On Wed, May 20, 2020 at 9:54 PM Hans de Goede hdegoede@redhat.com wrote:
Until this commit the mainline kernel version (this version) of the vboxguest module contained a bug where it defined VBGL_IOCTL_VMMDEV_REQUEST_BIG and VBGL_IOCTL_LOG using _IOC(_IOC_READ | _IOC_WRITE, 'V', ...) instead of _IO(V, ...) as the out of tree VirtualBox upstream version does.
Since the VirtualBox userspace bits are always built against VirtualBox upstream's headers, this means that so far the mainline kernel version of the vboxguest module has been failing these 2 ioctls with -ENOTTY. I guess that VBGL_IOCTL_VMMDEV_REQUEST_BIG is never used causing us to not hit that one and sofar the vboxguest driver has failed to actually log any log messages passed it through VBGL_IOCTL_LOG.
This commit changes the VBGL_IOCTL_VMMDEV_REQUEST_BIG and VBGL_IOCTL_LOG defines to match the out of tree VirtualBox upstream vboxguest version, while keeping compatibility with the old wrong request defines so as to not break the kernel ABI in case someone has been using the old request defines.
Fixes: f6ddd094f579 ("virt: Add vboxguest driver for Virtual Box Guest integration UAPI") Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede hdegoede@redhat.com
Indeed, this sounds like the best fix
Reviewed-by: Arnd Bergmann arnd@arndb.de