[PATCH v5 0/8] xen: dma-buf support for grant device

[Oleksandr Andrushchenko]

On 07/20/2018 05:08 PM, Boris Ostrovsky wrote:
> On 07/20/2018 05:01 AM, Oleksandr Andrushchenko wrote:
>> From: Oleksandr Andrushchenko <oleksandr_andrushchenko at epam.com>
>>
>> This work is in response to my previous attempt to introduce Xen/DRM
>> zero-copy driver [1] to enable Linux dma-buf API [2] for Xen based
>> frontends/backends. There is also an existing hyper_dmabuf approach
>> available [3] which, if reworked to utilize the proposed solution,
>> can greatly benefit as well.
>
> Lot of warnings on  i386 build:
>
> In file included from
> /data/upstream/linux-xen/drivers/gpu/drm/xen/xen_drm_front.c:24:
> /data/upstream/linux-xen/drivers/gpu/drm/xen/xen_drm_front.h: In
> function ‘xen_drm_front_fb_to_cookie’:
> /data/upstream/linux-xen/drivers/gpu/drm/xen/xen_drm_front.h:129:9:
> warning: cast from pointer to integer of different size
> [-Wpointer-to-int-cast]
>    return (u64)fb;
>           ^
> /data/upstream/linux-xen/drivers/gpu/drm/xen/xen_drm_front.h: In
> function ‘xen_drm_front_dbuf_to_cookie’:
> /data/upstream/linux-xen/drivers/gpu/drm/xen/xen_drm_front.h:134:9:
> warning: cast from pointer to integer of different size
> [-Wpointer-to-int-cast]
>    return (u64)gem_obj;
>           ^
>    CC [M]  net/netfilter/ipset/ip_set_hash_ipport.o
>    CC      drivers/media/rc/keymaps/rc-tango.o
>    CC [M]  drivers/gpu/drm/vmwgfx/vmwgfx_fifo.o
>    AR      drivers/misc/built-in.a
> In file included from
> /data/upstream/linux-xen/drivers/gpu/drm/xen/xen_drm_front_kms.c:20:
> /data/upstream/linux-xen/drivers/gpu/drm/xen/xen_drm_front.h: In
> function ‘xen_drm_front_fb_to_cookie’:
>    CC [M]  drivers/gpu/drm/xen/xen_drm_front_conn.o
> /data/upstream/linux-xen/drivers/gpu/drm/xen/xen_drm_front.h:129:9:
> warning: cast from pointer to integer of different size
> [-Wpointer-to-int-cast]
>    return (u64)fb;
> (and more)
>
The above warnings already have a fix [1] which is expected in 4.19
>
> and then
>
> data/upstream/linux-xen/drivers/xen/gntdev-dmabuf.c: In function
> ‘gntdev_ioctl_dmabuf_exp_from_refs’:
> /data/upstream/linux-xen/drivers/xen/gntdev-dmabuf.c:503:6: warning:
> ‘args.fd’ may be used uninitialized in this function [-Wmaybe-uninitialized]
>    *fd = args.fd;
>    ~~~~^~~~~~~~~
> /data/upstream/linux-xen/drivers/xen/gntdev-dmabuf.c:467:35: note:
> ‘args.fd’ was declared here
>    struct gntdev_dmabuf_export_args args;
>                                     ^~~~
Strangely, but my i386 build goes smooth.
Which version of gcc you use and could you please give me your
.config, so I can test the same?
>
> -boris
Thank you,
Oleksandr

[1] 
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=9eece5d9c6e0316f17091e37ff3ec87331bdedf3