On Wed, May 02, 2018 at 09:27:00AM -0400, Vlad Yasevich wrote: > On 05/01/2018 11:24 PM, Michael S. Tsirkin wrote: > > On Tue, May 01, 2018 at 10:07:38PM -0400, Vladislav Yasevich wrote: > >> Since we now have support for software CRC32c offload, turn it on > >> for macvlan and macvtap devices so that guests can take advantage > >> of offload SCTP checksums to the host or host hardware. > >> > >> Signed-off-by: Vladislav Yasevich <vyase...@redhat.com> > >> --- > >> drivers/net/macvlan.c | 5 +++-- > >> drivers/net/tap.c | 8 +++++--- > >> 2 files changed, 8 insertions(+), 5 deletions(-) > >> > >> diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c > >> index 725f4b4..646b730 100644 > >> --- a/drivers/net/macvlan.c > >> +++ b/drivers/net/macvlan.c > >> @@ -834,7 +834,7 @@ static struct lock_class_key > >> macvlan_netdev_addr_lock_key; > >> > >> #define ALWAYS_ON_OFFLOADS \ > >> (NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE | \ > >> - NETIF_F_GSO_ROBUST | NETIF_F_GSO_ENCAP_ALL) > >> + NETIF_F_GSO_ROBUST | NETIF_F_GSO_ENCAP_ALL | NETIF_F_SCTP_CRC) > >> > >> #define ALWAYS_ON_FEATURES (ALWAYS_ON_OFFLOADS | NETIF_F_LLTX) > >> > >> @@ -842,7 +842,8 @@ static struct lock_class_key > >> macvlan_netdev_addr_lock_key; > >> (NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_FRAGLIST | \ > >> NETIF_F_GSO | NETIF_F_TSO | NETIF_F_LRO | \ > >> NETIF_F_TSO_ECN | NETIF_F_TSO6 | NETIF_F_GRO | NETIF_F_RXCSUM | \ > >> - NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_HW_VLAN_STAG_FILTER) > >> + NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_HW_VLAN_STAG_FILTER | \ > >> + NETIF_F_SCTP_CRC) > >> > >> #define MACVLAN_STATE_MASK \ > >> ((1<<__LINK_STATE_NOCARRIER) | (1<<__LINK_STATE_DORMANT)) > >> diff --git a/drivers/net/tap.c b/drivers/net/tap.c > >> index 9b6cb78..2c8512b 100644 > >> --- a/drivers/net/tap.c > >> +++ b/drivers/net/tap.c > >> @@ -369,8 +369,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff > >> **pskb) > >> * check, we either support them all or none. > >> */ > >> if (skb->ip_summed == CHECKSUM_PARTIAL && > >> - !(features & NETIF_F_CSUM_MASK) && > >> - skb_checksum_help(skb)) > >> + skb_csum_hwoffload_help(skb, features)) > >> goto drop; > >> if (ptr_ring_produce(&q->ring, skb)) > >> goto drop; > >> @@ -945,6 +944,9 @@ static int set_offload(struct tap_queue *q, unsigned > >> long arg) > >> } > >> } > >> > >> + if (arg & TUN_F_SCTP_CSUM) > >> + feature_mask |= NETIF_F_SCTP_CRC; > >> + > > > > so this still affects TX, shouldn't this affect RX instead? > > There is no bit to set on the RX path just like there is no bit to set on the > RX patch > for TUN_F_CSUM. > > We only invert TSO offloads, not checksum offloads as the comment below > states. > For checksum, macvtap has to compute the checksum itself in > tap_handle_frame() above. > It uses tx feature bits to see if needs do to the checksum. > > If you think we need another flag to macvtap to control RXCSUM, that would > need to be > separate and cover standard TCP checksum as well. > > -vlad
Confused. What is the meaning of TUN_F_SCTP_CSUM? I assume this is a way for userspace to tell tun device: "I can handle packets without SCTP checksum, pls send them my way". Now what is the implication for macvtap? And why are you setting NETIF_F_SCTP_CRC which is a flag that affects packets sent by guest to host? > > > > > >> /* tun/tap driver inverts the usage for TSO offloads, where > >> * setting the TSO bit means that the userspace wants to > >> * accept TSO frames and turning it off means that user space > >> @@ -1077,7 +1079,7 @@ static long tap_ioctl(struct file *file, unsigned > >> int cmd, > >> case TUNSETOFFLOAD: > >> /* let the user check for future flags */ > >> if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | > >> - TUN_F_TSO_ECN | TUN_F_UFO)) > >> + TUN_F_TSO_ECN | TUN_F_UFO | TUN_F_SCTP_CSUM)) > >> return -EINVAL; > >> > >> rtnl_lock(); > >> -- > >> 2.9.5
