diff --git a/tools/testing/selftests/wireguard/qemu/arch/riscv32.config b/tools/testing/selftests/wireguard/qemu/arch/riscv32.config
index 2fc36efb166dc..a7f8e8a956259 100644
--- a/tools/testing/selftests/wireguard/qemu/arch/riscv32.config
+++ b/tools/testing/selftests/wireguard/qemu/arch/riscv32.config
@@ -3,6 +3,7 @@ CONFIG_ARCH_RV32I=y
 CONFIG_MMU=y
 CONFIG_FPU=y
 CONFIG_SOC_VIRT=y
+CONFIG_RISCV_ISA_FALLBACK=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y
diff --git a/tools/testing/selftests/wireguard/qemu/arch/riscv64.config b/tools/testing/selftests/wireguard/qemu/arch/riscv64.config
index dc266f3b19155..daeb3e5e09658 100644
--- a/tools/testing/selftests/wireguard/qemu/arch/riscv64.config
+++ b/tools/testing/selftests/wireguard/qemu/arch/riscv64.config
@@ -2,6 +2,7 @@ CONFIG_ARCH_RV64I=y
 CONFIG_MMU=y
 CONFIG_FPU=y
 CONFIG_SOC_VIRT=y
+CONFIG_RISCV_ISA_FALLBACK=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y