x86: don't print a warning when MTRR are blank and running in KVM

Inside a KVM virtual machine the MTRRs are usually blank. This confuses Linux
and causes a warning message at boot. This patch removes that warning message
when running Linux as a KVM guest.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 6 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index c8fda3eb3d7e..be83336fddba 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -43,6 +43,7 @@
 #include <asm/uaccess.h>
 #include <asm/processor.h>
 #include <asm/msr.h>
+#include <asm/kvm_para.h>
 #include "mtrr.h"
 
 u32 num_var_ranges = 0;
@@ -689,8 +690,11 @@ int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
 
         /* kvm/qemu doesn't have mtrr set right, don't trim them all */
         if (!highest_pfn) {
-                printk(KERN_WARNING "WARNING: strange, CPU MTRRs all blank?\n");
-                WARN_ON(1);
+                if (!kvm_para_available()) {
+                        printk(KERN_WARNING
+                                "WARNING: strange, CPU MTRRs all blank?\n");
+                        WARN_ON(1);
+                }
                 return 0;
         }