[PATCH] misc: pvpanic: add crash loaded event

[zhenwei pi <pizhenwei@bytedance.com>]

Some users prefer kdump tools to generate guest kernel dumpfile,
at the same time, need a out-of-band kernel panic event.

Currently if booting guest kernel with 'crash_kexec_post_notifiers',
QEMU will recieve PVPANIC_PANICKED event and stop VM. If booting
guest kernel without 'crash_kexec_post_notifiers', guest will not
call notifier chain.

Add PVPANIC_CRASH_LOADED bit for pvpanic event, it means that guest
actually hit a kernel panic, but kernel wants to handle by itself.

Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
 drivers/misc/pvpanic.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/pvpanic.c b/drivers/misc/pvpanic.c
index 95ff7c5a1dfb..a8cc96c90550 100644
--- a/drivers/misc/pvpanic.c
+++ b/drivers/misc/pvpanic.c
@@ -10,6 +10,7 @@
 
 #include <linux/acpi.h>
 #include <linux/kernel.h>
+#include <linux/kexec.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
@@ -19,6 +20,7 @@
 static void __iomem *base;
 
 #define PVPANIC_PANICKED        (1 << 0)
+#define PVPANIC_CRASH_LOADED    (1 << 1)
 
 MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
 MODULE_DESCRIPTION("pvpanic device driver");
@@ -34,7 +36,13 @@ static int
 pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
 		     void *unused)
 {
-	pvpanic_send_event(PVPANIC_PANICKED);
+	unsigned int event = PVPANIC_PANICKED;
+
+	if (kexec_crash_loaded())
+		event = PVPANIC_CRASH_LOADED;
+
+	pvpanic_send_event(event);
+
 	return NOTIFY_DONE;
 }
 
-- 
2.11.0