[kvm-unit-tests PATCH v4 4/5] configure: Add --target-cpu option

[Jean-Philippe Brucker]

Add the --target-cpu option to let users set the CPU type to run on.
At the moment --processor allows to set both GCC -mcpu flag and QEMU
-cpu. On Arm we'd like to pass `-cpu max` to QEMU in order to enable all
the TCG features by default, and it could also be nice to let users
modify the CPU capabilities by setting extra -cpu options. Since GCC
-mcpu doesn't accept "max" or "host", separate the compiler and QEMU
arguments.

`--processor` is now exclusively for compiler options, as indicated by
its documentation ("processor to compile for"). So use $TARGET_CPU on
RISC-V as well.

Suggested-by: Andrew Jones <andrew.jones at linux.dev>
Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org>
---
 scripts/mkstandalone.sh |  3 ++-
 arm/run                 | 15 +++++++++------
 riscv/run               |  8 ++++----
 configure               | 27 +++++++++++++++++++++++++++
 4 files changed, 42 insertions(+), 11 deletions(-)

diff --git a/scripts/mkstandalone.sh b/scripts/mkstandalone.sh
index 2318a85f..c4ba81f1 100755
--- a/scripts/mkstandalone.sh
+++ b/scripts/mkstandalone.sh
@@ -42,7 +42,8 @@ generate_test ()
 
 	config_export ARCH
 	config_export ARCH_NAME
-	config_export PROCESSOR
+	config_export TARGET_CPU
+	config_export DEFAULT_QEMU_CPU
 
 	echo "echo BUILD_HEAD=$(cat build-head)"
 
diff --git a/arm/run b/arm/run
index efdd44ce..ef585582 100755
--- a/arm/run
+++ b/arm/run
@@ -8,7 +8,7 @@ if [ -z "$KUT_STANDALONE" ]; then
 	source config.mak
 	source scripts/arch-run.bash
 fi
-processor="$PROCESSOR"
+qemu_cpu="$TARGET_CPU"
 
 if [ "$QEMU" ] && [ -z "$ACCEL" ] &&
    [ "$HOST" = "aarch64" ] && [ "$ARCH" = "arm" ] &&
@@ -37,12 +37,15 @@ if [ "$ACCEL" = "kvm" ]; then
 	fi
 fi
 
-if [ "$ACCEL" = "kvm" ] || [ "$ACCEL" = "hvf" ]; then
-	if [ "$HOST" = "aarch64" ] || [ "$HOST" = "arm" ]; then
-		processor="host"
+if [ -z "$qemu_cpu" ]; then
+	if ( [ "$ACCEL" = "kvm" ] || [ "$ACCEL" = "hvf" ] ) &&
+	   ( [ "$HOST" = "aarch64" ] || [ "$HOST" = "arm" ] ); then
+		qemu_cpu="host"
 		if [ "$ARCH" = "arm" ] && [ "$HOST" = "aarch64" ]; then
-			processor+=",aarch64=off"
+			qemu_cpu+=",aarch64=off"
 		fi
+	else
+		qemu_cpu="$DEFAULT_QEMU_CPU"
 	fi
 fi
 
@@ -71,7 +74,7 @@ if $qemu $M -device '?' | grep -q pci-testdev; then
 fi
 
 A="-accel $ACCEL$ACCEL_PROPS"
-command="$qemu -nodefaults $M $A -cpu $processor $chr_testdev $pci_testdev"
+command="$qemu -nodefaults $M $A -cpu $qemu_cpu $chr_testdev $pci_testdev"
 command+=" -display none -serial stdio"
 command="$(migration_cmd) $(timeout_cmd) $command"
 
diff --git a/riscv/run b/riscv/run
index e2f5a922..2bd42ad8 100755
--- a/riscv/run
+++ b/riscv/run
@@ -11,12 +11,12 @@ fi
 
 # Allow user overrides of some config.mak variables
 mach=$MACHINE_OVERRIDE
-processor=$PROCESSOR_OVERRIDE
+qemu_cpu=$QEMU_CPU_OVERRIDE
 firmware=$FIRMWARE_OVERRIDE
 
-[ "$PROCESSOR" = "$ARCH" ] && PROCESSOR="max"
 : "${mach:=virt}"
-: "${processor:=$PROCESSOR}"
+: "${qemu_cpu:=$TARGET_CPU}"
+: "${qemu_cpu:=$DEFAULT_QEMU_CPU}"
 : "${firmware:=$FIRMWARE}"
 [ "$firmware" ] && firmware="-bios $firmware"
 
@@ -32,7 +32,7 @@ fi
 mach="-machine $mach"
 
 command="$qemu -nodefaults -nographic -serial mon:stdio"
-command+=" $mach $acc $firmware -cpu $processor "
+command+=" $mach $acc $firmware -cpu $qemu_cpu "
 command="$(migration_cmd) $(timeout_cmd) $command"
 
 if [ "$UEFI_SHELL_RUN" = "y" ]; then
diff --git a/configure b/configure
index b4875ef3..63367bbc 100755
--- a/configure
+++ b/configure
@@ -23,6 +23,24 @@ function get_default_processor()
     esac
 }
 
+# Return the default CPU type to run on
+function get_default_qemu_cpu()
+{
+    local arch="$1"
+
+    case "$arch" in
+    "arm")
+        echo "cortex-a15"
+        ;;
+    "arm64")
+        echo "cortex-a57"
+        ;;
+    "riscv32" | "riscv64")
+        echo "max"
+        ;;
+    esac
+}
+
 srcdir=$(cd "$(dirname "$0")"; pwd)
 prefix=/usr/local
 cc=gcc
@@ -52,6 +70,7 @@ earlycon=
 console=
 efi=
 efi_direct=
+target_cpu=
 
 # Enable -Werror by default for git repositories only (i.e. developer builds)
 if [ -e "$srcdir"/.git ]; then
@@ -70,6 +89,9 @@ usage() {
 	    --arch=ARCH            architecture to compile for ($arch). ARCH can be one of:
 	                           arm, arm64, i386, ppc64, riscv32, riscv64, s390x, x86_64
 	    --processor=PROCESSOR  processor to compile for ($processor)
+	    --target-cpu=CPU       the CPU model to run on. If left unset, the run script
+	                           selects the best value based on the host system and the
+	                           test configuration.
 	    --target=TARGET        target platform that the tests will be running on (qemu or
 	                           kvmtool, default is qemu) (arm/arm64 only)
 	    --cross-prefix=PREFIX  cross compiler prefix
@@ -146,6 +168,9 @@ while [[ $optno -le $argc ]]; do
         --processor)
 	    processor="$arg"
 	    ;;
+	--target-cpu)
+	    target_cpu="$arg"
+	    ;;
 	--target)
 	    target="$arg"
 	    ;;
@@ -471,6 +496,8 @@ ARCH=$arch
 ARCH_NAME=$arch_name
 ARCH_LIBDIR=$arch_libdir
 PROCESSOR=$processor
+TARGET_CPU=$target_cpu
+DEFAULT_QEMU_CPU=$(get_default_qemu_cpu $arch)
 CC=$cc
 CFLAGS=$cflags
 LD=$cross_prefix$ld
-- 
2.49.0