linux-kernel - [PATCH 4/11] arch/x86/kvm: Correct NULL test

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Date:	Sat, 6 Feb 2010 09:43:03 +0100 (CET)
From:	Julia Lawall <julia@...u.dk>
To:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [PATCH 4/11] arch/x86/kvm: Correct NULL test

From: Julia Lawall <julia@...u.dk>

msr was tested above, so the second test is not needed.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@r@
expression *x;
expression e;
identifier l;
@@

if (x == NULL || ...) {
    ... when forall
    return ...; }
... when != goto l;
    when != x = e
    when != &x
*x == NULL
// </smpl>

Signed-off-by: Julia Lawall <julia@...u.dk>

---
 arch/x86/kvm/vmx.c                  |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7375ae1..422bfc8 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1609,8 +1609,6 @@ static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
 	 */
 	vmx_load_host_state(to_vmx(vcpu));
 	vcpu->arch.shadow_efer = efer;
-	if (!msr)
-		return;
 	if (efer & EFER_LMA) {
 		vmcs_write32(VM_ENTRY_CONTROLS,
 			     vmcs_read32(VM_ENTRY_CONTROLS) |
--
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