At the moment kvmtool always tries to instantiate a virtual GICv2 interrupt controller for the guest, and fails with some scary error message if that doesn't work. The user has then to manually specify "--irqchip=gicv3", which is not really obvious. With the advent of more GICv3-only machines, let's try to be more clever and implement some auto-detection of the GIC type needed: We try gicv3-its, gicv3, gicv2m and gicv2, in that order. The first one succeeding wins. For GICv2 machines the first two will always fail. On GICv3 machines offering GICv2 compatibility we used to prefer a virtual GICv2 in the guest, but these days the GICv3 support both in guests and in KVM is equally mature and wide-spread, so we should use the GICv3 emulation for the guest as well.
This algorithm is in effect is there is no explicit --irqchip parameter on the command line. We still allow the GIC type to be set explicitly. Signed-off-by: Andre Przywara <[email protected]> --- arm/gic.c | 16 ++++++++++++++++ arm/include/arm-common/gic.h | 1 + 2 files changed, 17 insertions(+) diff --git a/arm/gic.c b/arm/gic.c index abcbcc09..26be4b4c 100644 --- a/arm/gic.c +++ b/arm/gic.c @@ -182,6 +182,8 @@ static int gic__create_device(struct kvm *kvm, enum irqchip_type type) gic_device.type = KVM_DEV_TYPE_ARM_VGIC_V3; dist_attr.attr = KVM_VGIC_V3_ADDR_TYPE_DIST; break; + case IRQCHIP_AUTO: + return -ENODEV; } err = ioctl(kvm->vm_fd, KVM_CREATE_DEVICE, &gic_device); @@ -199,6 +201,8 @@ static int gic__create_device(struct kvm *kvm, enum irqchip_type type) case IRQCHIP_GICV3: err = ioctl(gic_fd, KVM_SET_DEVICE_ATTR, &redist_attr); break; + case IRQCHIP_AUTO: + return -ENODEV; } if (err) goto out_err; @@ -249,9 +253,21 @@ static int gic__create_irqchip(struct kvm *kvm) int gic__create(struct kvm *kvm, enum irqchip_type type) { + enum irqchip_type try; int err; switch (type) { + case IRQCHIP_AUTO: + for (try = IRQCHIP_GICV3_ITS; try >= IRQCHIP_GICV2; try--) { + err = gic__create(kvm, try); + if (!err) + break; + } + if (err) + return err; + + kvm->cfg.arch.irqchip = try; + return 0; case IRQCHIP_GICV2M: gic_msi_size = KVM_VGIC_V2M_SIZE; gic_msi_base = ARM_GIC_CPUI_BASE - gic_msi_size; diff --git a/arm/include/arm-common/gic.h b/arm/include/arm-common/gic.h index 1125d601..ec9cf31a 100644 --- a/arm/include/arm-common/gic.h +++ b/arm/include/arm-common/gic.h @@ -24,6 +24,7 @@ #define KVM_VGIC_V2M_SIZE 0x1000 enum irqchip_type { + IRQCHIP_AUTO, IRQCHIP_GICV2, IRQCHIP_GICV2M, IRQCHIP_GICV3, -- 2.17.1 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
