[PATCH] x86, add hypervisor name to dump_stack()

[Prarit Bhargava <prarit@redhat.com>]

Debugging crash, panics, stack trace WARN_ONs, etc., from both virtual and
bare-metal boots can get difficult very quickly.  While there are ways to
decipher the output and determine if the output is from a virtual guest,
the in-kernel hypervisors now have a single registration point and set
x86_hyper.  We can use this to output a single extra line on virtual
machines that indicates the hypervisor type.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Marcelo Tostatti <mtosatti@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kvm@vger.kernel.org
Cc: x86@kernel.org
---
 arch/x86/kernel/dumpstack.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index ae42418b..75a635e 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -17,6 +17,7 @@
 #include <linux/sysfs.h>
 
 #include <asm/stacktrace.h>
+#include <asm/hypervisor.h>
 
 
 int panic_on_unrecovered_nmi;
@@ -193,6 +194,8 @@ void dump_stack(void)
 		init_utsname()->release,
 		(int)strcspn(init_utsname()->version, " "),
 		init_utsname()->version);
+	if (x86_hyper && x86_hyper->name)
+		printk("Hypervisor: %s\n",  x86_hyper->name);
 	show_trace(NULL, NULL, &stack, bp);
 }
 EXPORT_SYMBOL(dump_stack);
-- 
1.7.9.3