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KVM: x86: add kvm_apic_map_get_dest_lapic
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kvm_irq_delivery_to_apic_fast and kvm_intr_is_single_vcpu_fast both
compute the interrupt destination.  Factor the code.

'struct kvm_lapic **dst = NULL' had to be added to silence GCC.
GCC might complain about potential NULL access in the future, because it
missed conditions that avoided uninitialized uses of dst.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Radim Krčmář authored and Paolo Bonzini committed Jul 14, 2016
1 parent 757883d commit 64aa47b
Showing 1 changed file with 98 additions and 132 deletions.
230 changes: 98 additions & 132 deletions arch/x86/kvm/lapic.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -671,102 +671,120 @@ static void kvm_apic_disabled_lapic_found(struct kvm *kvm)
}
}

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 = 1;
struct kvm_lapic **dst;
int i;
bool ret, x2apic_ipi;
/* Return true if the interrupt can be handled by using *bitmap as index mask
* for valid destinations in *dst array.
* Return false if kvm_apic_map_get_dest_lapic did nothing useful.
* Note: we may have zero kvm_lapic destinations when we return true, which
* means that the interrupt should be dropped. In this case, *bitmap would be
* zero and *dst undefined.
*/
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)
{
int i, lowest;
bool x2apic_ipi;
u16 cid;

if (irq->shorthand == APIC_DEST_SELF && src) {
*dst = src;
*bitmap = 1;
return true;
} else if (irq->shorthand)
return false;

*r = -1;
x2apic_ipi = src && *src && apic_x2apic_mode(*src);
if (irq->dest_id == (x2apic_ipi ? X2APIC_BROADCAST : APIC_BROADCAST))
return false;

if (irq->shorthand == APIC_DEST_SELF) {
*r = kvm_apic_set_irq(src->vcpu, irq, dest_map);
if (!map)
return false;

if (irq->dest_mode == APIC_DEST_PHYSICAL) {
if (irq->dest_id >= ARRAY_SIZE(map->phys_map)) {
*bitmap = 0;
} else {
*dst = &map->phys_map[irq->dest_id];
*bitmap = 1;
}
return true;
}

if (irq->shorthand)
if (!kvm_apic_logical_map_valid(map))
return false;

x2apic_ipi = src && apic_x2apic_mode(src);
if (irq->dest_id == (x2apic_ipi ? X2APIC_BROADCAST : APIC_BROADCAST))
return false;

ret = true;
rcu_read_lock();
map = rcu_dereference(kvm->arch.apic_map);
apic_logical_id(map, irq->dest_id, &cid, (u16 *)bitmap);

if (!map) {
ret = false;
goto out;
if (cid >= ARRAY_SIZE(map->logical_map)) {
*bitmap = 0;
return true;
}

if (irq->dest_mode == APIC_DEST_PHYSICAL) {
if (irq->dest_id >= ARRAY_SIZE(map->phys_map))
goto out;
*dst = map->logical_map[cid];

dst = &map->phys_map[irq->dest_id];
} else {
u16 cid;
if (!kvm_lowest_prio_delivery(irq))
return true;

if (!kvm_apic_logical_map_valid(map)) {
ret = false;
goto out;
if (!kvm_vector_hashing_enabled()) {
lowest = -1;
for_each_set_bit(i, bitmap, 16) {
if (!(*dst)[i])
continue;
if (lowest < 0)
lowest = i;
else if (kvm_apic_compare_prio((*dst)[i]->vcpu,
(*dst)[lowest]->vcpu) < 0)
lowest = i;
}
} else {
if (!*bitmap)
return true;

apic_logical_id(map, irq->dest_id, &cid, (u16 *)&bitmap);
lowest = kvm_vector_to_index(irq->vector, hweight16(*bitmap),
bitmap, 16);

if (cid >= ARRAY_SIZE(map->logical_map))
goto out;
if (!(*dst)[lowest]) {
kvm_apic_disabled_lapic_found(kvm);
*bitmap = 0;
return true;
}
}

dst = map->logical_map[cid];
*bitmap = (lowest >= 0) ? 1 << lowest : 0;

