irqchip/gic-v3-its: Setup VLPI properties at map time

So far, we require the hypervisor to update the VLPI properties
once the the VLPI mapping has been established. While this
makes it easy for the ITS driver, it creates a window where
an incoming interrupt can be delivered with an unknown set
of properties. Not very nice.

Instead, let's add a "properties" field to the mapping structure,
and use that to configure the VLPI before it actually gets mapped.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
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 6a74f0497f822525b0a305ab66183e4203c995de..29b2ff5c684180b17885fbd8057e8629e196148b 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1008,9 +1008,15 @@ static void lpi_write_config(struct irq_data *d, u8 clr, u8 set)
        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);
+               struct its_vlpi_map *map;
 
                prop_page = its_dev->event_map.vm->vprop_page;
-               hwirq = its_dev->event_map.vlpi_maps[event].vintid;
+               map = &its_dev->event_map.vlpi_maps[event];
+               hwirq = map->vintid;
+
+               /* Remember the updated property */
+               map->properties &= ~clr;
+               map->properties |= set | LPI_PROP_GROUP1;
        } else {
                prop_page = gic_rdists->prop_page;
                hwirq = d->hwirq;
@@ -1249,12 +1255,20 @@ static int its_vlpi_map(struct irq_data *d, struct its_cmd_info *info)
                /* Ensure all the VPEs are mapped on this ITS */
                its_map_vm(its_dev->its, info->map->vm);
 
+               /*
+                * Flag the interrupt as forwarded so that we can
+                * start poking the virtual property table.
+                */
+               irqd_set_forwarded_to_vcpu(d);
+
+               /* Write out the property to the prop table */
+               lpi_write_config(d, 0xff, info->map->properties);
+
                /* Drop the physical mapping */
                its_send_discard(its_dev, event);
 
                /* and install the virtual one */
                its_send_vmapti(its_dev, event);
-               irqd_set_forwarded_to_vcpu(d);
 
                /* Increment the number of VLPIs */
                its_dev->event_map.nr_vlpis++;

diff --git a/include/linux/irqchip/arm-gic-v4.h b/include/linux/irqchip/arm-gic-v4.h
index 43cde15f221bb92c2a4e751a4c9237d69191b48d..447da8ca2156221749876d53c84430c62e729980 100644 (file)
--- a/include/linux/irqchip/arm-gic-v4.h
+++ b/include/linux/irqchip/arm-gic-v4.h
@@ -71,12 +71,14 @@ struct its_vpe {
  * @vm:                Pointer to the GICv4 notion of a VM
  * @vpe:       Pointer to the GICv4 notion of a virtual CPU (VPE)
  * @vintid:    Virtual LPI number
+ * @properties:        Priority and enable bits (as written in the prop table)
  * @db_enabled:        Is the VPE doorbell to be generated?
  */
 struct its_vlpi_map {
        struct its_vm           *vm;
        struct its_vpe          *vpe;
        u32                     vintid;
+       u8                      properties;
        bool                    db_enabled;
 };