linux-kernel - [PATCH v3 05/10] KVM: arm64: vgic: Get rid of the LPI linked-list

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Message-ID: <20240216184153.2714504-6-oliver.upton@linux.dev>
Date: Fri, 16 Feb 2024 18:41:48 +0000
From: Oliver Upton <oliver.upton@...ux.dev>
To: kvmarm@...ts.linux.dev
Cc: kvm@...r.kernel.org,
	Marc Zyngier <maz@...nel.org>,
	James Morse <james.morse@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	linux-kernel@...r.kernel.org,
	Oliver Upton <oliver.upton@...ux.dev>
Subject: [PATCH v3 05/10] KVM: arm64: vgic: Get rid of the LPI linked-list

All readers of LPI configuration have been transitioned to use the LPI
xarray. Get rid of the linked-list altogether.

Signed-off-by: Oliver Upton <oliver.upton@...ux.dev>
---
 arch/arm64/kvm/vgic/vgic-init.c | 1 -
 arch/arm64/kvm/vgic/vgic-its.c  | 8 ++------
 arch/arm64/kvm/vgic/vgic.c      | 1 -
 include/kvm/arm_vgic.h          | 2 --
 4 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 411719053107..e25672d6e846 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -53,7 +53,6 @@ void kvm_vgic_early_init(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
 
-	INIT_LIST_HEAD(&dist->lpi_list_head);
 	INIT_LIST_HEAD(&dist->lpi_translation_cache);
 	raw_spin_lock_init(&dist->lpi_list_lock);
 	xa_init_flags(&dist->lpi_xa, XA_FLAGS_LOCK_IRQ);
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 9ce2edfadd11..0d1cfc776f47 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -58,7 +58,6 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
 		return ERR_PTR(ret);
 	}
 
-	INIT_LIST_HEAD(&irq->lpi_list);
 	INIT_LIST_HEAD(&irq->ap_list);
 	raw_spin_lock_init(&irq->irq_lock);
 
@@ -74,10 +73,8 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
 	 * There could be a race with another vgic_add_lpi(), so we need to
 	 * check that we don't add a second list entry with the same LPI.
 	 */
-	list_for_each_entry(oldirq, &dist->lpi_list_head, lpi_list) {
-		if (oldirq->intid != intid)
-			continue;
-
+	oldirq = xa_load(&dist->lpi_xa, intid);
+	if (oldirq) {
 		/* Someone was faster with adding this LPI, lets use that. */
 		kfree(irq);
 		irq = oldirq;
@@ -99,7 +96,6 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
 		goto out_unlock;
 	}
 
-	list_add_tail(&irq->lpi_list, &dist->lpi_list_head);
 	dist->lpi_list_count++;
 
 out_unlock:
diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index d90c42ff051d..e58ce68e325c 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -121,7 +121,6 @@ void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq)
 	if (!kref_put(&irq->refcount, vgic_irq_release))
 		return;
 
-	list_del(&irq->lpi_list);
 	xa_erase(&dist->lpi_xa, irq->intid);
 	dist->lpi_list_count--;
 
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 795b35656b54..aeff363e3ba6 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -117,7 +117,6 @@ struct irq_ops {
 
 struct vgic_irq {
 	raw_spinlock_t irq_lock;	/* Protects the content of the struct */
-	struct list_head lpi_list;	/* Used to link all LPIs together */
 	struct list_head ap_list;
 
 	struct kvm_vcpu *vcpu;		/* SGIs and PPIs: The VCPU
@@ -277,7 +276,6 @@ struct vgic_dist {
 	/* Protects the lpi_list and the count value below. */
 	raw_spinlock_t		lpi_list_lock;
 	struct xarray		lpi_xa;
-	struct list_head	lpi_list_head;
 	int			lpi_list_count;
 
 	/* LPI translation cache */
-- 
2.44.0.rc0.258.g7320e95886-goog