[PATCH 05/18] KVM: arm64: vgic: Constify struct irq_ops usage

Marc Zyngier
2026-04-15T11:56:32Z

vgic-v5 has introduced much more prevalent usage of the struct
irq_ops mechanism.

In the process, it becomes evident that suffers from two related
problems:

- it contains flags, rather than only callbacks
- it is mutable, because we need to update the above flags

Swap the flags for a helper retrieving the flags, and make all
irq_ops const, something that is slightly satisfying.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/arch_timer.c | 14 +++++++++-----
arch/arm64/kvm/vgic/vgic-v5.c | 2 +-
arch/arm64/kvm/vgic/vgic.c | 2 +-
include/kvm/arm_vgic.h | 9 +++++----
4 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index cbea4d9ee9552..f003df76fdda7 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -52,11 +52,17 @@ static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
enum kvm_arch_timer_regs treg);
static bool kvm_arch_timer_get_input_level(int vintid);

-static struct irq_ops arch_timer_irq_ops = {
+static unsigned long kvm_arch_timer_get_irq_flags(void)
+{
+ return kvm_vgic_global_state.no_hw_deactivation ? VGIC_IRQ_SW_RESAMPLE : 0;
+}
+
+static const struct irq_ops arch_timer_irq_ops = {
+ .get_flags = kvm_arch_timer_get_irq_flags,
.get_input_level = kvm_arch_timer_get_input_level,
};

-static struct irq_ops arch_timer_irq_ops_vgic_v5 = {
+static const struct irq_ops arch_timer_irq_ops_vgic_v5 = {
.get_input_level = kvm_arch_timer_get_input_level,
.queue_irq_unlock = vgic_v5_ppi_queue_irq_unlock,
.set_direct_injection = vgic_v5_set_ppi_dvi,
@@ -1392,8 +1398,6 @@ static int kvm_irq_init(struct arch_timer_kvm_info *info)
return -ENOMEM;
}

- if (kvm_vgic_global_state.no_hw_deactivation)
- arch_timer_irq_ops.flags |= VGIC_IRQ_SW_RESAMPLE;
WARN_ON(irq_domain_push_irq(domain, host_vtimer_irq,
(void *)TIMER_VTIMER));
}
@@ -1591,8 +1595,8 @@ static bool kvm_arch_timer_get_input_level(int vintid)
int kvm_timer_enable(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = vcpu_timer(vcpu);
+ const struct irq_ops *ops;
struct timer_map map;
- struct irq_ops *ops;
int ret;

if (timer->enabled)
diff --git a/arch/arm64/kvm/vgic/vgic-v5.c b/arch/arm64/kvm/vgic/vgic-v5.c
index 0101ec3f55283..757484d2493b2 100644
--- a/arch/arm64/kvm/vgic/vgic-v5.c
+++ b/arch/arm64/kvm/vgic/vgic-v5.c
@@ -285,7 +285,7 @@ void vgic_v5_set_ppi_dvi(struct kvm_vcpu *vcpu, struct vgic_irq *irq, bool dvi)
__assign_bit(ppi, cpu_if->vgic_ppi_dvir, dvi);
}

-static struct irq_ops vgic_v5_ppi_irq_ops = {
+static const struct irq_ops vgic_v5_ppi_irq_ops = {
.queue_irq_unlock = vgic_v5_ppi_queue_irq_unlock,
.set_direct_injection = vgic_v5_set_ppi_dvi,
};
diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index 1e9fe8764584d..3ac6d49bc4876 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -573,7 +573,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
}

void kvm_vgic_set_irq_ops(struct kvm_vcpu *vcpu, u32 vintid,
- struct irq_ops *ops)
+ const struct irq_ops *ops)
{
struct vgic_irq *irq = vgic_get_vcpu_irq(vcpu, vintid);

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index ea793479ab254..fe49fb56dc3c9 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -205,7 +205,7 @@ struct vgic_irq;
*/
struct irq_ops {
/* Per interrupt flags for special-cased interrupts */
- unsigned long flags;
+ unsigned long (*get_flags)(void);

#define VGIC_IRQ_SW_RESAMPLE BIT(0) /* Clear the active state for resampling */

@@ -271,7 +271,7 @@ struct vgic_irq {
u8 priority;
u8 group; /* 0 == group 0, 1 == group 1 */

- struct irq_ops *ops;
+ const struct irq_ops *ops;

void *owner; /* Opaque pointer to reserve an interrupt
for in-kernel devices. */
@@ -279,7 +279,8 @@ struct vgic_irq {

static inline bool vgic_irq_needs_resampling(struct vgic_irq *irq)
{
- return irq->ops && (irq->ops->flags & VGIC_IRQ_SW_RESAMPLE);
+ return irq->ops && irq->ops->get_flags &&
+ (irq->ops->get_flags() & VGIC_IRQ_SW_RESAMPLE);
}

struct vgic_register_region;
@@ -557,7 +558,7 @@ void kvm_vgic_init_cpu_hardware(void);
int kvm_vgic_inject_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
unsigned int intid, bool level, void *owner);
void kvm_vgic_set_irq_ops(struct kvm_vcpu *vcpu, u32 vintid,
- struct irq_ops *ops);
+ const struct irq_ops *ops);
void kvm_vgic_clear_irq_ops(struct kvm_vcpu *vcpu, u32 vintid);
int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
u32 vintid);
--
2.47.3