tests: Include UML defconfig

Include a defconfig for building kernel as UML. Also update the README
with a few notes related to UML.

Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>

tests/hwsim/vm/README

@@ -1,9 +1,23 @@
-These scripts allow you to run the hwsim tests inside a KVM virtual machine.
+These scripts allow you to run the hwsim tests inside a KVM virtual machine or
+as a UML (User Mode Linux) program.
 
-To set it up, first compile a kernel with the kernel-config file as the
-.config. You can adjust it as needed, the configuration is for a 64-bit
-x86 system and should be close to minimal. The architecture must be the
-same as your host since the host's filesystem is used.
+To set it up, first compile a kernel with the kernel-config[.uml] file as the
+.config. You can adjust it as needed, the configuration is for a 64-bit x86
+system and should be close to minimal. The architecture must be the same as
+your host since the host's filesystem is used.
+
+To build the regular x86_64 kernel, simply issue
+
+yes "" | make -j <n_cpus>
+
+or to build UML:
+
+yes "" | ARCH=um make -j <n_cpus>
+
+Running a UML kernel is recommended as it can optimize out any sleep()s or
+kernel timers by taking advantage of UML time travel mode, greatly increasing
+test efficiency (~3200 tests can be run in under 5 minutes using parallel-vm.py
+on a 24 core CPU).
 
 Install the required tools: at least 'kvm', if you want tracing trace-cmd,
 valgrind if you want, etc.

