KVM: fix irq_source_id size verification

find_first_zero_bit works with bit numbers, not bytes.

Fixes

https://sourceforge.net/tracker/?func=detail&aid=2847560&group_id=180599&atid=893831

Reported-by: "Xu, Jiajun" <jiajun.xu@intel.com>
Cc: stable@kernel.org
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 00c68d298579..0d454d352717 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -215,10 +215,9 @@ int kvm_request_irq_source_id(struct kvm *kvm)
         int irq_source_id;
 
         mutex_lock(&kvm->irq_lock);
-        irq_source_id = find_first_zero_bit(bitmap,
-                                sizeof(kvm->arch.irq_sources_bitmap));
+        irq_source_id = find_first_zero_bit(bitmap, BITS_PER_LONG);
 
-        if (irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) {
+        if (irq_source_id >= BITS_PER_LONG) {
                 printk(KERN_WARNING "kvm: exhaust allocatable IRQ sources!\n");
                 irq_source_id = -EFAULT;
                 goto unlock;
@@ -240,7 +239,7 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
 
         mutex_lock(&kvm->irq_lock);
         if (irq_source_id < 0 ||
-            irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) {
+            irq_source_id >= BITS_PER_LONG) {
                 printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
                 goto unlock;
         }