KVM: bit ops for deliver_bitmap

It's also convenient when we extend KVM supported vcpu number in the future.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 13 insertions, 11 deletions

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 3b5371299dd1..7c2cb2bd1199 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -203,7 +203,7 @@ void kvm_ioapic_get_delivery_bitmask(struct kvm_ioapic *ioapic, u8 dest,
 static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
 {
         union kvm_ioapic_redirect_entry entry = ioapic->redirtbl[irq];
-        unsigned long deliver_bitmask;
+        DECLARE_BITMAP(deliver_bitmask, KVM_MAX_VCPUS);
         struct kvm_vcpu *vcpu;
         int vcpu_id, r = -1;
 
@@ -213,22 +213,24 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
                      entry.fields.delivery_mode, entry.fields.vector,
                      entry.fields.trig_mode);
 
-        kvm_get_intr_delivery_bitmask(ioapic, &entry, &deliver_bitmask);
-        if (!deliver_bitmask) {
-                ioapic_debug("no target on destination\n");
-                return 0;
-        }
+        bitmap_zero(deliver_bitmask, KVM_MAX_VCPUS);
 
         /* Always delivery PIT interrupt to vcpu 0 */
 #ifdef CONFIG_X86
         if (irq == 0)
-                deliver_bitmask = 1;
+                __set_bit(0, deliver_bitmask);
+        else
 #endif
+                kvm_get_intr_delivery_bitmask(ioapic, &entry, deliver_bitmask);
+
+        if (find_first_bit(deliver_bitmask, KVM_MAX_VCPUS) >= KVM_MAX_VCPUS) {
+                ioapic_debug("no target on destination\n");
+                return 0;
+        }
 
-        for (vcpu_id = 0; deliver_bitmask != 0; vcpu_id++) {
-                if (!(deliver_bitmask & (1 << vcpu_id)))
-                        continue;
-                deliver_bitmask &= ~(1 << vcpu_id);
+        while ((vcpu_id = find_first_bit(deliver_bitmask, KVM_MAX_VCPUS))
+                        < KVM_MAX_VCPUS) {
+                __clear_bit(vcpu_id, deliver_bitmask);
                 vcpu = ioapic->kvm->vcpus[vcpu_id];
                 if (vcpu) {
                         if (entry.fields.delivery_mode ==