kvm: ensure hard lockup detection is disabled by default

Use watchdog_enable_hardlockup_detector() to set hard lockup detection's
default value to false.  It's risky to run this detection in a guest, as
false positives are easy to trigger, especially if the host is
overcommitted.

Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 3dd8e2c..95c3cb1 100644 (file)
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -35,6 +35,7 @@
 #include <linux/slab.h>
 #include <linux/kprobes.h>
 #include <linux/debugfs.h>
+#include <linux/nmi.h>
 #include <asm/timer.h>
 #include <asm/cpu.h>
 #include <asm/traps.h>
@@ -499,6 +500,13 @@ void __init kvm_guest_init(void)
 #else
        kvm_guest_cpu_init();
 #endif
+
+       /*
+        * Hard lockup detection is enabled by default. Disable it, as guests
+        * can get false positives too easily, for example if the host is
+        * overcommitted.
+        */
+       watchdog_enable_hardlockup_detector(false);
 }
 
 static noinline uint32_t __kvm_cpuid_base(void)