Re: [RFC PATCH 19/33] irqchip/gic-v3-its: Add VLPI configuration handling

[Auger Eric]

Hi,

On 17/01/2017 11:20, Marc Zyngier wrote:
> When a VLPI is reconfigured (enabled, disabled, change in priority),
> the full configuration byte must be written, and the caches invalidated.
> 
> Also, when using the irq_mask/irq_unmask methods, it is necessary
> to disable the doorbell for that particular interrupt (by mapping it
> to 1023) on top of clearing the Enable bit.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>

> ---
>  drivers/irqchip/irq-gic-v3-its.c | 37 +++++++++++++++++++++++++++++++++++--
>  1 file changed, 35 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index d50a019..6931018 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -796,11 +796,18 @@ static inline u32 its_get_event_id(struct irq_data *d)
>  static void lpi_update_config(struct irq_data *d, u8 clr, u8 set)
>  {
>  	struct its_device *its_dev = irq_data_get_irq_chip_data(d);
> -	irq_hw_number_t hwirq = d->hwirq;
> +	irq_hw_number_t hwirq;
>  	struct page *prop_page;
>  	u8 *cfg;
>  
> -	prop_page = gic_rdists->prop_page;
> +	if (irqd_is_forwarded_to_vcpu(d)) {
> +		u32 event = its_get_event_id(d);
> +		prop_page = its_dev->event_map.vlpi_map->vpes[0]->its_vm->vprop_page;
> +		hwirq = its_dev->event_map.vlpi_map->vlpis[event].vintid;
> +	} else {
> +		prop_page = gic_rdists->prop_page;
> +		hwirq = d->hwirq;
> +	}
>  
>  	cfg = page_address(prop_page) + hwirq - 8192;
>  	*cfg &= ~clr;
> @@ -818,13 +825,28 @@ static void lpi_update_config(struct irq_data *d, u8 clr, u8 set)
>  	its_send_inv(its_dev, its_get_event_id(d));
>  }
>  
> +static void its_vlpi_set_doorbell(struct irq_data *d, bool enable)
> +{
> +	struct its_device *its_dev = irq_data_get_irq_chip_data(d);
> +	u32 event = its_get_event_id(d);
> +
> +	its_dev->event_map.vlpi_map->vlpis[event].db_enabled = enable;
> +	its_send_vmapti(its_dev, event);
> +}
> +
>  static void its_mask_irq(struct irq_data *d)
>  {
> +	if (irqd_is_forwarded_to_vcpu(d))
> +		its_vlpi_set_doorbell(d, false);
> +
>  	lpi_update_config(d, LPI_PROP_ENABLED, 0);
>  }
>  
>  static void its_unmask_irq(struct irq_data *d)
>  {
> +	if (irqd_is_forwarded_to_vcpu(d))
> +		its_vlpi_set_doorbell(d, true);
> +
>  	lpi_update_config(d, 0, LPI_PROP_ENABLED);
>  }
>  
> @@ -837,6 +859,10 @@ static int its_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
>  	struct its_collection *target_col;
>  	u32 id = its_get_event_id(d);
>  
> +	/* A forwarded interrupt should use irq_set_vcpu_affinity */
> +	if (irqd_is_forwarded_to_vcpu(d))
> +		return -EINVAL;
> +
>         /* lpi cannot be routed to a redistributor that is on a foreign node */
>  	if (its_dev->its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144) {
>  		if (its_dev->its->numa_node >= 0) {
> @@ -969,6 +995,13 @@ static int its_irq_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
>  
>  	case PROP_UPDATE_VLPI:
>  	{
> +		if (!its_dev->event_map.vlpi_map ||
> +		    !irqd_is_forwarded_to_vcpu(d))
> +			return -EINVAL;
> +
> +		lpi_update_config(d, 0xff, info->config);
> +		its_vlpi_set_doorbell(d, !!(info->config & LPI_PROP_ENABLED));
> +
>  		return 0;
>  	}
>  
>