 deletions(-)  create mode
> > 100644 include/ui/dmabuf.h  create mode 100644 ui/dmabuf.c
> >
> > diff --git a/include/ui/console.h b/include/ui/console.h index
> > 0bc7a00ac0..a208a68b88 100644
> > --- a/include/ui/console.h
> > +++ b/include/ui/console.h
> > @@ -7,6 +7,7 @@
> >  #include "qapi/qapi-types-ui.h"
> >  #include "ui/input.h"
> >  #include "ui/surface.h"
> > +#include "ui/dmabuf.h"
> >
> >  #define TYPE_QEMU_CONSOLE "qemu-console"
> >  OBJECT_DECLARE_TYPE(QemuConsole, QemuConsoleClass, QEMU_CONSOLE)
> @@
> > -185,25 +186,6 @@ struct QEMUGLParams {
> >      int minor_ver;
> >  };
> >
> > -typedef struct QemuDmaBuf {
> > -    int       fd;
> > -    uint32_t  width;
> > -    uint32_t  height;
> > -    uint32_t  stride;
> > -    uint32_t  fourcc;
> > -    uint64_t  modifier;
> > -    uint32_t  texture;
> > -    uint32_t  x;
> > -    uint32_t  y;
> > -    uint32_t  backing_width;
> > -    uint32_t  backing_height;
> > -    bool      y0_top;
> > -    void      *sync;
> > -    int       fence_fd;
> > -    bool      allow_fences;
> > -    bool      draw_submitted;
> > -} QemuDmaBuf;
> > -
> >  enum display_scanout {
> >      SCANOUT_NONE,
> >      SCANOUT_SURFACE,
> > diff --git a/include/ui/dmabuf.h b/include/ui/dmabuf.h new file mode
> > 100644 index 0000000000..7a60116ee6
> > --- /dev/null
> > +++ b/include/ui/dmabuf.h
> > @@ -0,0 +1,64 @@
> > +/*
> > + * SPDX-License-Identifier: GPL-2.0-or-later
> > + *
> > + * QemuDmaBuf struct and helpers used for accessing its data
> > + *
> > + * This work is licensed under the terms of the GNU GPL, version 2 or 
> > later.
> > + * See the COPYING file in the top-level directory.
> > + */
> > +
> > +#ifndef DMABUF_H
> > +#define DMABUF_H
> > +
> > +typedef struct QemuDmaBuf {
> > +    int       fd;
> > +    uint32_t  width;
> > +    uint32_t  height;
> > +    uint32_t  stride;
> > +    uint32_t  fourcc;
> > +    uint64_t  modifier;
> > +    uint32_t  texture;
> > +    uint32_t  x;
> > +    uint32_t  y;
> > +    uint32_t  backing_width;
> > +    uint32_t  backing_height;
> > +    bool      y0_top;
> > +    void      *sync;
> > +    int       fence_fd;
> > +    bool      allow_fences;
> > +    bool      draw_submitted;
> > +} QemuDmaBuf;
> > +
> > +QemuDmaBuf *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, int32_t
> > +dmabuf_fd,
> 
> Should be 'int' not 'int32_t' for FDs.
> 
> > +                                   bool allow_fences, bool y0_top);
> > +void qemu_dmabuf_free(QemuDmaBuf *dmabuf);
> > +
> > +G_DEFINE_AUTOPTR_CLEANUP_FUNC(QemuDmaBuf, qemu_dmabuf_free);
> > +
> > +int32_t qemu_dmabuf_get_fd(QemuDmaBuf *dmabuf);
> 
> Again should be 'int' not 'int42_t'
> 
> I think there ought to also be a
> 
>   int qemu_dmabuf_dup_fd(QemuDmaBuf *dmabuf);
> 
> to do the dup() call in one go too
> 
> > diff --git a/ui/dmabuf.c b/ui/dmabuf.c new file mode 100644 index
> > 0000000000..f447cce4fe
> > --- /dev/null
> > +++ b/ui/dmabuf.c
> 
> > +
> > +void qemu_dmabuf_free(QemuDmaBuf *dmabuf)
> > +{
> > +    if (dmabuf == NULL) {
> > +        return;
> > +    }
> > +
> 
> I think this method should be made to call
> 
>   qemu_dmabuf_close()
> 
> to release the FD, if not already released, otherwise
> this method could be a resource leak.

[Kim, Dongwon]  Daniel, I initially agreed with you on the idea that is we 
should close dmabuf->fd here in freeing routine and I already submitted v11 
containing that change but I just found it causes some regression at least for 
virtio-gpu case because this fd is for udmabuf bound to the actual resource. 
This is designed to be closed by virtio-gpu when the resource is freed, not 
when QemuDmaBuf struct referencing that resource (udmabuf) is freed. So I guess 
we need to split free and close here.  I will work on v12 but I will wait for 
your feedback before submitting it.

Thanks!
> 
> > +    g_free(dmabuf);
> > +}
> > +
> 
> With regards,
> Daniel
> --
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