KVM: Break dependency between vcpu index in vcpus array and vcpu_id.

Archs are free to use vcpu_id as they see fit. For x86 it is used as
vcpu's apic id. New ioctl is added to configure boot vcpu id that was
assumed to be 0 till now.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/ia64/include/asm/kvm_host.h

@@ -465,7 +465,6 @@ struct kvm_arch {
 	unsigned long	metaphysical_rr4;
 	unsigned long	vmm_init_rr;
 
-	int		online_vcpus;
 	int		is_sn2;
 
 	struct kvm_ioapic *vioapic;

arch/ia64/kvm/Kconfig

@@ -25,6 +25,7 @@ config KVM
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
 	select HAVE_KVM_IRQCHIP
+	select KVM_APIC_ARCHITECTURE
 	---help---
 	  Support hosting fully virtualized guest machines using hardware
 	  virtualization extensions.  You will need a fairly recent

arch/ia64/kvm/kvm-ia64.c

@@ -338,7 +338,7 @@ static struct kvm_vcpu *lid_to_vcpu(struct kvm *kvm, unsigned long id,
 	union ia64_lid lid;
 	int i;
 
-	for (i = 0; i < kvm->arch.online_vcpus; i++) {
+	for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
 		if (kvm->vcpus[i]) {
 			lid.val = VCPU_LID(kvm->vcpus[i]);
 			if (lid.id == id && lid.eid == eid)
@@ -412,7 +412,7 @@ static int handle_global_purge(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 
 	call_data.ptc_g_data = p->u.ptc_g_data;
 
-	for (i = 0; i < kvm->arch.online_vcpus; i++) {
+	for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
 		if (!kvm->vcpus[i] || kvm->vcpus[i]->arch.mp_state ==
 						KVM_MP_STATE_UNINITIALIZED ||
 					vcpu == kvm->vcpus[i])
@@ -852,8 +852,6 @@ struct  kvm *kvm_arch_create_vm(void)
 
 	kvm_init_vm(kvm);
 
-	kvm->arch.online_vcpus = 0;
-
 	return kvm;
 
 }
@@ -1356,8 +1354,6 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
 		goto fail;
 	}
 
-	kvm->arch.online_vcpus++;
-
 	return vcpu;
 fail:
 	return ERR_PTR(r);

arch/ia64/kvm/vcpu.c

@@ -831,7 +831,7 @@ static void vcpu_set_itc(struct kvm_vcpu *vcpu, u64 val)
 	kvm = (struct kvm *)KVM_VM_BASE;
 
 	if (kvm_vcpu_is_bsp(vcpu)) {
-		for (i = 0; i < kvm->arch.online_vcpus; i++) {
+		for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
 			v = (struct kvm_vcpu *)((char *)vcpu +
 					sizeof(struct kvm_vcpu_data) * i);
 			VMX(v, itc_offset) = itc_offset;