linux-kernel - [PATCH v2 2/2] misc: pvpanic: add crash loaded event

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Message-Id: <20191215034840.2273096-3-pizhenwei@bytedance.com>
Date:   Sun, 15 Dec 2019 11:48:40 +0800
From:   zhenwei pi <pizhenwei@...edance.com>
To:     arnd@...db.de, gregkh@...uxfoundation.org, peng.hao2@....com.cn
Cc:     hutao@...fujitsu.com, linux-kernel@...r.kernel.org,
        pizhenwei@...edance.com
Subject: [PATCH v2 2/2] misc: pvpanic: add crash loaded event

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 receive 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
kernel actually hit a kernel panic, but the guest kernel wants to
handle by itself.

Signed-off-by: zhenwei pi <pizhenwei@...edance.com>
---
 drivers/misc/pvpanic.c      | 9 ++++++++-
 include/uapi/misc/pvpanic.h | 1 +
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/pvpanic.c b/drivers/misc/pvpanic.c
index 3f0de3be0a19..a6e1a8983e1f 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>
@@ -33,7 +34,13 @@ 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;
 }
 
diff --git a/include/uapi/misc/pvpanic.h b/include/uapi/misc/pvpanic.h
index cae69a822b25..54b7485390d3 100644
--- a/include/uapi/misc/pvpanic.h
+++ b/include/uapi/misc/pvpanic.h
@@ -4,5 +4,6 @@
 #define __PVPANIC_H__
 
 #define PVPANIC_PANICKED	(1 << 0)
+#define PVPANIC_CRASH_LOADED	(1 << 1)
 
 #endif /* __PVPANIC_H__ */
-- 
2.11.0