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.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
drivers/irqchip/irq-gic-v3-its.c | 19 +++++++++++++++++--
include/linux/irqchip/arm-gic-v4.h | 2 ++
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 85f47ef4f1f7..2c4074c97454 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1006,9 +1006,15 @@ 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;
@@ -1018,6 +1024,7 @@ static void lpi_write_config(struct irq_data *d, u8 clr, u8 set)
*cfg &= ~clr;
*cfg |= set | LPI_PROP_GROUP1;
+
/*
* Make the above write visible to the redistributors.
* And yes, we're flushing exactly: One. Single. Byte.
@@ -1238,12 +1245,20 @@ 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 43cde15f221b..447da8ca2156 100644
--- 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;
};
--
2.11.0
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