Re: [PATCH v4 08/48] KVM: arm64: gic-v5: Add VPE doorbell domain

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Allocated doorbell IRQs and their associated request handlers are leaked during VM teardown, exhausting IRQ descriptors and triggering a kernel warning.
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--- Patch [8]: [PATCH v4 08/48] KVM: arm64: gic-v5: Add VPE doorbell domain ---
commit 3bd242f19027d5c3f4f9f1ea26d5e37b8f153bd4
Author: Sascha Bischoff <Sascha.Bischoff@arm.com>

KVM: arm64: gic-v5: Add VPE doorbell domain

This commit adds support for a per-VM VPE doorbell irq domain in GICv5.
It allocates one doorbell per VPE and stores the doorbell base in the VM's
state for use with IRS commands and wakeups.

> diff --git a/arch/arm64/kvm/vgic/vgic-v5.c b/arch/arm64/kvm/vgic/vgic-v5.c
> index 3f7b132110114..ebd7c3ede975f 100644
> --- a/arch/arm64/kvm/vgic/vgic-v5.c
> +++ b/arch/arm64/kvm/vgic/vgic-v5.c

[ ... ]

> +static void vgic_v5_teardown_per_vm_domain(struct vgic_v5_vm *vm)
> +{
> +	if (!vm->domain)
> +		return;
> +

[Severity: High]
Does this code leak the allocated doorbell IRQs and their request handlers?

During initialization, vgic_v5_create_per_vm_domain() allocates IRQs via
irq_domain_alloc_irqs(), and vgic_v5_init() requests them via request_irq().

Should free_irq() and irq_domain_free_irqs() be called before tearing down
the domain? Removing a domain that still has allocated IRQs can trigger a
warning in the core IRQ subsystem, and repeatedly creating and destroying
VMs could eventually exhaust the IRQ descriptor space.

> +	irq_domain_remove(vm->domain);
> +	irq_domain_free_fwnode(vm->fwnode);
> +	vm->domain = NULL;
> +	vm->fwnode = NULL;
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260724104819.1296803-1-sascha.bischoff@arm.com?part=8