KVM: arm64: Constify kvm_io_gic_ops

The only usage of kvm_io_gic_ops is to make a comparison with its
address and to pass its address to kvm_iodevice_init() which takes a
pointer to const kvm_io_device_ops as input. Make it const to allow the
compiler to put it in read-only memory.
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211204213518.83642-1-rikard.falkeborn@gmail.com

arch/arm64/kvm/vgic/vgic-mmio.c

@@ -1050,7 +1050,7 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 	return 0;
 }
 
-struct kvm_io_device_ops kvm_io_gic_ops = {
+const struct kvm_io_device_ops kvm_io_gic_ops = {
 	.read = dispatch_mmio_read,
 	.write = dispatch_mmio_write,
 };

arch/arm64/kvm/vgic/vgic-mmio.h

@@ -34,7 +34,7 @@ struct vgic_register_region {
 	};
 };
 
-extern struct kvm_io_device_ops kvm_io_gic_ops;
+extern const struct kvm_io_device_ops kvm_io_gic_ops;
 
 #define VGIC_ACCESS_8bit	1
 #define VGIC_ACCESS_32bit	2