KVM: arm/arm64: vgic: add init entry to VGIC KVM device

Since the advent of VGIC dynamic initialization, this latter is
initialized quite late on the first vcpu run or "on-demand", when
injecting an IRQ or when the guest sets its registers.

This initialization could be initiated explicitly much earlier
by the users-space, as soon as it has provided the requested
dimensioning parameters.

This patch adds a new entry to the VGIC KVM device that allows
the user to manually request the VGIC init:
- a new KVM_DEV_ARM_VGIC_GRP_CTRL group is introduced.
- Its first attribute is KVM_DEV_ARM_VGIC_CTRL_INIT

The rationale behind introducing a group is to be able to add other
controls later on, if needed.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index b8d57e86cfdc..c84f53dfcd62 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -2302,7 +2302,14 @@ static int vgic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 
 		return ret;
 	}
-
+	case KVM_DEV_ARM_VGIC_GRP_CTRL: {
+		switch (attr->attr) {
+		case KVM_DEV_ARM_VGIC_CTRL_INIT:
+			r = vgic_init(dev->kvm);
+			return r;
+		}
+		break;
+	}
 	}
 
 	return -ENXIO;
@@ -2381,6 +2388,11 @@ static int vgic_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 		return vgic_has_attr_regs(vgic_cpu_ranges, offset);
 	case KVM_DEV_ARM_VGIC_GRP_NR_IRQS:
 		return 0;
+	case KVM_DEV_ARM_VGIC_GRP_CTRL:
+		switch (attr->attr) {
+		case KVM_DEV_ARM_VGIC_CTRL_INIT:
+			return 0;
+		}
 	}
 	return -ENXIO;
 }