#
# FIRECRACKER -- kernel configuration file for Firecracker VM
#
# This is largely a stripped-down version of the GENERIC kernel configuration
# file, without drivers for hardware which will never appear inside the
# Firecracker VM environment.  It adds support for the Virtio MMIO bus,
# which Firecracker uses for exposing devices, and legacy mptable, which
# Firecracker uses for exposing information about CPUs (since it doesn't
# support ACPI).
#
# Since Firecracker loads the kernel directly via the PVH boot protocol,
# it bypasses the boot loader; some environment variables are hard-coded
# here which would normally be provided via device hints or loader.conf.
#
# For more information about the Firecracker VM, see:
#
#    https://firecracker-microvm.github.io/

cpu		HAMMER
ident		FIRECRACKER

makeoptions	DEBUG=-g		# Build kernel with gdb(1) debug symbols
makeoptions	WITH_CTF=1		# Run ctfconvert(1) for DTrace support

options 	SCHED_ULE		# ULE scheduler
options 	NUMA			# Non-Uniform Memory Architecture support
options 	PREEMPTION		# Enable kernel thread preemption
options 	VIMAGE			# Subsystem virtualization, e.g. VNET
options 	INET			# InterNETworking
options 	INET6			# IPv6 communications protocols
options 	IPSEC_SUPPORT		# Allow kldload of ipsec and tcpmd5
options 	ROUTE_MPATH		# Multipath routing support
options 	FIB_ALGO		# Modular fib lookups
options 	TCP_OFFLOAD		# TCP offload
options 	TCP_BLACKBOX		# Enhanced TCP event logging
options 	TCP_HHOOK		# hhook(9) framework for TCP
options 	TCP_RFC7413		# TCP Fast Open
options 	SCTP_SUPPORT		# Allow kldload of SCTP
options 	KERN_TLS		# TLS transmit & receive offload
options 	FFS			# Berkeley Fast Filesystem
options 	SOFTUPDATES		# Enable FFS soft updates support
options 	UFS_ACL			# Support for access control lists
options 	UFS_DIRHASH		# Improve performance on big directories
options 	UFS_GJOURNAL		# Enable gjournal-based UFS journaling
options 	QUOTA			# Enable disk quotas for UFS
options 	MD_ROOT			# MD is a potential root device
options 	NFSCL			# Network Filesystem Client
options 	NFSD			# Network Filesystem Server
options 	NFSLOCKD		# Network Lock Manager
options 	NFS_ROOT		# NFS usable as /, requires NFSCL
options 	MSDOSFS			# MSDOS Filesystem
options 	CD9660			# ISO 9660 Filesystem
options 	PROCFS			# Process filesystem (requires PSEUDOFS)
options 	PSEUDOFS		# Pseudo-filesystem framework
options 	TMPFS			# Efficient memory filesystem
options 	GEOM_RAID		# Soft RAID functionality.
options 	GEOM_LABEL		# Provides labelization
options 	EFIRT			# EFI Runtime Services support
options 	COMPAT_FREEBSD32	# Compatible with i386 binaries
options 	COMPAT_FREEBSD4		# Compatible with FreeBSD4
options 	COMPAT_FREEBSD5		# Compatible with FreeBSD5
options 	COMPAT_FREEBSD6		# Compatible with FreeBSD6
options 	COMPAT_FREEBSD7		# Compatible with FreeBSD7
options 	COMPAT_FREEBSD9		# Compatible with FreeBSD9
options 	COMPAT_FREEBSD10	# Compatible with FreeBSD10
options 	COMPAT_FREEBSD11	# Compatible with FreeBSD11
options 	COMPAT_FREEBSD12	# Compatible with FreeBSD12
options 	COMPAT_FREEBSD13	# Compatible with FreeBSD13
options 	SCSI_DELAY=5000		# Delay (in ms) before probing SCSI
options 	KTRACE			# ktrace(1) support
options 	STACK			# stack(9) support
options 	SYSVSHM			# SYSV-style shared memory
options 	SYSVMSG			# SYSV-style message queues
options 	SYSVSEM			# SYSV-style semaphores
options 	_KPOSIX_PRIORITY_SCHEDULING # POSIX P1003_1B real-time extensions
options 	PRINTF_BUFR_SIZE=128	# Prevent printf output being interspersed.
options 	KBD_INSTALL_CDEV	# install a CDEV entry in /dev
options 	HWPMC_HOOKS		# Necessary kernel hooks for hwpmc(4)
options 	AUDIT			# Security event auditing
options 	CAPABILITY_MODE		# Capsicum capability mode
options 	CAPABILITIES		# Capsicum capabilities
options 	MAC			# TrustedBSD MAC Framework
options 	KDTRACE_FRAME		# Ensure frames are compiled in
options 	KDTRACE_HOOKS		# Kernel DTrace hooks
options 	DDB_CTF			# Kernel ELF linker loads CTF data
options 	INCLUDE_CONFIG_FILE	# Include this file in kernel
options 	RACCT			# Resource accounting framework
options 	RACCT_DEFAULT_TO_DISABLED # Set kern.racct.enable=0 by default
options 	RCTL			# Resource limits

