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From: Oliver Upton <oliver.upton@linux.dev>
To: kvmarm@lists.linux.dev
Cc: kvm@vger.kernel.org,
	Marc Zyngier <maz@kernel.org>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	linux-kernel@vger.kernel.org,
	Eric Auger <eric.auger@redhat.com>,
	Oliver Upton <oliver.upton@linux.dev>
Subject: [PATCH v4 07/10] KVM: arm64: vgic: Free LPI vgic_irq structs in an RCU-safe manner
Date: Wed, 21 Feb 2024 05:42:50 +0000
Message-ID: <20240221054253.3848076-8-oliver.upton@linux.dev>
In-Reply-To: <20240221054253.3848076-1-oliver.upton@linux.dev>
References: <20240221054253.3848076-1-oliver.upton@linux.dev>
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Free the vgic_irq structs in an RCU-safe manner to allow reads of the
LPI configuration data to happen in parallel with the release of LPIs.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kvm/vgic/vgic.c | 2 +-
 include/kvm/arm_vgic.h     | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index 15dbd17b3a9e..3fedc58e663a 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -125,7 +125,7 @@ void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq)
 	xa_erase(&dist->lpi_xa, irq->intid);
 	atomic_dec(&dist->lpi_count);
 
-	kfree(irq);
+	kfree_rcu(irq, rcu);
 }
 
 void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 71e9d719533b..47035946648e 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -117,6 +117,7 @@ struct irq_ops {
 
 struct vgic_irq {
 	raw_spinlock_t irq_lock;	/* Protects the content of the struct */
+	struct rcu_head rcu;
 	struct list_head ap_list;
 
 	struct kvm_vcpu *vcpu;		/* SGIs and PPIs: The VCPU
-- 
2.44.0.rc0.258.g7320e95886-goog