tests/hwsim/vm/kernel-config.uml

@@ -0,0 +1,131 @@
+CONFIG_SYSVIPC=y
+CONFIG_POSIX_MQUEUE=y
+CONFIG_NO_HZ=y
+CONFIG_HIGH_RES_TIMERS=y
+CONFIG_BSD_PROCESS_ACCT=y
+CONFIG_IKCONFIG=y
+CONFIG_IKCONFIG_PROC=y
+CONFIG_LOG_BUF_SHIFT=14
+CONFIG_CGROUPS=y
+CONFIG_BLK_CGROUP=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_CGROUP_FREEZER=y
+CONFIG_CGROUP_DEVICE=y
+CONFIG_CGROUP_CPUACCT=y
+# CONFIG_PID_NS is not set
+CONFIG_SYSFS_DEPRECATED=y
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
+CONFIG_SLAB=y
+CONFIG_HOSTFS=y
+CONFIG_MAGIC_SYSRQ=y
+CONFIG_MMAPPER=y
+# CONFIG_SECCOMP is not set
+CONFIG_UML_TIME_TRAVEL_SUPPORT=y
+CONFIG_SSL=y
+CONFIG_NULL_CHAN=y
+CONFIG_PORT_CHAN=y
+CONFIG_PTY_CHAN=y
+CONFIG_TTY_CHAN=y
+CONFIG_XTERM_CHAN=y
+CONFIG_CON_CHAN="pts"
+CONFIG_SSL_CHAN="pts"
+CONFIG_UML_NET=y
+CONFIG_UML_NET_TUNTAP=y
+CONFIG_UML_NET_VECTOR=y
+# CONFIG_BLK_DEV_BSG is not set
+# CONFIG_MQ_IOSCHED_DEADLINE is not set
+# CONFIG_MQ_IOSCHED_KYBER is not set
+CONFIG_BINFMT_MISC=y
+# CONFIG_COMPACTION is not set
+CONFIG_NET=y
+CONFIG_PACKET=y
+CONFIG_UNIX=y
+CONFIG_INET=y
+CONFIG_IP_MULTICAST=y
+CONFIG_IP_ADVANCED_ROUTER=y
+CONFIG_IP_MULTIPLE_TABLES=y
+CONFIG_NETFILTER=y
+CONFIG_BRIDGE_NETFILTER=y
+CONFIG_NF_TABLES=y
+CONFIG_NETFILTER_XTABLES=y
+CONFIG_NETFILTER_XT_MATCH_PKTTYPE=y
+CONFIG_NF_TABLES_BRIDGE=y
+CONFIG_BRIDGE_NF_EBTABLES=y
+CONFIG_BRIDGE_EBT_T_FILTER=y
+CONFIG_BRIDGE_EBT_ARP=y
+CONFIG_BRIDGE_EBT_IP=y
+CONFIG_BRIDGE_EBT_IP6=y
+CONFIG_BRIDGE_EBT_PKTTYPE=y
+CONFIG_BRIDGE_EBT_ARPREPLY=y
+CONFIG_BRIDGE=y
+CONFIG_BRIDGE_VLAN_FILTERING=y
+CONFIG_VLAN_8021Q=y
+CONFIG_CFG80211=y
+CONFIG_CFG80211_DEBUGFS=y
+CONFIG_CFG80211_WEXT=y
+CONFIG_MAC80211=y
+CONFIG_MAC80211_MESH=y
+CONFIG_MAC80211_DEBUGFS=y
+CONFIG_MAC80211_MESSAGE_TRACING=y
+CONFIG_MAC80211_DEBUG_MENU=y
+CONFIG_MAC80211_VERBOSE_DEBUG=y
+CONFIG_MAC80211_MLME_DEBUG=y
+CONFIG_MAC80211_STA_DEBUG=y
+CONFIG_MAC80211_HT_DEBUG=y
+CONFIG_MAC80211_OCB_DEBUG=y
+CONFIG_MAC80211_IBSS_DEBUG=y
+CONFIG_MAC80211_PS_DEBUG=y
+CONFIG_MAC80211_TDLS_DEBUG=y
+CONFIG_MAC80211_DEBUG_COUNTERS=y
+CONFIG_RFKILL=y
+CONFIG_UEVENT_HELPER=y
+CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+CONFIG_BLK_DEV_UBD=y
+CONFIG_BLK_DEV_LOOP=y
+CONFIG_DUMMY=y
+CONFIG_MACSEC=y
+CONFIG_VETH=y
+# CONFIG_ETHERNET is not set
+# CONFIG_WLAN_VENDOR_ADMTEK is not set
+# CONFIG_WLAN_VENDOR_ATH is not set
+# CONFIG_WLAN_VENDOR_ATMEL is not set
+# CONFIG_WLAN_VENDOR_BROADCOM is not set
+# CONFIG_WLAN_VENDOR_CISCO is not set
+# CONFIG_WLAN_VENDOR_INTEL is not set
+# CONFIG_WLAN_VENDOR_INTERSIL is not set
+# CONFIG_WLAN_VENDOR_MARVELL is not set
+# CONFIG_WLAN_VENDOR_MEDIATEK is not set
+# CONFIG_WLAN_VENDOR_RALINK is not set
+# CONFIG_WLAN_VENDOR_REALTEK is not set
+# CONFIG_WLAN_VENDOR_RSI is not set
+# CONFIG_WLAN_VENDOR_ST is not set
+# CONFIG_WLAN_VENDOR_TI is not set
+# CONFIG_WLAN_VENDOR_ZYDAS is not set
+# CONFIG_WLAN_VENDOR_QUANTENNA is not set
+CONFIG_MAC80211_HWSIM=y
+CONFIG_LEGACY_PTY_COUNT=32
+# CONFIG_HW_RANDOM is not set
+CONFIG_UML_RANDOM=y
+# CONFIG_IOMMU_SUPPORT is not set
+# CONFIG_DNOTIFY is not set
+# CONFIG_INOTIFY_USER is not set
+CONFIG_PROC_KCORE=y
+CONFIG_TMPFS=y
+# CONFIG_MISC_FILESYSTEMS is not set
+# CONFIG_NETWORK_FILESYSTEMS is not set
+CONFIG_NLS=y
+CONFIG_LSM="yama,loadpin,safesetid,integrity"
+CONFIG_CRYPTO_CRC32C=y
+CONFIG_CRYPTO_ARC4=y
+CONFIG_CRC16=y
+CONFIG_PRINTK_TIME=y
+CONFIG_DEBUG_INFO=y
+CONFIG_FRAME_WARN=1024
+CONFIG_DEBUG_FS=y
+CONFIG_DEBUG_KERNEL=y
+CONFIG_PANIC_ON_OOPS=y
+CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y
+CONFIG_PREEMPTIRQ_EVENTS=y
+# CONFIG_RUNTIME_TESTING_MENU is not set