KVM: arm64: vgic: Free LPI vgic_irq structs in an RCU-safe manner

oupton · oupton · commit a5c7f011cb58 · 2024-02-23T21:46:02.000Z
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. Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240221054253.3848076-8-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
diff --git 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
@@ -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

Original file line number	Diff line number	Diff line change
`@@ -125,7 +125,7 @@ void __vgic_put_lpi_locked(struct kvm kvm, struct vgic_irq irq)`
`125`	`125`	`xa_erase(&dist->lpi_xa, irq->intid);`
`126`	`126`	`atomic_dec(&dist->lpi_count);`
`127`	`127`
`128`		`- kfree(irq);`
	`128`	`+ kfree_rcu(irq, rcu);`
`129`	`129`	`}`
`130`	`130`
`131`	`131`	`void vgic_put_irq(struct kvm kvm, struct vgic_irq irq)`