[PATCH 4/4] selftests: liveupdate: Add riscv support

[Chen Pei <cp0613@linux.alibaba.com>]

Teach the live update vmtest runner about riscv64: map the target to ARCH
riscv, describe the QEMU virt machine, the kernel image and its console,
and add the arch config fragment holding the three symbols needed to get
a console on the virt machine's 16550A port.

KHO is the only dependency of LIVEUPDATE (kernel/liveupdate/Kconfig), so
now that riscv has KHO the LUO tests only need the runner to stop
rejecting the architecture.

Add riscv64 to the CROSS_COMPILE auto-detection list and to the target
list of the batch runner as well, matching the existing aarch64/x86_64
entries.

Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
---
Test: qemu-system-riscv64 (virt, -cpu max, -m 1G, -smp 2, TCG), in-tree
runner "tools/testing/selftests/liveupdate/vmtest.sh -t riscv64 -T <suite>",
all four suites:

  luo_kexec_simple:    SIMPLE KEXEC TEST PASSED
  luo_multi_session:   MULTI-SESSION KEXEC TEST PASSED
  luo_stress_files:    MANY-FILES KEXEC TEST PASSED (500 files)
  luo_stress_sessions: MANY-SESSIONS KEXEC TEST PASSED (2000 sessions)

The simple suite's serial log shows the full handover round trip:

  KHO: found kexec handover data.
  luo: Retrieved live update data, liveupdate number: 1
  # [STAGE 2] Test data verified successfully.
  --- SIMPLE KEXEC TEST PASSED ---

 tools/testing/selftests/liveupdate/config.riscv64 | 3 +++
 tools/testing/selftests/liveupdate/run-vmtests.sh | 2 +-
 tools/testing/selftests/liveupdate/vmtest.sh      | 8 +++++++-
 3 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/liveupdate/config.riscv64

diff --git a/tools/testing/selftests/liveupdate/config.riscv64 b/tools/testing/selftests/liveupdate/config.riscv64
new file mode 100644
index 000000000000..edbc551199b0
--- /dev/null
+++ b/tools/testing/selftests/liveupdate/config.riscv64
@@ -0,0 +1,3 @@
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_OF_PLATFORM=y
diff --git a/tools/testing/selftests/liveupdate/run-vmtests.sh b/tools/testing/selftests/liveupdate/run-vmtests.sh
index d656ce58c5a7..2e3f5f6f96b3 100755
--- a/tools/testing/selftests/liveupdate/run-vmtests.sh
+++ b/tools/testing/selftests/liveupdate/run-vmtests.sh
@@ -4,7 +4,7 @@
 SCRIPT_DIR=$(dirname "$(realpath "$0")")
 TEST_RUNNER="$SCRIPT_DIR/vmtest.sh"
 
-TARGETS=("x86_64" "aarch64")
+TARGETS=("x86_64" "aarch64" "riscv64")
 
 GREEN='\033[0;32m'
 RED='\033[0;31m'
diff --git a/tools/testing/selftests/liveupdate/vmtest.sh b/tools/testing/selftests/liveupdate/vmtest.sh
index 64fd2ab55b76..ee554d889e1b 100755
--- a/tools/testing/selftests/liveupdate/vmtest.sh
+++ b/tools/testing/selftests/liveupdate/vmtest.sh
@@ -25,6 +25,10 @@ function get_arch_conf() {
 		QEMU_CMD="qemu-system-x86_64"
 		KERNEL_IMAGE="bzImage"
 		KERNEL_CMDLINE="console=ttyS0"
+	elif [[ "$arch" == "riscv" ]]; then
+		QEMU_CMD="qemu-system-riscv64 -M virt -cpu max"
+		KERNEL_IMAGE="Image"
+		KERNEL_CMDLINE="console=ttyS0"
 	else
 		echo "Unsupported architecture: $arch"
 		exit 1
@@ -37,7 +41,7 @@ $0 [-d build_dir] [-j jobs] [-t target_arch] [-T test_name] [-w workspace_dir] [
 Options:
 	-d)	path to the kernel build directory (default: .luo_test_build.<arch>)
 	-j)	number of jobs for compilation
-	-t)	run test for target_arch (aarch64, x86_64)
+	-t)	run test for target_arch (aarch64, x86_64, riscv64)
 	-T)	test name to run (default: luo_kexec_simple)
 	-w)	custom workspace directory (default: creates temp dir)
 	-k)	keep workspace directory after successful test
@@ -87,6 +91,7 @@ function detect_cross_compile() {
 	case "$target" in
 		aarch64) candidate="aarch64-linux-gnu-" ;;
 		x86_64)  candidate="x86_64-linux-gnu-" ;;
+		riscv64) candidate="riscv64-linux-gnu-" ;;
 		*)       skip "Auto-detection for target '$target' not supported. Please set CROSS_COMPILE manually." ;;
 	esac
 
@@ -194,6 +199,7 @@ function target_to_arch() {
 	case $target in
 	     aarch64) echo "arm64" ;;
 	     x86_64) echo "x86" ;;
+	     riscv64) echo "riscv" ;;
 	     *) skip "architecture $target is not supported"
 	esac
 }
-- 
2.50.1