if (!kvm_lowest_prio_delivery(irq))
goto set_irq;
return true;
}

if (!kvm_vector_hashing_enabled()) {
int l = -1;
for_each_set_bit(i, &bitmap, 16) {
if (!dst[i])
continue;
if (l < 0)
l = i;
else if (kvm_apic_compare_prio(dst[i]->vcpu,
dst[l]->vcpu) < 0)
l = i;
}
bitmap = (l >= 0) ? 1 << l : 0;
} else {
int idx;
unsigned int dest_vcpus;
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;
struct kvm_lapic **dst = NULL;
int i;
bool ret;

dest_vcpus = hweight16(bitmap);
if (dest_vcpus == 0)
goto out;
*r = -1;

idx = kvm_vector_to_index(irq->vector,
dest_vcpus, &bitmap, 16);
if (irq->shorthand == APIC_DEST_SELF) {
*r = kvm_apic_set_irq(src->vcpu, irq, dest_map);
return true;
}

if (!dst[idx]) {
kvm_apic_disabled_lapic_found(kvm);
goto out;
}
rcu_read_lock();
map = rcu_dereference(kvm->arch.apic_map);

bitmap = (idx >= 0) ? 1 << idx : 0;
ret = kvm_apic_map_get_dest_lapic(kvm, &src, irq, map, &dst, &bitmap);
if (ret)
for_each_set_bit(i, &bitmap, 16) {
if (!dst[i])
continue;
if (*r < 0)
*r = 0;
*r += kvm_apic_set_irq(dst[i]->vcpu, irq, dest_map);
}
}

set_irq:
for_each_set_bit(i, &bitmap, 16) {
if (!dst[i])
continue;
if (*r < 0)
*r = 0;
*r += kvm_apic_set_irq(dst[i]->vcpu, irq, dest_map);
}
out:
rcu_read_unlock();
return ret;
}
Expand All @@ -789,78 +807,26 @@ 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;
struct kvm_lapic **dst = NULL;
bool ret = false;
struct kvm_lapic *dst = NULL;

if (irq->shorthand)
return false;

rcu_read_lock();
map = rcu_dereference(kvm->arch.apic_map);

if (!map)
goto out;

if (irq->dest_mode == APIC_DEST_PHYSICAL) {
if (irq->dest_id == 0xFF)
goto out;

if (irq->dest_id >= ARRAY_SIZE(map->phys_map))
goto out;

dst = map->phys_map[irq->dest_id];
if (dst && kvm_apic_present(dst->vcpu))
*dest_vcpu = dst->vcpu;
else
goto out;
} else {
u16 cid;
unsigned long bitmap = 1;
int i, r = 0;

if (!kvm_apic_logical_map_valid(map))
goto out;

apic_logical_id(map, irq->dest_id, &cid, (u16 *)&bitmap);

if (cid >= ARRAY_SIZE(map->logical_map))
goto out;

if (kvm_vector_hashing_enabled() &&
kvm_lowest_prio_delivery(irq)) {
int idx;
unsigned int dest_vcpus;
if (kvm_apic_map_get_dest_lapic(kvm, NULL, irq, map, &dst, &bitmap) &&
hweight16(bitmap) == 1) {
unsigned long i = find_first_bit(&bitmap, 16);

dest_vcpus = hweight16(bitmap);
if (dest_vcpus == 0)
goto out;

idx = kvm_vector_to_index(irq->vector, dest_vcpus,
&bitmap, 16);

dst = map->logical_map[cid][idx];
if (!dst) {
kvm_apic_disabled_lapic_found(kvm);
goto out;
}

*dest_vcpu = dst->vcpu;
} else {
for_each_set_bit(i, &bitmap, 16) {
dst = map->logical_map[cid][i];
if (++r == 2)
goto out;
}

if (dst && kvm_apic_present(dst->vcpu))
*dest_vcpu = dst->vcpu;
else
goto out;
if (dst[i]) {
*dest_vcpu = dst[i]->vcpu;
ret = true;
}
}

ret = true;
out:
rcu_read_unlock();
return ret;
}
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