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>

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;
 	}