[PATCH] KVM: Add KVM_CAP_IRQ_ARCH capability

[Paul Mackerras <paulus@samba.org>]

Setting this capability on a vcpu connects that vcpu to an interrupt
controller device.  The args[0] field of the argument kvm_enable_cap
struct specifies the overall architecture of the interrupt
controller.  The args[1] field specifies the CPU number for the vcpu
from the interrupt controller's point of view.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
 arch/powerpc/include/asm/kvm_host.h |    3 +++
 arch/powerpc/kvm/powerpc.c          |   29 +++++++++++++++++++++++++++++
 include/uapi/linux/kvm.h            |    1 +
 3 files changed, 33 insertions(+)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index f4ba881..dd167e4 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -373,6 +373,9 @@ struct kvmppc_booke_debug_reg {
 struct kvm_vcpu_arch {
 	ulong host_stack;
 	u32 host_pid;
+
+	u32 intr_ctrler;
+
 #ifdef CONFIG_PPC_BOOK3S
 	struct kvmppc_slb slb[64];
 	int slb_max;		/* 1 + index of last valid entry in slb[] */
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 934413c..891603e 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -459,6 +459,12 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 	hrtimer_cancel(&vcpu->arch.dec_timer);
 	tasklet_kill(&vcpu->arch.tasklet);
 
+	/* Release any per-vcpu irq controller state */
+	switch (vcpu->arch.intr_ctrler) {
+	default:
+		break;
+	}
+
 	kvmppc_remove_vcpu_debugfs(vcpu);
 	kvmppc_core_vcpu_free(vcpu);
 }
@@ -791,6 +797,29 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
 		break;
 	}
 #endif
+	case KVM_CAP_IRQ_ARCH:
+		r = -EBUSY;
+		mutex_lock(&vcpu->kvm->lock);
+		/* disallow changing once set */
+		if (!vcpu->arch.intr_ctrler) {
+			r = 0;
+			switch (cap->args[0]) {
+			case 0:		/* no interrupt controller */
+				break;
+			default:
+				r = -EINVAL;
+			}
+			if (!r) {
+				/*
+				 * Make sure any state set up by the interrupt
+				 * controller init routine is seen before this.
+				 */
+				smp_wmb();
+				vcpu->arch.intr_ctrler = cap->args[0];
+			}
+		}
+		mutex_unlock(&vcpu->kvm->lock);
+		break;
 	default:
 		r = -EINVAL;
 		break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 1f348e0..d875d37 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -663,6 +663,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_S390_CSS_SUPPORT 85
 #define KVM_CAP_PPC_EPR 86
 #define KVM_CAP_DEVICE_CTRL 87
+#define KVM_CAP_IRQ_ARCH 88
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
1.7.10.4