drivers/vhost/vringh.c:567:18: sparse: sparse: restricted __virtio16 degrades to integer

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   4ac6d90867a4de2e12117e755dbd76e08d88697f
commit: d877322bc1adcab9850732275670409e8bcca4c4 openrisc: Fix issue with get_user for 64-bit values
date:   12 months ago
config: openrisc-randconfig-s031-20210903 (attached as .config)
compiler: or1k-linux-gcc (GCC) 11.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-rc1-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d877322bc1adcab9850732275670409e8bcca4c4
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout d877322bc1adcab9850732275670409e8bcca4c4
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=openrisc SHELL=/bin/bash drivers/vhost/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>


sparse warnings: (new ones prefixed by >>)
   drivers/vhost/vringh.c:567:18: sparse: sparse: cast to restricted __virtio16
   drivers/vhost/vringh.c:567:18: sparse: sparse: cast to restricted __virtio16
   drivers/vhost/vringh.c:567:18: sparse: sparse: cast to restricted __virtio16
>> drivers/vhost/vringh.c:567:18: sparse: sparse: restricted __virtio16 degrades to integer
>> drivers/vhost/vringh.c:567:18: sparse: sparse: restricted __virtio16 degrades to integer
   drivers/vhost/vringh.c:567:18: sparse: sparse: cast to restricted __virtio16
   drivers/vhost/vringh.c:567:18: sparse: sparse: cast to restricted __virtio16

vim +567 drivers/vhost/vringh.c

f87d0fbb579818f Rusty Russell      2013-03-20  562  
f87d0fbb579818f Rusty Russell      2013-03-20  563  /* Userspace access helpers: in this case, addresses are really userspace. */
b9f7ac8c72894c1 Michael S. Tsirkin 2014-12-12  564  static inline int getu16_user(const struct vringh *vrh, u16 *val, const __virtio16 *p)
f87d0fbb579818f Rusty Russell      2013-03-20  565  {
b9f7ac8c72894c1 Michael S. Tsirkin 2014-12-12  566  	__virtio16 v = 0;
b9f7ac8c72894c1 Michael S. Tsirkin 2014-12-12 @567  	int rc = get_user(v, (__force __virtio16 __user *)p);
b9f7ac8c72894c1 Michael S. Tsirkin 2014-12-12  568  	*val = vringh16_to_cpu(vrh, v);
b9f7ac8c72894c1 Michael S. Tsirkin 2014-12-12  569  	return rc;
f87d0fbb579818f Rusty Russell      2013-03-20  570  }
f87d0fbb579818f Rusty Russell      2013-03-20  571  

:::::: The code at line 567 was first introduced by commit
:::::: b9f7ac8c72894c19bf258a54ecaa708df4ffbe80 vringh: update for virtio 1.0 APIs

:::::: TO: Michael S. Tsirkin <mst@xxxxxxxxxx>
:::::: CC: Michael S. Tsirkin <mst@xxxxxxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

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