[PATCH] x86: print microcode revision on PEBs errors

["Michael S. Tsirkin" <mst@redhat.com>]

On Sandy bridge CPUs with old microcode, PEBs
fails and suggests a microcode update.
Print out the required and the actual revision to
make it easier to figure out what's wrong.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 arch/x86/kernel/cpu/perf_event_intel.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index f31a165..81f2789 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -2105,6 +2105,8 @@ static int intel_snb_pebs_broken(int cpu)
 		}
 	}
 
+	pr_info("PEBS checking: microcode 0x%x min legal 0x%x\n",
+		cpu_data(cpu).microcode, rev);
 	return (cpu_data(cpu).microcode < rev);
 }
 
-- 
MST