MFC r284539, r284630, r284688, r284877, r285217, r285218,
r286837, r286838, r288470, r288522, r288524, r288826,
r289001

Pull in bhyve bug fixes and changes to allow UEFI booting.
This provides Windows support.

Tested on Intel and AMD with:
- Arch Linux i386+amd64 (kernel 4.3.3)
- Ubuntu 15.10 server 64-bit
- FreeBSD-CURRENT/amd64 20160127 snap
- FreeBSD 10.2 i386+amd64
- OpenBSD 5.8 i386+amd64
- SmartOS latest
- Windows 10 build 1511'

Huge thanks to Yamagi Burmeister who submitted the patch
and did the majority of the testing.

r284539 - bootrom mem allocation support
r284630 - Add SO_REUSEADDR when starting debug port
r284688 - Fix a regression in "movs" emulation
r284877 - verify_gla() non-zero segment base fix
r285217 - Always assert DCD and DSR in the uart
r285218 - devmem nodes moved to /dev/vmm.io/
r286837 - Add define for SATA Check-Power-Mode
r286838 - Add simple (no-op) SATA cmd emulations
r288470 - Increase virtio-blk indirect descs
r288522 - Firmware guest query interface
r288524 - Fix post-test typo
r288826 - Clean up SATA unimplemented cmd msg
r289001 - Add -l option to specify userboot path

Submitted by: Yamagi Burmeister
Approved by: re (kib)

MFC 264353,264509,264768,264770,264825,264846,264988,265114,265165,265365,
265941,265951,266390,266550,266910:
Various bhyve fixes:
- Don't save host's return address in 'struct vmxctx'.
- Permit non-32-bit accesses to local APIC registers.
- Factor out common ioport handler code.
- Use calloc() in favor of malloc + memset.
- Change the vlapic timer frequency to be in the ballpark of contemporary
hardware.
- Allow the guest to read the TSC via MSR 0x10.
- A VMCS is always inactive when it exits the vmx_run() loop. Remove
redundant code and the misleading comment that suggest otherwise.
- Ignore writes to microcode update MSR. This MSR is accessed by RHEL7
guest.
Add KTR tracepoints to annotate wrmsr and rdmsr VM exits.
- Provide an alias for the userboot console and name it 'comconsole'.
- Use EV_ADD to create an mevent and EV_ENABLE to enable it.
- abort(3) the process in response to a VMEXIT_ABORT.
- Don't include the guest memory segments in the bhyve(8) process core dump.
- Make the vmx asm code dtrace-fbt-friendly.
- Allow vmx_getdesc() and vmx_setdesc() to be called for a vcpu that is in
the VCPU_RUNNING state.
- Enable VMX in the IA32_FEATURE_CONTROL MSR if it not enabled and the MSR
isn't locked.

MFC 262884,263236,265407:
Various uart fixes:
- Open the uart emulation's backing tty in non-blocking mode.
- Support 16-bit register access.
- Disable the 'uart_drain()' callback when the emulated receive FIFO
is full.

MFC r256657,r257018,r257347,r257423,r257729,r257767,
r257933,r258609,r258614,r258668,r258673,r258855

Pull in some minor bugfixes and functionality enhancements
from CURRENT. These are candidates to be moved to 10.0-release.

r258855
mdoc: quote string properly.

r258673
Don't create an initial value for the host filesystem of "/".

r258668
Allow bhyve and bhyveload to attach to tty devices.

r258614
The 22-bit Data Byte Count (DBC) field of a Physical Region Descriptor was
being read as a 32-bit quantity by the bhyve AHCI driver.

r258609
Fix discrepancy between the IOAPIC ID advertised by firmware tables and the
actual value read by the guest.

r257933
Route the legacy timer interrupt (IRQ0) to pin 2 of the IOAPIC.

r257767
Fix an off-by-one error when iterating over the emulated PCI BARs.

r257729
Add the VM name to the process name with setproctitle().

r257423
Make the virtual ioapic available unconditionally in a bhyve virtual machine.

r257347
Update copyright to include the author of the LPC bridge emulation code.

hand-merge r257018
Tidy usage messages for bhyve and bhyveload.

r256657
Add an option to bhyveload(8) that allows setting a loader environment variable
from the command line.

Discussed with: neel

MFC r257293.

Add support for PCI-to-ISA LPC bridge emulation. If the LPC bus is attached
to a virtual machine then we implicitly create COM1 and COM2 ISA devices.

Prior to this change the only way of attaching a COM port to the virtual
machine was by presenting it as a PCI device that is mapped at the legacy
I/O address 0x3F8 or 0x2F8.

There were some issues with the original approach:
- It did not work at all with UEFI because UEFI will reprogram the PCI device
BARs and remap the COM1/COM2 ports at non-legacy addresses.
- OpenBSD GENERIC kernel does not create a /dev/console because it expects
the uart device at the legacy 0x3F8/0x2F8 address to be an ISA device.
- It was functional with a FreeBSD guest but caused the console to appear
on /dev/ttyu2 which was not intuitive.

