Commit fe06a0c0 authored by Yury Norov's avatar Yury Norov
Browse files

KVM: x86: replace bitmap_weight with bitmap_empty where appropriate 



In some places kvm/hyperv.c code calls bitmap_weight() to check if any bit
of a given bitmap is set. It's better to use bitmap_empty() in that case
because bitmap_empty() stops traversing the bitmap as soon as it finds
first set bit, while bitmap_weight() counts all bits unconditionally.

Signed-off-by: default avatarYury Norov <yury.norov@gmail.com>
Reviewed-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent 64b87c1a

arch/x86/kvm/hyperv.c

+4 −4
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ static void synic_update_vector(struct kvm_vcpu_hv_synic *synic, 
{

	struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic);

	struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);

	int auto_eoi_old, auto_eoi_new;

	bool auto_eoi_old, auto_eoi_new;



	if (vector < HV_SYNIC_FIRST_VALID_VECTOR)

		return;
@@ -100,16 +100,16 @@ static void synic_update_vector(struct kvm_vcpu_hv_synic *synic, 
	else

		__clear_bit(vector, synic->vec_bitmap);



	auto_eoi_old = bitmap_weight(synic->auto_eoi_bitmap, 256);

	auto_eoi_old = !bitmap_empty(synic->auto_eoi_bitmap, 256);



	if (synic_has_vector_auto_eoi(synic, vector))

		__set_bit(vector, synic->auto_eoi_bitmap);

	else

		__clear_bit(vector, synic->auto_eoi_bitmap);



	auto_eoi_new = bitmap_weight(synic->auto_eoi_bitmap, 256);

	auto_eoi_new = !bitmap_empty(synic->auto_eoi_bitmap, 256);



	if (!!auto_eoi_old == !!auto_eoi_new)

	if (auto_eoi_old == auto_eoi_new)

		return;



	if (!enable_apicv)