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    Subject[PATCH v2 18/52] irqchip/gic-v3-its: Add VLPI configuration handling
    Date
    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 | 73 +++++++++++++++++++++++++++++++++++++---
    1 file changed, 69 insertions(+), 4 deletions(-)

    diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
    index 527e4e95e10d..2e5e0499a0e6 100644
    --- a/drivers/irqchip/irq-gic-v3-its.c
    +++ b/drivers/irqchip/irq-gic-v3-its.c
    @@ -808,18 +808,26 @@ 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)) {
    + 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.
    @@ -830,16 +838,52 @@ 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);
    }

    @@ -852,6 +896,10 @@ 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) {
    @@ -1017,6 +1065,22 @@ 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);
    @@ -1039,6 +1103,7 @@ 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
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