On 05/02/2018 09:46 AM, Michael S. Tsirkin wrote: > 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 <vyasevic@xxxxxxxxxx> >>>> --- >>>> 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". Yes, just as TUN_F_CSUM means that tun device can handle packets with partial tcp/udp checksum. > > Now what is the implication for macvtap? The implication is exactly the same as for TUN_F_CSUM. If the flag is set on the macvtap device, the TX checksum feature is turned on. > And why are > you setting NETIF_F_SCTP_CRC which is a flag > that affects packets sent by guest to host? Mainly its because we are using just 1 flag to control checksum offloading and we need to be able control both tx and rx paths. What you are suggesting that we either invert what TUN_F_CSUM is doing in macvtap case, or have another flag that lets us control TX and RX paths separately. Either case, that would be separate work. -vlad > > >>> >>> >>>> /* 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 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
