linux-kernel - [PATCH] KVM: VMX: replace move_msr

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Date:   Fri, 3 Nov 2017 17:58:19 -0500
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Subject: [PATCH] KVM: VMX: replace move_msr_up with swap macro

Function move_msr_up is used to _manually_ swap MSR entries in MSR array.
This function can be removed and replaced using the swap macro instead.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
---
The new lines are over 80 characters, but I think in this case that is
preferable over splitting them.

 arch/x86/kvm/vmx.c | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e6c8ffa..210e491 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2544,18 +2544,6 @@ static bool vmx_invpcid_supported(void)
 	return cpu_has_vmx_invpcid() && enable_ept;
 }
 
-/*
- * Swap MSR entry in host/guest MSR entry array.
- */
-static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
-{
-	struct shared_msr_entry tmp;
-
-	tmp = vmx->guest_msrs[to];
-	vmx->guest_msrs[to] = vmx->guest_msrs[from];
-	vmx->guest_msrs[from] = tmp;
-}
-
 static void vmx_set_msr_bitmap(struct kvm_vcpu *vcpu)
 {
 	unsigned long *msr_bitmap;
@@ -2600,28 +2588,28 @@ static void setup_msrs(struct vcpu_vmx *vmx)
 	if (is_long_mode(&vmx->vcpu)) {
 		index = __find_msr_index(vmx, MSR_SYSCALL_MASK);
 		if (index >= 0)
-			move_msr_up(vmx, index, save_nmsrs++);
+			swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
 		index = __find_msr_index(vmx, MSR_LSTAR);
 		if (index >= 0)
-			move_msr_up(vmx, index, save_nmsrs++);
+			swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
 		index = __find_msr_index(vmx, MSR_CSTAR);
 		if (index >= 0)
-			move_msr_up(vmx, index, save_nmsrs++);
+			swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
 		index = __find_msr_index(vmx, MSR_TSC_AUX);
 		if (index >= 0 && guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP))
-			move_msr_up(vmx, index, save_nmsrs++);
+			swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
 		/*
 		 * MSR_STAR is only needed on long mode guests, and only
 		 * if efer.sce is enabled.
 		 */
 		index = __find_msr_index(vmx, MSR_STAR);
 		if ((index >= 0) && (vmx->vcpu.arch.efer & EFER_SCE))
-			move_msr_up(vmx, index, save_nmsrs++);
+			swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
 	}
 #endif
 	index = __find_msr_index(vmx, MSR_EFER);
 	if (index >= 0 && update_transition_efer(vmx, index))
-		move_msr_up(vmx, index, save_nmsrs++);
+		swap(vmx->guest_msrs[index], vmx->guest_msrs[save_nmsrs++]);
 
 	vmx->save_nmsrs = save_nmsrs;
 
-- 
2.7.4