MFC 266125:
Implement a PCI interrupt router to route PCI legacy INTx interrupts to
the legacy 8259A PICs.

MFC 260206:
Rework the DSDT generation code a bit to generate more accurate info about
LPC devices. Among other things, the LPC serial ports now appear as
ACPI devices.

MFC 259826,259997,259998:
Support soft power-off via the ACPI S5 state for bhyve guests and wire
up a virtual power button to SIGTERM:
- Implement the PM1_EVT and PM1_CTL registers required by ACPI.
- Emulate the Reset Control register at I/O port 0xcf9.
- Advertise an _S5 package.
- Implement an SMI_CMD register with commands to enable and disable ACPI.
Currently the only change when ACPI is enabled is to enable the virtual
power button via SIGTERM.
- Implement a fixed-feature power button when ACPI is enabled by asserting
PWRBTN_STS in PM1_EVT when SIGTERM is received.
- Add support for EVFILT_SIGNAL events to mevent.
- Implement support for the ACPI system command interrupt (SCI) and assert
it when needed based on the values in PM1_EVT. Mark the SCI as active-low
and level triggered in the MADT and MP Table.

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 266125:
Implement a PCI interrupt router to route PCI legacy INTx interrupts to
the legacy 8259A PICs.

MFC 260206:
Rework the DSDT generation code a bit to generate more accurate info about
LPC devices. Among other things, the LPC serial ports now appear as
ACPI devices.

MFC 259826,259997,259998:
Support soft power-off via the ACPI S5 state for bhyve guests and wire
up a virtual power button to SIGTERM:
- Implement the PM1_EVT and PM1_CTL registers required by ACPI.
- Emulate the Reset Control register at I/O port 0xcf9.
- Advertise an _S5 package.
- Implement an SMI_CMD register with commands to enable and disable ACPI.
Currently the only change when ACPI is enabled is to enable the virtual
power button via SIGTERM.
- Implement a fixed-feature power button when ACPI is enabled by asserting
PWRBTN_STS in PM1_EVT when SIGTERM is received.
- Add support for EVFILT_SIGNAL events to mevent.
- Implement support for the ACPI system command interrupt (SCI) and assert
it when needed based on the values in PM1_EVT. Mark the SCI as active-low
and level triggered in the MADT and MP Table.

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