Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r267632:

Fix GCC compile warning: Variable(s) can be used uninitialized.

PR: 193076

MFC r268012, r268196:

- Remove some write only variables
- Give each interrupt a descriptive name when using MSIX

MFC r267661, r267662, r267663:

- Remove an unnecessary kick of the host at the end of transmitting
- Handle multiple calls to rxq_eof for single packet completion
- Increment the pending packets more aggressively for TSO

MFC r267252, r267253:

- Remove an unnecessary variable reassignment
- Fix TSO support on VMware Fusion

MFC svn 267065 and 267187

make sure ifp->if_transmit returns 0 if a buffer is enqueued.
This should also be merged to stable/9.

After this fix, drivers still known to have this bug are igxbe/ixv
and i40e.

Drivers using if_transmit are correct, and so are most of the
other drivers that reassing if_transmit.

Among other things, this bug causes panics when using netmap emulation
on top of generic drivers.

MFC r263259
Add Tx/Rx multiqueue support to vmx(4)

As a prerequisite for multiple queues, the guest must have MSIX enabled.
Unfortunately, to work around device passthrough bugs, FreeBSD disables
MSIX when running as a VMWare guest due to the hw.pci.honor_msi_blacklist
tunable; this tunable must be disabled for multiple queues.

Also included is various minor changes from the projects/vmxnet branch.

MFC r264865
Update the date that was missed in r263259

MFC r256308:

Do not provide a hint of the guest's OS version

The calculation can overflow if __FreeBSD_version is big
enough, and it does not appear to be required.

Approved by: re (gjb)

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Few more minor if_vmx tweaks

- Allow the Rx/Tx queue sizes to be configured by tunables
- Bail out earlier if the Tx queue unlikely has enough free
descriptors to hold the frame
- Cleanup some of the offloading capabilities handling

Couple minor if_vmx tweaks

- Use queue size fields from the Tx/Rx queues in various places
instead of (currently the same values) from the softc.
- Fix potential crash in detach if the attached failed to alloc
queue memory.
- Move the VMXNET3_MAX_RX_SEGS define to a better spot.
- Tweak frame size calculation w.r.t. ETHER_ALIGN. This could be
tweaked some more, or removed since it probably doesn't matter
much for x86 (and the x86 class of machines this driver will
be used on).

Add vmx(4), a VMware VMXNET3 ethernet driver ported from OpenBSD