irqchip/gic-v3-its: Add VLPI configuration handling

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.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 5187c4b116d48d158e2770c5b182139dfc4b27c7..0aa4d609a8e91565136900859029728536fa07e7 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -812,18 +812,26 @@ static inline u32 its_get_event_id(struct irq_data *d)
        return d->hwirq - its_dev->event_map.lpi_base;
 }
 
-static void lpi_update_config(struct irq_data *d, u8 clr, u8 set)
+static void lpi_write_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)) {
+               struct its_device *its_dev = irq_data_get_irq_chip_data(d);
+               u32 event = its_get_event_id(d);
+
+               prop_page = its_dev->event_map.vm->vprop_page;
+               hwirq = its_dev->event_map.vlpi_maps[event].vintid;
+       } else {
+               prop_page = gic_rdists->prop_page;
+               hwirq = d->hwirq;
+       }
 
        cfg = page_address(prop_page) + hwirq - 8192;
        *cfg &= ~clr;
-       *cfg |= set;
+       *cfg |= set | LPI_PROP_GROUP1;
 
        /*
         * Make the above write visible to the redistributors.
@@ -834,16 +842,52 @@ static void lpi_update_config(struct irq_data *d, u8 clr, u8 set)
                gic_flush_dcache_to_poc(cfg, sizeof(*cfg));
        else
                dsb(ishst);
+}
+
+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));
 }
 
+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);
+
+       if (its_dev->event_map.vlpi_maps[event].db_enabled == enable)
+               return;
+
+       its_dev->event_map.vlpi_maps[event].db_enabled = enable;
+
+       /*
+        * More fun with the architecture:
+        *
+        * Ideally, we'd issue a VMAPTI to set the doorbell to its LPI
+        * value or to 1023, depending on the enable bit. But that
+        * would be issueing a mapping for an /existing/ DevID+EventID
+        * pair, which is UNPREDICTABLE. Instead, let's issue a VMOVI
+        * to the /same/ vPE, using this opportunity to adjust the
+        * doorbell. Mouahahahaha. We loves it, Precious.
+        */
+       its_send_vmovi(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);
 }
 
@@ -856,6 +900,10 @@ 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) {
@@ -1024,6 +1072,22 @@ out:
        return ret;
 }
 
+static int its_vlpi_prop_update(struct irq_data *d, struct its_cmd_info *info)
+{
+       struct its_device *its_dev = irq_data_get_irq_chip_data(d);
+
+       if (!its_dev->event_map.vm || !irqd_is_forwarded_to_vcpu(d))
+               return -EINVAL;
+
+       if (info->cmd_type == PROP_UPDATE_AND_INV_VLPI)
+               lpi_update_config(d, 0xff, info->config);
+       else
+               lpi_write_config(d, 0xff, info->config);
+       its_vlpi_set_doorbell(d, !!(info->config & LPI_PROP_ENABLED));
+
+       return 0;
+}
+
 static int its_irq_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
 {
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
@@ -1046,6 +1110,7 @@ static int its_irq_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
 
        case PROP_UPDATE_VLPI:
        case PROP_UPDATE_AND_INV_VLPI:
+               return its_vlpi_prop_update(d, info);
 
        default:
                return -EINVAL;