linux-kernel - [PATCH] X86: don't print a warning when MTRR are blank and running in KVM

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Date:	Thu, 21 Feb 2008 15:50:14 +0100
From:	"Joerg Roedel" <joerg.roedel@....com>
To:	tglx@...utronix.de, mingo@...hat.com
cc:	linux-kernel@...r.kernel.org, "Joerg Roedel" <joerg.roedel@....com>
Subject: [PATCH] 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@....com>
---
 arch/x86/kernel/cpu/mtrr/main.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index b6e136f..47e624c 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;
@@ -687,12 +688,14 @@ 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) {
+	if (!highest_pfn && !kvm_para_available()) {
 		printk(KERN_WARNING "WARNING: strange, CPU MTRRs all blank?\n");
 		WARN_ON(1);
-		return 0;
 	}
 
+	if (!highest_pfn)
+		return 0;
+
 	if (highest_pfn < end_pfn) {
 		printk(KERN_WARNING "WARNING: BIOS bug: CPU MTRRs don't cover"
 			" all of memory, losing %luMB of RAM.\n",
-- 
1.5.3.7



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