[PATCH 14/15] KVM: arm64: vgic-its: Treat the LPI translation cache as an rculist

Oliver Upton
2024-01-24T20:49:50Z

Convert the LPI translation cache to an rculist such that readers can
walk it while only holding the RCU read lock.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/vgic/vgic-its.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 79b35fdaa1cd..1670b452c682 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -566,7 +566,7 @@ static struct vgic_irq *__vgic_its_check_cache(struct vgic_dist *dist,
{
struct vgic_translation_cache_entry *cte;

- list_for_each_entry(cte, &dist->lpi_translation_cache, entry) {
+ list_for_each_entry_rcu(cte, &dist->lpi_translation_cache, entry) {
/*
* If we hit a NULL entry, there is nothing after this
* point.
@@ -671,7 +671,7 @@ static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its,
goto out;
}

- list_del(&victim->entry);
+ list_del_rcu(&victim->entry);
dist->lpi_cache_count--;
} else {
victim = NULL;
@@ -690,7 +690,8 @@ static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its,
rcu_assign_pointer(new->irq, irq);

/* Move the new translation to the head of the list */
- list_add(&new->entry, &dist->lpi_translation_cache);
+ list_add_rcu(&new->entry, &dist->lpi_translation_cache);
+ dist->lpi_cache_count++;

out:
rcu_read_unlock();
@@ -704,6 +705,7 @@ static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its,
if (victim && victim->irq)
vgic_put_irq(kvm, victim->irq);

+ synchronize_rcu();
kfree(victim);
}

--
2.43.0.429.g432eaa2c6b-goog