The uart emulation is now independent of the bus on which it resides. Thus it
is possible to have uart devices on the PCI bus in addition to the legacy
COM1/COM2 devices behind the LPC bus.

The command line option to attach ISA COM1/COM2 ports to a virtual machine is
"-s <bus>,lpc -l com1,stdio".

The command line option to create a PCI-attached uart device is:
"-s <bus>,uart[,stdio]"

The command line option to create PCI-attached COM1/COM2 device is:
"-S <bus>,uart[,stdio]". This style of creating COM ports is deprecated.

Approved by: re (glebius)

MFC 264353,264509,264768,264770,264825,264846,264988,265114,265165,265365,
265941,265951,266390,266550,266910:
Various bhyve fixes:
- Don't save host's return address in 'struct vmxctx'.
- Permit non-32-bit accesses to local APIC registers.
- Factor out common ioport handler code.
- Use calloc() in favor of malloc + memset.
- Change the vlapic timer frequency to be in the ballpark of contemporary
hardware.
- Allow the guest to read the TSC via MSR 0x10.
- A VMCS is always inactive when it exits the vmx_run() loop. Remove
redundant code and the misleading comment that suggest otherwise.
- Ignore writes to microcode update MSR. This MSR is accessed by RHEL7
guest.
Add KTR tracepoints to annotate wrmsr and rdmsr VM exits.
- Provide an alias for the userboot console and name it 'comconsole'.
- Use EV_ADD to create an mevent and EV_ENABLE to enable it.
- abort(3) the process in response to a VMEXIT_ABORT.
- Don't include the guest memory segments in the bhyve(8) process core dump.
- Make the vmx asm code dtrace-fbt-friendly.
- Allow vmx_getdesc() and vmx_setdesc() to be called for a vcpu that is in
the VCPU_RUNNING state.
- Enable VMX in the IA32_FEATURE_CONTROL MSR if it not enabled and the MSR
isn't locked.

MFC 262884,263236,265407:
Various uart fixes:
- Open the uart emulation's backing tty in non-blocking mode.
- Support 16-bit register access.
- Disable the 'uart_drain()' callback when the emulated receive FIFO
is full.

MFC r256657,r257018,r257347,r257423,r257729,r257767,
r257933,r258609,r258614,r258668,r258673,r258855

Pull in some minor bugfixes and functionality enhancements
from CURRENT. These are candidates to be moved to 10.0-release.

r258855
mdoc: quote string properly.

r258673
Don't create an initial value for the host filesystem of "/".

r258668
Allow bhyve and bhyveload to attach to tty devices.

r258614
The 22-bit Data Byte Count (DBC) field of a Physical Region Descriptor was
being read as a 32-bit quantity by the bhyve AHCI driver.

r258609
Fix discrepancy between the IOAPIC ID advertised by firmware tables and the
actual value read by the guest.

r257933
Route the legacy timer interrupt (IRQ0) to pin 2 of the IOAPIC.

r257767
Fix an off-by-one error when iterating over the emulated PCI BARs.

r257729
Add the VM name to the process name with setproctitle().

r257423
Make the virtual ioapic available unconditionally in a bhyve virtual machine.

r257347
Update copyright to include the author of the LPC bridge emulation code.

hand-merge r257018
Tidy usage messages for bhyve and bhyveload.

r256657
Add an option to bhyveload(8) that allows setting a loader environment variable
from the command line.

Discussed with: neel

MFC r257293.

Add support for PCI-to-ISA LPC bridge emulation. If the LPC bus is attached
to a virtual machine then we implicitly create COM1 and COM2 ISA devices.

Prior to this change the only way of attaching a COM port to the virtual
machine was by presenting it as a PCI device that is mapped at the legacy
I/O address 0x3F8 or 0x2F8.

There were some issues with the original approach:
- It did not work at all with UEFI because UEFI will reprogram the PCI device
BARs and remap the COM1/COM2 ports at non-legacy addresses.
- OpenBSD GENERIC kernel does not create a /dev/console because it expects
the uart device at the legacy 0x3F8/0x2F8 address to be an ISA device.
- It was functional with a FreeBSD guest but caused the console to appear
on /dev/ttyu2 which was not intuitive.

The uart emulation is now independent of the bus on which it resides. Thus it
is possible to have uart devices on the PCI bus in addition to the legacy
COM1/COM2 devices behind the LPC bus.

The command line option to attach ISA COM1/COM2 ports to a virtual machine is
"-s <bus>,lpc -l com1,stdio".

The command line option to create a PCI-attached uart device is:
"-s <bus>,uart[,stdio]"

The command line option to create PCI-attached COM1/COM2 device is:
"-S <bus>,uart[,stdio]". This style of creating COM ports is deprecated.

Approved by: re (glebius)