[PATCH v10 12/43] KVM: arm64: vgic: Provide helper for number of list registers

Steven Price
2025-08-20T14:58:05Z

Currently the number of list registers available is stored in a global
(kvm_vgic_global_state.nr_lr). With Arm CCA the RMM is permitted to
reserve list registers for its own use and so the number of available
list registers can be fewer for a realm VM. Provide a wrapper function
to fetch the global in preparation for restricting nr_lr when dealing
with a realm VM.

Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
New patch for v6
---
arch/arm64/kvm/vgic/vgic.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index f5148b38120a..b70bff9a624f 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -21,6 +21,11 @@ struct vgic_global kvm_vgic_global_state __ro_after_init = {
.gicv3_cpuif = STATIC_KEY_FALSE_INIT,
};

+static inline int kvm_vcpu_vgic_nr_lr(struct kvm_vcpu *vcpu)
+{
+ return kvm_vgic_global_state.nr_lr;
+}
+
/*
* Locking order is always:
* kvm->lock (mutex)
@@ -802,7 +807,7 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
lockdep_assert_held(&vgic_cpu->ap_list_lock);

count = compute_ap_list_depth(vcpu, &multi_sgi);
- if (count > kvm_vgic_global_state.nr_lr || multi_sgi)
+ if (count > kvm_vcpu_vgic_nr_lr(vcpu) || multi_sgi)
vgic_sort_ap_list(vcpu);

count = 0;
@@ -831,7 +836,7 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)

raw_spin_unlock(&irq->irq_lock);

- if (count == kvm_vgic_global_state.nr_lr) {
+ if (count == kvm_vcpu_vgic_nr_lr(vcpu)) {
if (!list_is_last(&irq->ap_list,
&vgic_cpu->ap_list_head))
vgic_set_underflow(vcpu);
@@ -840,7 +845,7 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
}

/* Nuke remaining LRs */
- for (i = count ; i < kvm_vgic_global_state.nr_lr; i++)
+ for (i = count; i < kvm_vcpu_vgic_nr_lr(vcpu); i++)
vgic_clear_lr(vcpu, i);

if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
--
2.43.0