[PATCH] KVM: arm/arm64: prefer IS_ENABLED to a static variable

[PATCH] KVM: arm/arm64: prefer IS_ENABLED to a static variable

[Paolo Bonzini]

IS_ENABLED gives compile-time checking and keeps the code clearer.

The one exception is inside kvm_vm_ioctl_check_extension, where
the established idiom is to wrap the case labels with an #ifdef.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
--
	Untested...
---
 arch/arm/kvm/arm.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 07e7eb1d7ab6..706769fb0f2e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -61,8 +61,6 @@ static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
 static u8 kvm_next_vmid;
 static DEFINE_SPINLOCK(kvm_vmid_lock);
 
-static bool vgic_present;
-
 static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
 {
 	BUG_ON(preemptible());
@@ -172,9 +170,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 {
 	int r;
 	switch (ext) {
+#ifdef CONFIG_KVM_ARM_VGIC
 	case KVM_CAP_IRQCHIP:
-		r = vgic_present;
-		break;
+#endif
 	case KVM_CAP_DEVICE_CTRL:
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_SYNC_MMU:
@@ -831,7 +829,7 @@ static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
 
 	switch (dev_id) {
 	case KVM_ARM_DEVICE_VGIC_V2:
-		if (!vgic_present)
+		if (!IS_ENABLED(CONFIG_KVM_ARM_VGIC))
 			return -ENXIO;
 		return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
 	default:
@@ -847,10 +845,9 @@ long kvm_arch_vm_ioctl(struct file *filp,
 
 	switch (ioctl) {
 	case KVM_CREATE_IRQCHIP: {
-		if (vgic_present)
-			return kvm_vgic_create(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
-		else
+		if (!IS_ENABLED(CONFIG_KVM_ARM_VGIC))
 			return -ENXIO;
+		return kvm_vgic_create(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
 	}
 	case KVM_ARM_SET_DEVICE_ADDR: {
 		struct kvm_arm_device_addr dev_addr;
@@ -1035,10 +1032,6 @@ static int init_hyp_mode(void)
 	if (err)
 		goto out_free_context;
 
-#ifdef CONFIG_KVM_ARM_VGIC
-		vgic_present = true;
-#endif
-
 	/*
 	 * Init HYP architected timer support
 	 */
-- 
2.3.0

Re: [PATCH] KVM: arm/arm64: prefer IS_ENABLED to a static variable

[Christoffer Dall]

On Thu, Mar 05, 2015 at 12:26:06PM +0100, Paolo Bonzini wrote:
> IS_ENABLED gives compile-time checking and keeps the code clearer.
> 
> The one exception is inside kvm_vm_ioctl_check_extension, where
> the established idiom is to wrap the case labels with an #ifdef.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Thanks, I've applied this to my queue with a follow-up to remove config
options all together just like we have it on arm64.

I'll send out that patch based on yours and I've applied Eric's IRQFD
series on top of that.

Best,
-Christoffer