From bed2bd9e1fbef5819090feeada7b86eed97ca5e2 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 3 Jul 2015 12:26:32 +0100 Subject: [PATCH] AArch{32,64}: dynamically configure the number of GIC interrupts In order to reduce the memory usage of large guests (as well as improve performance), tell KVM about the number of interrupts we require. To avoid synchronization with the various device creation, use a late_init callback to compute the GIC configuration. [Andre: rename to gic__init_gic() to ease future expansion] Signed-off-by: Marc Zyngier Signed-off-by: Andre Przywara Signed-off-by: Will Deacon --- arm/gic.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arm/gic.c b/arm/gic.c index 1ff3663..8560c9b 100644 --- a/arm/gic.c +++ b/arm/gic.c @@ -1,10 +1,12 @@ #include "kvm/fdt.h" +#include "kvm/irq.h" #include "kvm/kvm.h" #include "kvm/virtio.h" #include "arm-common/gic.h" #include +#include #include static int gic_fd = -1; @@ -96,6 +98,29 @@ int gic__create(struct kvm *kvm) return err; } +static int gic__init_gic(struct kvm *kvm) +{ + int lines = irq__get_nr_allocated_lines(); + u32 nr_irqs = ALIGN(lines, 32) + GIC_SPI_IRQ_BASE; + struct kvm_device_attr nr_irqs_attr = { + .group = KVM_DEV_ARM_VGIC_GRP_NR_IRQS, + .addr = (u64)(unsigned long)&nr_irqs, + }; + + /* + * If we didn't use the KVM_CREATE_DEVICE method, KVM will + * give us some default number of interrupts. + */ + if (gic_fd < 0) + return 0; + + if (!ioctl(gic_fd, KVM_HAS_DEVICE_ATTR, &nr_irqs_attr)) + return ioctl(gic_fd, KVM_SET_DEVICE_ATTR, &nr_irqs_attr); + + return 0; +} +late_init(gic__init_gic) + void gic__generate_fdt_nodes(void *fdt, u32 phandle) { u64 reg_prop[] = {