pvpanic: implement crashloaded event handling

Handle bit 1 write, then post event to monitor.

Suggested by Paolo, declear a new event, using GUEST_PANICKED could
cause upper layers to react by shutting down or rebooting the guest.

In advance for extention, add GuestPanicInformation in event message.

Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Message-Id: <20200114023102.612548-3-pizhenwei@bytedance.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

docs/specs/pvpanic.txt

@@ -19,9 +19,10 @@ Software should set only bits both itself and the device recognize.
 
 Bit Definition
 --------------
-bit 0: setting it indicates a guest panic has happened.
-bit 1: named crashloaded. setting it indicates a guest panic and run
-       kexec to handle error by guest itself.
+bit 0: a guest panic has happened and should be processed by the host
+bit 1: a guest panic has happened and will be handled by the guest;
+       the host should record it or report it, but should not affect
+       the execution of the guest.
 
 ACPI Interface
 --------------
@@ -30,13 +31,12 @@ pvpanic device is defined with ACPI ID "QEMU0001". Custom methods:
 
 RDPT:       To determine whether guest panic notification is supported.
 Arguments:  None
-Return:     Returns a byte, bit 0 set to indicate guest panic
-            notification is supported. Other bits are reserved and
-            should be ignored.
+Return:     Returns a byte, with the same semantics as the I/O port
+            interface.
 
 WRPT:       To send a guest panic event
-Arguments:  Arg0 is a byte, with bit 0 set to indicate guest panic has
-            happened. Other bits are reserved and should be cleared.
+Arguments:  Arg0 is a byte to be written, with the same semantics as
+            the I/O interface.
 Return:     None
 
 The ACPI device will automatically refer to the right port in case it

hw/misc/pvpanic.c

@@ -21,11 +21,13 @@
 #include "hw/qdev-properties.h"
 #include "hw/misc/pvpanic.h"
 
-/* The bit of supported pv event */
+/* The bit of supported pv event, TODO: include uapi header and remove this */
 #define PVPANIC_F_PANICKED      0
+#define PVPANIC_F_CRASHLOADED   1
 
 /* The pv event value */
 #define PVPANIC_PANICKED        (1 << PVPANIC_F_PANICKED)
+#define PVPANIC_CRASHLOADED     (1 << PVPANIC_F_CRASHLOADED)
 
 #define ISA_PVPANIC_DEVICE(obj)    \
     OBJECT_CHECK(PVPanicState, (obj), TYPE_PVPANIC)
@@ -34,7 +36,7 @@ static void handle_event(int event)
 {
     static bool logged;
 
-    if (event & ~PVPANIC_PANICKED && !logged) {
+    if (event & ~(PVPANIC_PANICKED | PVPANIC_CRASHLOADED) && !logged) {
         qemu_log_mask(LOG_GUEST_ERROR, "pvpanic: unknown event %#x.\n", event);
         logged = true;
     }
@@ -43,6 +45,11 @@ static void handle_event(int event)
         qemu_system_guest_panicked(NULL);
         return;
     }
+
+    if (event & PVPANIC_CRASHLOADED) {
+        qemu_system_guest_crashloaded(NULL);
+        return;
+    }
 }
 
 #include "hw/isa/isa.h"

include/sysemu/runstate.h

@@ -63,6 +63,7 @@ ShutdownCause qemu_reset_requested_get(void);
 void qemu_system_killed(int signal, pid_t pid);
 void qemu_system_reset(ShutdownCause reason);
 void qemu_system_guest_panicked(GuestPanicInformation *info);
+void qemu_system_guest_crashloaded(GuestPanicInformation *info);
 
 #endif
 

qapi/run-state.json

@@ -356,6 +356,26 @@
 { 'event': 'GUEST_PANICKED',
   'data': { 'action': 'GuestPanicAction', '*info': 'GuestPanicInformation' } }
 
+##
+# @GUEST_CRASHLOADED:
+#
+# Emitted when guest OS crash loaded is detected
+#
+# @action: action that has been taken, currently always "run"
+#
+# @info: information about a panic
+#
+# Since: 5.0
+#
+# Example:
+#
+# <- { "event": "GUEST_CRASHLOADED",
+#      "data": { "action": "run" } }
+#
+##
+{ 'event': 'GUEST_CRASHLOADED',
+  'data': { 'action': 'GuestPanicAction', '*info': 'GuestPanicInformation' } }
+
 ##
 # @GuestPanicAction:
 #
@@ -363,10 +383,10 @@
 #
 # @pause: system pauses
 #
-# Since: 2.1 (poweroff since 2.8)
+# Since: 2.1 (poweroff since 2.8, run since 5.0)
 ##
 { 'enum': 'GuestPanicAction',
-  'data': [ 'pause', 'poweroff' ] }
+  'data': [ 'pause', 'poweroff', 'run' ] }
 
 ##
 # @GuestPanicInformationType:

vl.c

@@ -1468,6 +1468,18 @@ void qemu_system_guest_panicked(GuestPanicInformation *info)
     }
 }
 
+void qemu_system_guest_crashloaded(GuestPanicInformation *info)
+{
+    qemu_log_mask(LOG_GUEST_ERROR, "Guest crash loaded");
+
+    qapi_event_send_guest_crashloaded(GUEST_PANIC_ACTION_RUN,
+                                   !!info, info);
+
+    if (info) {
+        qapi_free_GuestPanicInformation(info);
+    }
+}
+
 void qemu_system_reset_request(ShutdownCause reason)
 {
     if (no_reboot && reason != SHUTDOWN_CAUSE_SUBSYSTEM_RESET) {