vfio-dev/mdpy-fb: Use fbdev I/O helpers

Set struct fb_ops and with FB_DEFAULT_IOMEM_OPS, fbdev's initializer
for I/O memory. Sets the callbacks to the cfb_ and fb_io_ functions.
Select the correct modules with Kconfig's FB_IOMEM_HELPERS token.

The macro and token set the currently selected values, so there is
no functional change.

v3:
* use _IOMEM_ in commit message
v2:
* updated to use _IOMEM_ tokens

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Helge Deller <deller@gmx.de>
Cc: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230803184034.6456-48-tzimmermann@suse.de

vfio-mdev: Remove flag FBINFO_DEFAULT from fbdev sample driver

The flag FBINFO_DEFAULT is 0 and has no effect, as struct fbinfo.flags
has been allocated to zero by framebuffer_alloc(). So do not set it.

Flags should signal differences from the default values. After cleaning
up all occurrences of FBINFO_DEFAULT, the token will be removed.

v2:
* fix commit message (Miguel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230715185343.7193-8-tzimmermann@suse.de

vfio-mdev/mdpy-fb: Do not set struct fb_info.apertures

Generic fbdev drivers use the apertures field in struct fb_info to
control ownership of the framebuffer memory and graphics device. Do
not set the values in mdpy-fb.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221219160516.23436-10-tzimmermann@suse.de

samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe()

Add missing pci_disable_device() in fail path of mdpy_fb_probe().
Besides, fix missing release functions in mdpy_fb_remove().

Fixes: cacade1946a4 ("sample: vfio mdev display - guest driver")
Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com>
Link: https://lore.kernel.org/r/20221208013341.3999-1-shangxiaojing@huawei.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

samples: vfio-mdev: fix error handing in mdpy_fb_probe()

Fix to return a negative error code from the framebuffer_alloc() error
handling case instead of 0, also release regions in some error handing
cases.

Fixes: cacade1946a4 ("sample: vfio mdev display - guest driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Message-Id: <20210520133641.1421378-1-weiyongjun1@huawei.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

samples: vfio-mdev: constify fb ops

Now that the fbops member of struct fb_info is const, we can start
making the ops const as well.

v2: fix typo (Christophe de Dinechin)

Cc: Kirti Wankhede <kwankhede@nvidia.com>
Cc: kvm@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ddb10df1316ef585930cda7718643a580f4fe37b.1575390741.git.jani.nikula@intel.com

sample: vfio mdev display - guest driver

Guest fbdev driver for CONFIG_SAMPLE_VFIO_MDEV_MDPY.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>