integration-test: fix integration guest runner shell checks

Keep the QEMU and Cloud Hypervisor invocations in the same shell as the rc=$$? capture so failures are reported correctly, and make the shared integration-test toolchain explicitly include the built-in riscv64gc-unknown-none-elf target used by the MMIO guest.

Author: phip1611

integration-test/riscv/Makefile

@@ -19,7 +19,7 @@ run: | build
 		-monitor none \
 		-no-reboot \
 		-nodefaults \
-		-serial file:serial.qemu.mmio-riscv.txt
+		-serial file:serial.qemu.mmio-riscv.txt; \
 	rc=$$? ; \
 	if [ $$rc -ne 0 ]; then \
 		echo "QEMU RISC-V MMIO Test Run Failed. rc=$$rc" >&2 ; \

integration-test/rust-toolchain.toml

@@ -6,7 +6,10 @@
 # rustc 1.96 - nightly needed for the build-std feature
 channel = "nightly-2026-03-17"
 profile = "minimal"
-targets = [ "x86_64-unknown-linux-gnu" ]
+targets = [
+  "x86_64-unknown-linux-gnu",
+  "riscv64gc-unknown-none-elf",
+]
 components = [
   "cargo",
   "clippy",

integration-test/x86/Makefile

@@ -40,7 +40,7 @@ run_chv: | build
 	  --console off \
 	  --debug-console tty \
 	  --serial file=serial.chv.pio.txt \
-	  --kernel target/x86-unknown-none/release/kernel-x86.elf64
+	  --kernel target/x86-unknown-none/release/kernel-x86.elf64; \
 	rc=$$? ; \
 	if [ $$rc -ne 0 ]; then \
 		echo "Cloud Hypervisor Test Run Failed. rc=$$rc" >&2 ; \