plat/*: Signal shutdown cause on QEMU

This uses the `isa-debug-exit` device to pass an exit code to QEMU. By default this device is not available but can be enabled using the `-device isa-debug-exit` switch on the QEMU command-line. Github-Fixes: unikraft#1018 Signed-off-by: Marco Schlumpp <marco@unikraft.io>
mschlumpp · Aug 3, 2023 · 7594d1a · 7594d1a
1 parent d21fb22
commit 7594d1a
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Showing 5 changed files with 33 additions and 10 deletions.
diff --git a/plat/common/arm/cpu_native.c b/plat/common/arm/cpu_native.c
@@ -66,7 +66,7 @@ void reset(void)
 }
 
 /* Systems support PSCI >= 0.2 can do system off from PSCI */
-void system_off(void)
+void system_off(enum ukplat_gstate request __unused)
 {
 	struct smccc_args smccc_arguments = {0};
 

diff --git a/plat/common/include/arm/arm64/cpu.h b/plat/common/include/arm/arm64/cpu.h
@@ -35,6 +35,7 @@
 
 #include <inttypes.h>
 #include <uk/essentials.h>
+#include <uk/plat/bootstrap.h>
 #include <uk/alloc.h>
 #include <uk/assert.h>
 #include <arm/smccc.h>
@@ -57,7 +58,7 @@ extern smccc_conduit_fn_t smccc_psci_call;
 /* CPU native APIs */
 void halt(void);
 void reset(void);
-void system_off(void);
+void system_off(enum ukplat_gstate request);
 #ifdef CONFIG_HAVE_SMP
 int cpu_on(__lcpuid id, __paddr_t entry, void *arg);
 #endif /* CONFIG_HAVE_SMP */

diff --git a/plat/common/include/x86/cpu.h b/plat/common/include/x86/cpu.h
@@ -38,7 +38,7 @@
 #include <string.h>
 
 void halt(void);
-void system_off(void);
+void system_off(enum ukplat_gstate request);
 
 static inline void cpuid(__u32 fn, __u32 subfn,
 			 __u32 *eax, __u32 *ebx,

diff --git a/plat/common/x86/cpu_native.c b/plat/common/x86/cpu_native.c
@@ -46,7 +46,18 @@ unsigned long read_cr2(void)
 	return cr2;
 }
 
-void system_off(void)
+#ifdef CONFIG_KVM_VMM_QEMU
+/**
+ * Trigger an exit() in QEMU with the code `value << 1 | 1`.
+ * @param value the value used in the calculation of the exit code
+ */
+static void qemu_debug_exit(int value)
+{
+	outw(0x501, value);
+}
+#endif /* CONFIG_KVM_VMM_QEMU */
+
+void system_off(enum ukplat_gstate request __maybe_unused)
 {
 #ifdef CONFIG_KVM_VMM_FIRECRACKER
 	/* Trigger the reset line via the PS/2 controller. On firecracker
@@ -55,6 +66,17 @@ void system_off(void)
 	outb(0x64, 0xFE);
 #endif /* CONFIG_KVM_VMM_FIRECRACKER */
 
+#ifdef CONFIG_KVM_VMM_QEMU
+	/* If we are crashing then try to exit QEMU with the isa-debug-exit
+	 * device.
+	 * Should be harmless if it is not present. This is used to enable
+	 * automated tests on virtio.  Note that the actual QEMU exit() status
+	 * will be 85 ('S', 42 << 1 | 1).
+	 */
+	if (request == UKPLAT_CRASH)
+		qemu_debug_exit(42);
+#endif /* CONFIG_KVM_VMM_QEMU */
+
 	/*
 	 * Perform an ACPI shutdown by writing (SLP_TYPa | SLP_EN) to PM1a_CNT.
 	 * Generally speaking, we'd have to jump through a lot of hoops to
@@ -64,11 +86,11 @@ void system_off(void)
 	 */
 	outw(0x604, 0x2000);
 
+#ifdef CONFIG_KVM_VMM_QEMU
 	/*
 	 * If that didn't work for whatever reason, try poking the QEMU
-	 * "isa-debug-exit" device to "shutdown". Should be harmless if it is
-	 * not present. This is used to enable automated tests on virtio.  Note
-	 * that the actual QEMU exit() status will be 83 ('S', 41 << 1 | 1).
+	 * "isa-debug-exit" device to "shutdown".
 	 */
-	outw(0x501, 41);
+	qemu_debug_exit(41);
+#endif /* CONFIG_KVM_VMM_QEMU */
 }
diff --git a/plat/kvm/shutdown.c b/plat/kvm/shutdown.c
@@ -30,12 +30,12 @@
 static void cpu_halt(void) __noreturn;
 
 /* TODO: implement CPU reset */
-void ukplat_terminate(enum ukplat_gstate request __unused)
+void ukplat_terminate(enum ukplat_gstate request)
 {
 	uk_pr_info("Unikraft halted\n");
 
 	/* Try to make system off */
-	system_off();
+	system_off(request);
 
 	/*
 	 * If we got here, there is no way to initiate "shutdown" on virtio