[PATCH v1 4/4] selftests/nolibc: add some notes about qemu tools

[Zhangjin Wu]

Almost all distributions provide qemu-system-$(XARCH), their firmwares
and qemu-$(XARCH), but for the new riscv and loongarch, users may still
need to download external firmwares or compile qemu from scratch, let's
add some notes about them.

Signed-off-by: Zhangjin Wu <falcon@xxxxxxxxxxx>
---
 tools/testing/selftests/nolibc/Makefile | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 9cd6dc0e8b75..1e92bb5138db 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -100,6 +100,18 @@ DEFCONFIG            = $(DEFCONFIG_$(XARCH))
 TEST =
 
 # QEMU_ARCH: arch names used by qemu
+#
+# Notes:
+# - qemu-system of riscv may require latest firmware from
+#   https://github.com/riscv-software-src/opensbi/releases/
+# - qemu-system of loongarch may require latest firmware from
+#   https://github.com/loongson/Firmware/tree/main/LoongArchVirtMachine
+#
+# If qemu-$(XARCH) or qemu-system-$(XARCH) is missing from software repository,
+# please compile them with help from https://wiki.qemu.org/Documentation
+#
+# To specify a firmware, please pass QEMU_ARGS_EXTRA="-bios dir/to/firmware"
+
 QEMU_ARCH_i386       = i386
 QEMU_ARCH_x86_64     = x86_64
 QEMU_ARCH_x86        = x86_64
@@ -114,7 +126,7 @@ QEMU_ARCH_s390       = s390x
 QEMU_ARCH_loongarch  = loongarch64
 QEMU_ARCH            = $(QEMU_ARCH_$(XARCH))
 
-# QEMU_ARGS : some arch-specific args to pass to qemu
+# QEMU_ARGS: some arch-specific args to pass to qemu
 QEMU_ARGS_i386       = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_x86_64     = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_x86        = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
-- 
2.25.1