[PATCH v3 18/59] irqchip/gic-v3-its: Add VLPI configuration handling

Marc Zyngier
2017-07-31T17:26:11Z

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>
---
drivers/irqchip/irq-gic-v3-its.c | 75 +++++++++++++++++++++++++++++++++++++---
1 file changed, 70 insertions(+), 5 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ef31c3e58c01..b618c259be8b 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -806,18 +806,26 @@ 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.
@@ -828,16 +836,52 @@ 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);
}

@@ -850,6 +894,10 @@ 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) {
@@ -1018,6 +1066,22 @@ static int its_vlpi_unmap(struct irq_data *d)
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);
@@ -1040,6 +1104,7 @@ 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;
--
2.11.0