[PATCH v10] vfio: ABI for mdev display dma-buf operation

[Zhang, Tina]

> -----Original Message-----
> From: Kirti Wankhede [mailto:kwankhede at nvidia.com]
> Sent: Thursday, July 6, 2017 10:02 PM
> To: Zhang, Tina <tina.zhang at intel.com>; alex.williamson at redhat.com;
> kraxel at redhat.com; chris at chris-wilson.co.uk; zhenyuw at linux.intel.com; Lv,
> Zhiyuan <zhiyuan.lv at intel.com>; Wang, Zhi A <zhi.a.wang at intel.com>; Tian,
> Kevin <kevin.tian at intel.com>; daniel at ffwll.ch
> Cc: intel-gfx at lists.freedesktop.org; intel-gvt-dev at lists.freedesktop.org; linux-
> kernel at vger.kernel.org
> Subject: Re: [PATCH v10] vfio: ABI for mdev display dma-buf operation
> 
> 
> 
> On 7/6/2017 3:59 AM, Tina Zhang wrote:
> > Add VFIO_DEVICE_QUERY_GFX_PLANE ioctl command to let user mode query
> > and get the plan and its related information.
> >
> > The dma-buf's life cycle is handled by user mode and tracked by kernel.
> > The returned fd in struct vfio_device_query_gfx_plane can be a new fd
> > or an old fd of a re-exported dma-buf. Host User mode can check the
> > value of fd and to see if it need to creat new resource according to
> > the new fd or just use the existed resource related to the old fd.
> >
> > Signed-off-by: Tina Zhang <tina.zhang at intel.com>
> >
> > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> > index ae46105..c92bc69 100644
> > --- a/include/uapi/linux/vfio.h
> > +++ b/include/uapi/linux/vfio.h
> > @@ -502,6 +502,36 @@ struct vfio_pci_hot_reset {
> >
> >  #define VFIO_DEVICE_PCI_HOT_RESET	_IO(VFIO_TYPE, VFIO_BASE +
> 13)
> >
> > +/**
> > + * VFIO_DEVICE_QUERY_GFX_PLANE - _IOW(VFIO_TYPE, VFIO_BASE + 14,
> > + *                           struct vfio_device_query_gfx_plane)
> > + * Return: 0 on success, -errno on failure.
> > + */
> > +
> > +struct vfio_device_gfx_plane_info {
> > +	__u64 start;
> > +	__u64 drm_format_mod;
> > +	__u32 drm_format;
> > +	__u32 width;
> > +	__u32 height;
> > +	__u32 stride;
> > +	__u32 size;
> > +	__u32 x_pos;
> > +	__u32 y_pos;
> > +};
> > +
> 
> Above structure looks good to me.
> 
> > +struct vfio_device_query_gfx_plane {
> > +	__u32 argsz;
> > +	__u32 flags;
> > +	struct vfio_device_gfx_plane_info plane_info;
> > +	__u32 plane_type;
> > +	__s32 fd; /* dma-buf fd */
> > +	__u32 plane_id;
> > +};
> > +
> 
> It would be better to have comment here about what are expected values for
> plane_type and plane_id.
I will add the comments for these fields. Thanks.

Tina
> 
> Thanks,
> Kirti
> 
> > +#define VFIO_DEVICE_QUERY_GFX_PLANE _IO(VFIO_TYPE, VFIO_BASE + 14)
> > +
> > +
> >  /* -------- API for Type1 VFIO IOMMU -------- */
> >
> >  /**
> >