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

[Marc Zyngier]

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 at arm.com>
---
 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;
 	}
 
-- 
2.1.4