[PATCH 1/1] KVM: Correct deliver_bitmask in kvm_get_intr_delivery_bitmask

[Sheng Yang <sheng@linux.intel.com>]

1. deliver_bitmask is a bitmap rather than a unsigned long intereger.
2. Lowest priority target bitmap wrong calculated by mistake.
3. Prevent potential NULL reference.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
 virt/kvm/irq_comm.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index d165e05..8e1869d 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -54,8 +54,12 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic *ioapic,
 					deliver_bitmask);
 	switch (entry->fields.delivery_mode) {
 	case IOAPIC_LOWEST_PRIORITY:
+		/* Select one in deliver_bitmask */
 		vcpu = kvm_get_lowest_prio_vcpu(ioapic->kvm,
 				entry->fields.vector, deliver_bitmask);
+		bitmap_zero(deliver_bitmask, KVM_MAX_VCPUS);
+		if (!vcpu)
+			return;
 		__set_bit(vcpu->vcpu_id, deliver_bitmask);
 		break;
 	case IOAPIC_FIXED:
@@ -65,7 +69,7 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic *ioapic,
 		if (printk_ratelimit())
 			printk(KERN_INFO "kvm: unsupported delivery mode %d\n",
 				entry->fields.delivery_mode);
-		*deliver_bitmask = 0;
+		bitmap_zero(deliver_bitmask, KVM_MAX_VCPUS);
 	}
 }
 
-- 
1.5.4.5