hyperv/hn: Trust host TCP segment checksum verification by default

[sepherosa_gmail.com]

Summary

According to all available information, VMSWITCH always does the
TCP segment checksum verification before send the segment to guest.

[delphij]

I think the change is Okay but would suggest that this be documented as a CTLFLAG_RDTUN sysctl so it's easier for users to figure out what they means (and their present value).

[sepherosa_gmail.com]

In D4991#105751, @delphij wrote:

I think the change is Okay but would suggest that this be documented as a CTLFLAG_RDTUN sysctl so it's easier for users to figure out what they means (and their present value).

Heh, the sysctl for this tunable was in the devclass sysctl tree, they are just added dynamically, since the devclass sysctl tree is created dynamiclly. On this hyperv (I used to write this reply down :):

fbsd-cur-sephe:netvsc# sysctl dev.hn
dev.hn.tso_maxlen: 0
dev.hn.tx_chimney_size: 0
dev.hn.trust_hosttcp: 1

[delphij]

In D4991#105759, @sepherosa_gmail.com wrote:

In D4991#105751, @delphij wrote:

I think the change is Okay but would suggest that this be documented as a CTLFLAG_RDTUN sysctl so it's easier for users to figure out what they means (and their present value).

Heh, the sysctl for this tunable was in the devclass sysctl tree, they are just added dynamically, since the devclass sysctl tree is created dynamiclly. On this hyperv (I used to write this reply down :):

fbsd-cur-sephe:netvsc# sysctl dev.hn
dev.hn.tso_maxlen: 0
dev.hn.tx_chimney_size: 0
dev.hn.trust_hosttcp: 1

I see, thanks for the explanation.

[honzhan_microsoft.com]

It looks ok to me.