hwsim tests: Add scripts to run in a VM

Instead of running on the host, it can be useful to run in a
VM, particularly to test kernel rather than userspace changes,
so add a few scripts that allow doing so easily.

The basic idea is that the VM kernel is the same architecture
as the host kernel, so the host's root filesystem can be used
(in read-only mode) to run everything. Only a log filesystem
is mounted read-write and will get all the test output.

The kernel console output is collected to a special 'console'
file in the logs directory and kernel crashes are detected.

Signed-hostap: Johannes Berg <johannes.berg@intel.com>

tests/hwsim/vm/.gitignore

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+vm-config

tests/hwsim/vm/README

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+These scripts allow you to run the hwsim tests inside a KVM virtual machine.
+
+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.
+
+Install the required tools: at least 'kvm', if you want tracing trace-cmd,
+valgrind if you want, etc.
+
+Compile the hwsim tests as per the instructions given, you may have to
+install some extra development packages (e.g. binutils-dev for libbfd).
+
+Create a vm-config file and put the KERNELDIR option into it (see the
+vm-run.sh script). If you want valgrind, also increase the memory size.
+
+Now you can run the vm-run.sh script and it will execute the tests using
+your system's root filesystem (read-only) inside the VM. The options you
+give it are passed through to run-all.sh, see there.

tests/hwsim/vm/inside.sh

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+#!/bin/sh
+
+# mount all kinds of things
+mount tmpfs -t tmpfs /etc
+# we need our own /dev/rfkill, and don't want device access
+mount tmpfs -t tmpfs /dev
+mount tmpfs -t tmpfs /tmp
+# some sockets go into /var/run, and / is read-only
+mount tmpfs -t tmpfs /var/run
+mount proc -t proc /proc
+mount sysfs -t sysfs /sys
+# needed for tracing
+mount debugfs -t debugfs /sys/kernel/debug
+
+# reboot on any sort of crash
+sysctl kernel.panic_on_oops=1
+sysctl kernel.panic=1
+
+# get extra command line variables from /proc/cmdline
+TESTDIR=$(sed 's/.*testdir=\([^ ]*\) .*/\1/' /proc/cmdline)
+EPATH=$(sed 's/.*EPATH=\([^ ]*\) .*/\1/' /proc/cmdline)
+ARGS=$(sed 's/.*ARGS=//' /proc/cmdline)
+
+# create /dev entries we need
+mknod -m 660 /dev/ttyS0 c 4 64
+mknod -m 660 /dev/random c 1 8
+mknod -m 660 /dev/urandom c 1 9
+mknod -m 666 /dev/null c 1 3
+test -f /sys/class/misc/rfkill/dev && \
+	mknod -m 660 /dev/rfkill c $(cat /sys/class/misc/rfkill/dev | tr ':' ' ')
+ln -s /proc/self/fd/0 /dev/stdin
+ln -s /proc/self/fd/1 /dev/stdout
+ln -s /proc/self/fd/2 /dev/stderr
+
+# create dummy sudo - everything runs as uid 0
+mkdir /tmp/bin
+cat > /tmp/bin/sudo << EOF
+#!/bin/bash
+
+exec "\$@"
+EOF
+chmod +x /tmp/bin/sudo
+# and put it into $PATH, as well as our extra-$PATH
+export PATH=/tmp/bin:$EPATH:$PATH
+
+# some tests assume adm/admin group(s) exist(s)
+echo 'adm:x:0:' > /etc/group
+echo 'admin:x:0:' >> /etc/group
+# root should exist
+echo 'root:x:0:0:root:/tmp:/bin/bash' > /etc/passwd
+
+# local network is needed for some tests
+ip link set lo up
+
+# create logs mountpoint and mount the logshare
+mkdir /tmp/logs
+mount -t 9p -o trans=virtio,rw logshare /tmp/logs
+
+# check if we're rebooting due to a kernel panic ...
+if grep -q 'Kernel panic' /tmp/logs/console ; then
+	echo "KERNEL CRASHED!" >/dev/ttyS0
+else
+	# finally run the tests
+	export USER=0
+	export LOGDIR=/tmp/logs
+
+	cd $TESTDIR
+	./run-all.sh $ARGS >/dev/ttyS0 2>&1
+	#bash </dev/ttyS0 >/dev/ttyS0 2>&1
+fi
+
+# and shut down the machine again
+halt -f -p

tests/hwsim/vm/vm-run.sh

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+#!/bin/bash
+
+cd "$(dirname $0)"
+
+if [ -z "$TESTDIR" ] ; then
+	TESTDIR=$(pwd)/../
+fi
+
+LOGS=/tmp/hwsim-test-logs/
+
+# increase the memory size if you want to run with valgrind, 512 MB works
+MEMORY=128
+
+# Some ubuntu systems (notably 12.04) have issues with this - since the guest
+# mounts as read-only it should be safe to not specify ,readonly. Override in
+# vm-config if needed (see below)
+ROTAG=,readonly
+
+# set this to ttyS0 to see kvm messages (if something doesn't work)
+KVMOUT=ttyS1
+
+# you can set EPATH if you need anything extra in $PATH inside the VM
+#EPATH=/some/dir
+
+test -f vm-config && . vm-config
+
+if [ -z "$KERNELDIR" ] ; then
+	echo "You need to set a KERNELDIR (in the environment or vm-config)"
+	exit 2
+fi
+KERNEL=$KERNELDIR/arch/x86_64/boot/bzImage
+
+
+CMD=$TESTDIR/vm/inside.sh
+LOGDIR=$LOGS/$(date +%s)
+mkdir -p $LOGDIR
+
+exec kvm \
+	-kernel $KERNEL -smp 4 \
+	-s -m $MEMORY -nographic \
+	-fsdev local,security_model=none,id=fsdev-root,path=/$ROTAG \
+	-device virtio-9p-pci,id=fs-root,fsdev=fsdev-root,mount_tag=/dev/root \
+	-fsdev local,security_model=none,id=fsdev-logs,path="$LOGDIR",writeout=immediate \
+	-device virtio-9p-pci,id=fs-logs,fsdev=fsdev-logs,mount_tag=logshare \
+	-monitor null -serial stdio -serial file:$LOGDIR/console \
+	-append "mac80211_hwsim.radios=5 init=$CMD testdir=$TESTDIR console=$KVMOUT root=/dev/root rootflags=trans=virtio,version=9p2000.u ro rootfstype=9p EPATH=$EPATH ARGS=$*"