# Debugging support.  Always need this:
options 	KDB			# Enable kernel debugger support.
options 	KDB_TRACE		# Print a stack trace for a panic.
# For full debugger support use (turn off in stable branch):
options 	BUF_TRACKING		# Track buffer history
options 	DDB			# Support DDB.
options 	FULL_BUF_TRACKING	# Track more buffer history
options 	GDB			# Support remote GDB.
options 	DEADLKRES		# Enable the deadlock resolver
options 	INVARIANTS		# Enable calls of extra sanity checking
options 	INVARIANT_SUPPORT	# Extra sanity checks of internal structures, required by INVARIANTS
options 	QUEUE_MACRO_DEBUG_TRASH	# Trash queue(2) internal pointers on invalidation
options 	WITNESS			# Enable checks to detect deadlocks and cycles
options 	WITNESS_SKIPSPIN	# Don't run witness on spinlocks for speed
options 	MALLOC_DEBUG_MAXZONES=8	# Separate malloc(9) zones
options 	VERBOSE_SYSINIT=0	# Support debug.verbose_sysinit, off by default

# Kernel dump features.
options 	EKCD			# Support for encrypted kernel dumps
options 	GZIO			# gzip-compressed kernel and user dumps
options 	ZSTDIO			# zstd-compressed kernel and user dumps
options 	DEBUGNET		# debugnet networking
options 	NETDUMP			# netdump(4) client support
options 	NETGDB			# netgdb(4) client support

# Make an SMP-capable kernel by default
options 	SMP			# Symmetric MultiProcessor Kernel
options 	EARLY_AP_STARTUP

# Pseudo devices.
device		crypto			# core crypto support
device		aesni			# AES-NI OpenCrypto module
device		loop			# Network loopback
device		rdrand_rng		# Intel Bull Mountain RNG
device		ether			# Ethernet support
device		vlan			# 802.1Q VLAN support
device		tuntap			# Packet tunnel.
device		md			# Memory "disks"
device		gif			# IPv6 and IPv4 tunneling
device		firmware		# firmware assist module
device		xz			# lzma decompression
device		bpf			# Berkeley packet filter

# Serial (COM) ports
device		uart			# Generic UART driver

# VirtIO support
device		virtio			# Generic VirtIO bus (required)
device		virtio_mmio		# VirtIO MMIO bus
device		vtnet			# VirtIO Ethernet device
device		virtio_blk		# VirtIO Block device

# Linux KVM paravirtualization support
device		kvm_clock		# KVM paravirtual clock driver

# Netmap provides direct access to TX/RX rings on supported NICs
device		netmap			# netmap(4) support

# Firecracker exposes information via the legacy MP Table mechanism
# rather than via ACPI (which it does not implement).
device		mptable

# Firecracker launches the FreeBSD kernel directly, via the PVH boot
# protocol, rather than via the boot loader; as such, we need to bake
# device hints into the kernel configuration rather than relying on
# device.hints being loaded, and likewise have no loader.conf to place
# other settings into.
envvar	hint.uart.0.at="isa"
envvar	hint.uart.0.port="0x3F8"
envvar	hint.uart.0.flags="0x10"
envvar	hint.uart.0.irq="0x4"
envvar	hint.acpi.0.disabled="1"

# Inside a VM, "power off" doesn't really yank the AC power, so there's
# no need to worry about disks flushing caches before losing power.
envvar	kern.shutdown.poweroff_delay="0"

# Firecracker seems to have a bug in its UART emulation.  This works
# around the problem.
envvar	hw.broken_txfifo="1"

# We don't have an early timecounter to calibrate the TSC against, so
# skip that; later in the boot process we have other timecounters.
envvar	machdep.disable_tsc_calibration="1"

# Provide bug-for-bug compatiblity with Linux in MP Table searching
# and parsing.  Firecracker relies on these bugs.
options 	MPTABLE_LINUX_BUG_COMPAT

# Disable the automatic registration of a PCI bridge; we do in fact
# not have one.
options 	NO_LEGACY_PCIB

# Bus support.
# Note that Firecracker provides neither ACPI nor PCI; but removing these
# devices currently (2022-07-09) prevents the kernel from building.
device		acpi
device		pci

# Xen HVM Guest Optimizations
# NOTE: XENHVM depends on xenpci and xentimer.
# They must be added or removed together.
# NOTE: These are present in FIRECRACKER because the PVH boot method
# originates from Xen; once that code is untangled these can be removed.
options 	XENHVM			# Xen HVM kernel infrastructure
device		xenpci			# Xen HVM Hypervisor services driver
device		xentimer		# Xen x86 PV timer device