From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: KVM: pvmmu breakage with gcc 4.3.0
Date: Wed, 25 Jun 2008 23:10:47 -0300
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Cc: Alexandre Oliva <aoliva@redhat.com>,
	kvm-devel <kvm@vger.kernel.org>
To: Avi Kivity <avi@qumranet.com>,
	Anthony Liguori <aliguori@us.ibm.com>
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Some pvmmu functions store their commands on stack, and newer GCC
versions conclude that these commands are unused.

So stick an inline asm statement to convince the compiler otherwise.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>


diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 8b7a3cf..c892752 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -55,6 +55,12 @@ static void kvm_mmu_op(void *buffer, unsigned len)
 	int r;
 	unsigned long a1, a2;
 
+	/*
+   	 * GCC 4.3.0 concludes that on-stack kvm_mmu_op* is unused and
+   	 * optimizes its initialization away.
+ 	 */
+        asm ("" : : "p" (buffer));
+
 	do {
 		a1 = __pa(buffer);
 		a2 = 0;   /* on i386 __pa() always returns <4G */