Remove the vars mechanism in OSDK and polish documents

tools/qemu_args.sh

@@ -2,15 +2,19 @@
 
 # SPDX-License-Identifier: MPL-2.0
 
+# This script is used to generate QEMU arguments for OSDK.
+# The positional argument $1 is the scheme.
+# A switch "-ovmf" can be passed as an argument to enable OVMF.
+
 RAND_PORT_NUM1=$(shuf -i 1024-65535 -n 1)
 RAND_PORT_NUM2=$(shuf -i 1024-65535 -n 1)
 
-echo "Forwarded QEMU guest port: $RAND_PORT_NUM1->22; $RAND_PORT_NUM2->8080" 1>&2
+echo "[$1] Forwarded QEMU guest port: $RAND_PORT_NUM1->22; $RAND_PORT_NUM2->8080" 1>&2
 
 COMMON_QEMU_ARGS="\
     -cpu Icelake-Server,+x2apic \
-    -smp $SMP \
-    -m $MEM \
+    -smp ${SMP:-1} \
+    -m ${MEM:-2G} \
     --no-reboot \
     -nographic \
     -display none \
@@ -20,10 +24,18 @@ COMMON_QEMU_ARGS="\
     -netdev user,id=net01,hostfwd=tcp::$RAND_PORT_NUM1-:22,hostfwd=tcp::$RAND_PORT_NUM2-:8080 \
     -object filter-dump,id=filter0,netdev=net01,file=virtio-net.pcap \
     -device isa-debug-exit,iobase=0xf4,iosize=0x04 \
-    -drive if=none,format=raw,id=x0,file=$EXT2_IMG \
-    -drive if=none,format=raw,id=x1,file=$EXFAT_IMG \
+    -drive if=none,format=raw,id=x0,file=./regression/build/ext2.img \
+    -drive if=none,format=raw,id=x1,file=./regression/build/exfat.img \
 "
 
+if [ "$1" = "iommu" ]; then
+    IOMMU_DEV_EXTRA=",iommu_platform=on,ats=on"
+    IOMMU_EXTRA_ARGS="\
+        -device intel-iommu,intremap=on,device-iotlb=on \
+        -device ioh3420,id=pcie.0,chassis=1\
+    "
+fi
+
 QEMU_ARGS="\
     $COMMON_QEMU_ARGS \
     -machine q35,kernel-irqchip=split \
@@ -49,13 +61,14 @@ MICROVM_QEMU_ARGS="\
     -device virtconsole,chardev=mux \
 "
 
-if [ "$MICROVM" ]; then
+if [ "$1" = "microvm" ]; then
     QEMU_ARGS=$MICROVM_QEMU_ARGS
     echo $QEMU_ARGS
     exit 0
 fi
 
-if [ "$OVMF_PATH" ]; then
+if [ "$1" = "-ovmf" ] || [ "$2" = "-ovmf" ]; then
+    OVMF_PATH="/usr/share/OVMF"
     QEMU_ARGS="${QEMU_ARGS}\
         -drive if=pflash,format=raw,unit=0,readonly=on,file=$OVMF_PATH/OVMF_CODE.fd \
         -drive if=pflash,format=raw,unit=1,file=$OVMF_PATH/OVMF_VARS.fd \