diff options
Diffstat (limited to 'drivers/iommu/intel/irq_remapping.c')
| -rw-r--r-- | drivers/iommu/intel/irq_remapping.c | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c index ea3ca5203919..3bc2a03cceca 100644 --- a/drivers/iommu/intel/irq_remapping.c +++ b/drivers/iommu/intel/irq_remapping.c @@ -1287,43 +1287,44 @@ static struct irq_chip intel_ir_chip = { }; /* - * With posted MSIs, all vectors are multiplexed into a single notification - * vector. Devices MSIs are then dispatched in a demux loop where - * EOIs can be coalesced as well. + * With posted MSIs, the MSI vectors are multiplexed into a single notification + * vector, and only the notification vector is sent to the APIC IRR. Device + * MSIs are then dispatched in a demux loop that harvests the MSIs from the + * CPU's Posted Interrupt Request bitmap. I.e. Posted MSIs never get sent to + * the APIC IRR, and thus do not need an EOI. The notification handler instead + * performs a single EOI after processing the PIR. * - * "INTEL-IR-POST" IRQ chip does not do EOI on ACK, thus the dummy irq_ack() - * function. Instead EOI is performed by the posted interrupt notification - * handler. + * Note! Pending SMP/CPU affinity changes, which are per MSI, must still be + * honored, only the APIC EOI is omitted. * * For the example below, 3 MSIs are coalesced into one CPU notification. Only - * one apic_eoi() is needed. + * one apic_eoi() is needed, but each MSI needs to process pending changes to + * its CPU affinity. * * __sysvec_posted_msi_notification() * irq_enter(); * handle_edge_irq() * irq_chip_ack_parent() - * dummy(); // No EOI + * irq_move_irq(); // No EOI * handle_irq_event() * driver_handler() * handle_edge_irq() * irq_chip_ack_parent() - * dummy(); // No EOI + * irq_move_irq(); // No EOI * handle_irq_event() * driver_handler() * handle_edge_irq() * irq_chip_ack_parent() - * dummy(); // No EOI + * irq_move_irq(); // No EOI * handle_irq_event() * driver_handler() * apic_eoi() * irq_exit() + * */ - -static void dummy_ack(struct irq_data *d) { } - static struct irq_chip intel_ir_chip_post_msi = { .name = "INTEL-IR-POST", - .irq_ack = dummy_ack, + .irq_ack = irq_move_irq, .irq_set_affinity = intel_ir_set_affinity, .irq_compose_msi_msg = intel_ir_compose_msi_msg, .irq_set_vcpu_affinity = intel_ir_set_vcpu_affinity, |