[PATCH v2 03/11] irqchip/gic-v3-its: Allow LPI invalidation via the DirectLPI interface

[Marc Zyngier]

We currently don't make much use of the DirectLPI feature, and it would
be beneficial to do this more, if only because it becomes a mandatory
feature for GICv4.1.

Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20191027144234.8395-4-maz@xxxxxxxxxx
---
 drivers/irqchip/irq-gic-v3-its.c | 40 +++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 34eab323ea69..576578681117 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -191,6 +191,12 @@ static u16 get_its_list(struct its_vm *vm)
 	return (u16)its_list;
 }
 
+static inline u32 its_get_event_id(struct irq_data *d)
+{
+	struct its_device *its_dev = irq_data_get_irq_chip_data(d);
+	return d->hwirq - its_dev->event_map.lpi_base;
+}
+
 static struct its_collection *dev_event_to_col(struct its_device *its_dev,
 					       u32 event)
 {
@@ -199,6 +205,13 @@ static struct its_collection *dev_event_to_col(struct its_device *its_dev,
 	return its->collections + its_dev->event_map.col_map[event];
 }
 
+static struct its_collection *irq_to_col(struct irq_data *d)
+{
+	struct its_device *its_dev = irq_data_get_irq_chip_data(d);
+
+	return dev_event_to_col(its_dev, its_get_event_id(d));
+}
+
 static struct its_collection *valid_col(struct its_collection *col)
 {
 	if (WARN_ON_ONCE(col->target_address & GENMASK_ULL(15, 0)))
@@ -1046,12 +1059,6 @@ static void its_send_vinvall(struct its_node *its, struct its_vpe *vpe)
  * irqchip functions - assumes MSI, mostly.
  */
 
-static inline u32 its_get_event_id(struct irq_data *d)
-{
-	struct its_device *its_dev = irq_data_get_irq_chip_data(d);
-	return d->hwirq - its_dev->event_map.lpi_base;
-}
-
 static void lpi_write_config(struct irq_data *d, u8 clr, u8 set)
 {
 	irq_hw_number_t hwirq;
@@ -1096,12 +1103,28 @@ static void wait_for_syncr(void __iomem *rdbase)
 		cpu_relax();
 }
 
+static void direct_lpi_inv(struct irq_data *d)
+{
+	struct its_collection *col;
+	void __iomem *rdbase;
+
+	/* Target the redistributor this LPI is currently routed to */
+	col = irq_to_col(d);
+	rdbase = per_cpu_ptr(gic_rdists->rdist, col->col_id)->rd_base;
+	gic_write_lpir(d->hwirq, rdbase + GICR_INVLPIR);
+
+	wait_for_syncr(rdbase);
+}
+
 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);
 
 	lpi_write_config(d, clr, set);
-	its_send_inv(its_dev, its_get_event_id(d));
+	if (gic_rdists->has_direct_lpi && !irqd_is_forwarded_to_vcpu(d))
+		direct_lpi_inv(d);
+	else
+		its_send_inv(its_dev, its_get_event_id(d));
 }
 
 static void its_vlpi_set_doorbell(struct irq_data *d, bool enable)
@@ -2932,8 +2955,9 @@ static void its_vpe_send_inv(struct irq_data *d)
 	if (gic_rdists->has_direct_lpi) {
 		void __iomem *rdbase;
 
+		/* Target the redistributor this VPE is currently known on */
 		rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
-		gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_INVLPIR);
+		gic_write_lpir(d->parent_data->hwirq, rdbase + GICR_INVLPIR);
 		wait_for_syncr(rdbase);
 	} else {
 		its_vpe_send_cmd(vpe, its_send_inv);
-- 
2.20.1