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

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

Add svn properties to the recently merged bhyve source files.

The pre-commit hook will not allow any commits without the svn:keywords
property in head.

Merge projects/bhyve to head.

'bhyve' was developed by grehan@ and myself at NetApp (thanks!).

Special thanks to Peter Snyder, Joe Caradonna and Michael Dexter for their
support and encouragement.

Obtained from: NetApp

Probe for existence of the bvm debug port instead of just assuming that it is
always present.

Suggested by: grehan
Obtained from: NetApp

Allow the paravirtualized debug port to override others.

Obtained from: NetApp

First cut at porting the kernel portions of 221828 and 221905 from the
BHyVe reference branch to HEAD.

bhyve import part 2 of 2, guest kernel changes.
This branch is now considered frozen: future bhyve development will take
place in a branch off -CURRENT.

sys/dev/bvm/bvm_console.c
sys/dev/bvm/bvm_dbg.c
- simple console driver/gdb debug port used for bringup. supported
by user-space bhyve executable

sys/conf/options.amd64
sys/amd64/amd64/minidump_machdep.c
- allow NKPT to be set in the kernel config file

sys/amd64/conf/GENERIC
- mptable config options; bhyve user-space executable creates an mptable
with number of CPUs, and optional vendor extension
- add bvm console/debug
- set NKPT to 512 to allow loading of large RAM disks from the loader
- include kdb/gdb

sys/amd64/amd64/local_apic.c
sys/amd64/amd64/apic_vector.S
sys/amd64/include/specialreg.h
- if x2apic mode available, use MSRs to access the local APIC, otherwise
fall back to 'classic' MMIO mode

sys/amd64/amd64/mp_machdep.c
- support AP spinup on CPU models that don't have real-mode support by
overwriting the real-mode page with a message that supplies the bhyve
user-space executable with enough information to start the AP directly
in 64-bit mode.

sys/amd64/amd64/vm_machdep.c
- insert pause statements into cpu shutdown busy-wait loops

sys/dev/blackhole/blackhole.c
sys/modules/blackhole/Makefile
- boot-time loadable module that claims all PCI bus/slot/funcs specified
in an env var that are to be used for PCI passthrough

sys/amd64/amd64/intr_machdep.c
- allow round-robin assignment of device interrupts to CPUs to be disabled
from the loader

sys/amd64/include/bus.h
- convert string ins/outs instructions to loops of individual in/out since
bhyve doesn't support these yet

sys/kern/subr_bus.c
- if the device was no created with a fixed devclass, then remove it's
association with the devclass it was associated with during probe.
Otherwise, new drivers do not get a chance to probe/attach since the
device will stay married to the first driver that it probed successfully
but failed to attach.

Sponsored by: NetApp, Inc.