Re: [Xen-devel] [PATCH v2 38/45] ARM: new VGIC: Implement arch_move_irqs()

[Julien Grall <julien.grall@xxxxxxx>]

Hi Andre,

On 03/15/2018 08:30 PM, Andre Przywara wrote:
> When a VCPU moves to another CPU, we need to adjust the target affinity
> of any hardware mapped vIRQs, to observe our "physical-follows-virtual"
> policy.
> Implement arch_move_irqs() to adjust the physical affinity of all hardware
> mapped vIRQs targetting this VCPU.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxx>

Cheers,

> ---
> Changelog v1 ... v2:
> - use irq_set_affinity() directly, avoid vgic_sync_hardware_irq() and lock
>
>   xen/arch/arm/vgic/vgic.c | 39 +++++++++++++++++++++++++++++++++++++++
>   1 file changed, 39 insertions(+)
>
> diff --git a/xen/arch/arm/vgic/vgic.c b/xen/arch/arm/vgic/vgic.c
> index 73cd43f0fa..1aae68ff83 100644
> --- a/xen/arch/arm/vgic/vgic.c
> +++ b/xen/arch/arm/vgic/vgic.c
> @@ -781,6 +781,45 @@ void gic_dump_vgic_info(struct vcpu *v)
>       spin_unlock_irqrestore(&v->arch.vgic.ap_list_lock, flags);
>   }
>   
> +/**
> + * arch_move_irqs() - migrate the physical affinity of hardware mapped vIRQs
> + * @v:  the vCPU, already assigned to the new pCPU
> + *
> + * arch_move_irqs() updates the physical affinity of all virtual IRQs
> + * targetting this given vCPU. This only affects hardware mapped IRQs. The
> + * new pCPU to target is already set in v->processor.
> + * This is called by the core code after a vCPU has been migrated to a new
> + * physical CPU.
> + */
> +void arch_move_irqs(struct vcpu *v)
> +{
> +    struct domain *d = v->domain;
> +    unsigned int i;
> +
> +    /* We only target SPIs with this function */
> +    for ( i = 0; i < d->arch.vgic.nr_spis; i++ )
> +    {
> +        struct vgic_irq *irq = vgic_get_irq(d, NULL, i + VGIC_NR_PRIVATE_IRQS);
> +        unsigned long flags;
> +
> +        if ( !irq )
> +            continue;
> +
> +        spin_lock_irqsave(&irq->irq_lock, flags);
> +
> +        /* only vIRQs that are not on a vCPU yet , but targetting this vCPU */
> +        if ( irq->hw && !irq->vcpu && irq->target_vcpu == v)
> +        {
> +            irq_desc_t *desc = irq_to_desc(irq->hwintid);
> +
> +            irq_set_affinity(desc, cpumask_of(v->processor));
> +        }
> +
> +        spin_unlock_irqrestore(&irq->irq_lock, flags);
> +        vgic_put_irq(d, irq);
> +    }
> +}
> +
>   struct irq_desc *vgic_get_hw_irq_desc(struct domain *d, struct vcpu *v,
>                                         unsigned int virq)
>   {
--
Julien Grall

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