[PATCH v1 04/11] KVM: x86: use u16 for logical VCPU mask in lapic

Radim Krčmář
2016-06-30T20:57:43Z

for_all_bits() never were type safe, so we don't lose safety when
casting u16 * to unsigned long * and u16 is the size we want to avoid
mishaps when sending the pointer to functions that operate only on 16
bits.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
arch/x86/kvm/lapic.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index eed5af46e619..4296bb7353ff 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -694,7 +694,7 @@ static void kvm_apic_disabled_lapic_found(struct kvm *kvm)
*/
static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm, struct kvm_lapic *src,
struct kvm_lapic_irq *irq, struct kvm_apic_map *map,
- struct kvm_lapic ***dst, unsigned long *bitmap)
+ struct kvm_lapic ***dst, u16 *bitmap)
{
int i, lowest;
bool x2apic_ipi;
@@ -723,9 +723,7 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm, struct kvm_lapic
return true;
}

- *bitmap = 0;
- if (!kvm_apic_map_get_logical_dest(map, irq->dest_id, dst,
- (u16 *)bitmap))
+ if (!kvm_apic_map_get_logical_dest(map, irq->dest_id, dst, bitmap))
return false;

if (!kvm_lowest_prio_delivery(irq))
@@ -733,7 +731,7 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm, struct kvm_lapic

if (!kvm_vector_hashing_enabled()) {
lowest = -1;
- for_each_set_bit(i, bitmap, 16) {
+ for_each_set_bit(i, (unsigned long *)bitmap, 16) {
if (!(*dst)[i])
continue;
if (lowest < 0)
@@ -747,7 +745,7 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm, struct kvm_lapic
return true;

lowest = kvm_vector_to_index(irq->vector, hweight16(*bitmap),
- bitmap, 16);
+ (unsigned long *)bitmap, 16);

if (!(*dst)[lowest]) {
kvm_apic_disabled_lapic_found(kvm);
@@ -765,7 +763,7 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
struct kvm_lapic_irq *irq, int *r, struct dest_map *dest_map)
{
struct kvm_apic_map *map;
- unsigned long bitmap;
+ u16 bitmap;
struct kvm_lapic **dst = NULL;
int i;
bool ret;
@@ -782,7 +780,7 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,

ret = kvm_apic_map_get_dest_lapic(kvm, src, irq, map, &dst, &bitmap);
if (ret)
- for_each_set_bit(i, &bitmap, 16) {
+ for_each_set_bit(i, (unsigned long *)&bitmap, 16) {
if (!dst[i])
continue;
if (*r < 0)
@@ -812,7 +810,7 @@ bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
struct kvm_vcpu **dest_vcpu)
{
struct kvm_apic_map *map;
- unsigned long bitmap;
+ u16 bitmap;
struct kvm_lapic **dst = NULL;
bool ret = false;

@@ -824,7 +822,7 @@ bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,

if (kvm_apic_map_get_dest_lapic(kvm, NULL, irq, map, &dst, &bitmap) &&
hweight16(bitmap) == 1) {
- unsigned long i = find_first_bit(&bitmap, 16);
+ unsigned long i = find_first_bit((unsigned long *)&bitmap, 16);

if (dst[i]) {
*dest_vcpu = dst[i]->vcpu;
--
2.9.0