KVM: ia64: dynamic nr online cpus

Account for number of online cpus and use that in loops iterating over
the list of vpus instead of scanning the full array unconditionally.
This patch is a building block to facilitate allowing to bump up
the size of MAX_VCPUS significantly.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by : Xiantao Zhang  <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

3 files changed, 18 insertions, 9 deletions

diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 46f8b0eb5684..4542651e6acb 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -157,10 +157,10 @@ struct kvm_vm_data {
         struct kvm_vcpu_data vcpu_data[KVM_MAX_VCPUS];
 };
 
-#define VCPU_BASE(n)    KVM_VM_DATA_BASE + \
-                                offsetof(struct kvm_vm_data, vcpu_data[n])
-#define VM_BASE         KVM_VM_DATA_BASE + \
-                                offsetof(struct kvm_vm_data, kvm_vm_struct)
+#define VCPU_BASE(n)    (KVM_VM_DATA_BASE + \
+                                offsetof(struct kvm_vm_data, vcpu_data[n]))
+#define KVM_VM_BASE     (KVM_VM_DATA_BASE + \
+                                offsetof(struct kvm_vm_data, kvm_vm_struct))
 #define KVM_MEM_DIRTY_LOG_BASE  KVM_VM_DATA_BASE + \
                                 offsetof(struct kvm_vm_data, kvm_mem_dirty_log)
 
@@ -464,6 +464,8 @@ struct kvm_arch {
         unsigned long   metaphysical_rr4;
         unsigned long   vmm_init_rr;
 
+        int             online_vcpus;
+
         struct kvm_ioapic *vioapic;
         struct kvm_vm_stat stat;
         struct kvm_sal_data rdv_sal_data;
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index dbf527a57341..9c77e3939e97 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -314,7 +314,7 @@ static struct kvm_vcpu *lid_to_vcpu(struct kvm *kvm, unsigned long id,
         union ia64_lid lid;
         int i;
 
-        for (i = 0; i < KVM_MAX_VCPUS; i++) {
+        for (i = 0; i < kvm->arch.online_vcpus; i++) {
                 if (kvm->vcpus[i]) {
                         lid.val = VCPU_LID(kvm->vcpus[i]);
                         if (lid.id == id && lid.eid == eid)
@@ -388,7 +388,7 @@ 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_MAX_VCPUS; i++) {
+        for (i = 0; i < kvm->arch.online_vcpus; i++) {
                 if (!kvm->vcpus[i] || kvm->vcpus[i]->arch.mp_state ==
                                                 KVM_MP_STATE_UNINITIALIZED ||
                                         vcpu == kvm->vcpus[i])
@@ -788,6 +788,8 @@ struct  kvm *kvm_arch_create_vm(void)
                 return ERR_PTR(-ENOMEM);
         kvm_init_vm(kvm);
 
+        kvm->arch.online_vcpus = 0;
+
         return kvm;
 
 }
@@ -1154,7 +1156,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 
                 /*Initialize itc offset for vcpus*/
                 itc_offset = 0UL - ia64_getreg(_IA64_REG_AR_ITC);
-                for (i = 0; i < KVM_MAX_VCPUS; i++) {
+                for (i = 0; i < kvm->arch.online_vcpus; i++) {
                         v = (struct kvm_vcpu *)((char *)vcpu +
                                         sizeof(struct kvm_vcpu_data) * i);
                         v->arch.itc_offset = itc_offset;
@@ -1288,6 +1290,8 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
                 goto fail;
         }
 
+        kvm->arch.online_vcpus++;
+
         return vcpu;
 fail:
         return ERR_PTR(r);
@@ -1828,7 +1832,7 @@ struct kvm_vcpu *kvm_get_lowest_prio_vcpu(struct kvm *kvm, u8 vector,
         struct kvm_vcpu *lvcpu = kvm->vcpus[0];
         int i;
 
-        for (i = 1; i < KVM_MAX_VCPUS; i++) {
+        for (i = 1; i < kvm->arch.online_vcpus; i++) {
                 if (!kvm->vcpus[i])
                         continue;
                 if (lvcpu->arch.xtp > kvm->vcpus[i]->arch.xtp)
diff --git a/arch/ia64/kvm/vcpu.c b/arch/ia64/kvm/vcpu.c
index 4d8be4c252fa..d4d280505878 100644
--- a/arch/ia64/kvm/vcpu.c
+++ b/arch/ia64/kvm/vcpu.c
@@ -807,12 +807,15 @@ static inline void vcpu_set_itm(struct kvm_vcpu *vcpu, u64 val);
 static void vcpu_set_itc(struct kvm_vcpu *vcpu, u64 val)
 {
         struct kvm_vcpu *v;
+        struct kvm *kvm;
         int i;
         long itc_offset = val - ia64_getreg(_IA64_REG_AR_ITC);
         unsigned long vitv = VCPU(vcpu, itv);
 
+        kvm = (struct kvm *)KVM_VM_BASE;
+
         if (vcpu->vcpu_id == 0) {
-                for (i = 0; i < KVM_MAX_VCPUS; i++) {
+                for (i = 0; i < kvm->arch.online_vcpus; i++) {
                         v = (struct kvm_vcpu *)((char *)vcpu +
                                         sizeof(struct kvm_vcpu_data) * i);
                         VMX(v, itc_offset) = itc_offset;