Re: [PATCH net-next 8/8] vhost/net: enable gso over UDP tunnel support.

[kernel test robot <lkp@intel.com>]

Hi Paolo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Paolo-Abeni/virtio-introduce-virtio_features_t/20250521-183700
base:   net-next/main
patch link:    https://lore.kernel.org/r/f95716aed2c65d079cdb10518431088f3e103899.1747822866.git.pabeni%40redhat.com
patch subject: [PATCH net-next 8/8] vhost/net: enable gso over UDP tunnel support.
config: i386-buildonly-randconfig-001-20250522 (https://download.01.org/0day-ci/archive/20250522/202505221428.67HNn025-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250522/202505221428.67HNn025-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505221428.67HNn025-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/vhost/net.c:1633:30: warning: shift count >= width of type [-Wshift-count-overflow]
    1633 |         has_tunnel = !!(features & (VIRTIO_BIT(VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO) |
         |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/virtio_features.h:18:24: note: expanded from macro 'VIRTIO_BIT'
      18 | #define VIRTIO_BIT(b)           BIT_ULL(b)
         |                                 ^~~~~~~~~~
   include/vdso/bits.h:8:30: note: expanded from macro 'BIT_ULL'
       8 | #define BIT_ULL(nr)             (ULL(1) << (nr))
         |                                         ^  ~~~~
   drivers/vhost/net.c:1634:9: warning: shift count >= width of type [-Wshift-count-overflow]
    1634 |                                     VIRTIO_BIT(VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO)));
         |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/virtio_features.h:18:24: note: expanded from macro 'VIRTIO_BIT'
      18 | #define VIRTIO_BIT(b)           BIT_ULL(b)
         |                                 ^~~~~~~~~~
   include/vdso/bits.h:8:30: note: expanded from macro 'BIT_ULL'
       8 | #define BIT_ULL(nr)             (ULL(1) << (nr))
         |                                         ^  ~~~~
   2 warnings generated.


vim +1633 drivers/vhost/net.c

  1622	
  1623	static int vhost_net_set_features(struct vhost_net *n, virtio_features_t features)
  1624	{
  1625		size_t vhost_hlen, sock_hlen, hdr_len;
  1626		bool has_tunnel;
  1627		int i;
  1628	
  1629		hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
  1630				       (1ULL << VIRTIO_F_VERSION_1))) ?
  1631				sizeof(struct virtio_net_hdr_mrg_rxbuf) :
  1632				sizeof(struct virtio_net_hdr);
> 1633		has_tunnel = !!(features & (VIRTIO_BIT(VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO) |
  1634					    VIRTIO_BIT(VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO)));
  1635		hdr_len += has_tunnel ? sizeof(struct virtio_net_hdr_tunnel) : 0;
  1636		if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
  1637			/* vhost provides vnet_hdr */
  1638			vhost_hlen = hdr_len;
  1639			sock_hlen = 0;
  1640		} else {
  1641			/* socket provides vnet_hdr */
  1642			vhost_hlen = 0;
  1643			sock_hlen = hdr_len;
  1644		}
  1645		mutex_lock(&n->dev.mutex);
  1646		if ((features & (1 << VHOST_F_LOG_ALL)) &&
  1647		    !vhost_log_access_ok(&n->dev))
  1648			goto out_unlock;
  1649	
  1650		if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {
  1651			if (vhost_init_device_iotlb(&n->dev))
  1652				goto out_unlock;
  1653		}
  1654	
  1655		for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
  1656			mutex_lock(&n->vqs[i].vq.mutex);
  1657			n->vqs[i].vq.acked_features = features;
  1658			n->vqs[i].vhost_hlen = vhost_hlen;
  1659			n->vqs[i].sock_hlen = sock_hlen;
  1660			mutex_unlock(&n->vqs[i].vq.mutex);
  1661		}
  1662		mutex_unlock(&n->dev.mutex);
  1663		return 0;
  1664	
  1665	out_unlock:
  1666		mutex_unlock(&n->dev.mutex);
  1667		return -EFAULT;
  1668	}
  1669	

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