KVM: arm/arm64: vgic: Implement KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO ioctl

Userspace requires to store and restore of line_level for
level triggered interrupts using ioctl KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO.
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Signed-off-by: NVijaya Kumar K <Vijaya.Kumar@cavium.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

arch/arm/include/uapi/asm/kvm.h

@@ -191,6 +191,12 @@ struct kvm_arch_memory_slot {
 #define KVM_DEV_ARM_VGIC_GRP_CTRL       4
 #define KVM_DEV_ARM_VGIC_GRP_REDIST_REGS 5
 #define KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS 6
+#define KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO  7
+#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT	10
+#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_MASK \
+			(0x3fffffULL << KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT)
+#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INTID_MASK 0x3ff
+#define VGIC_LEVEL_INFO_LINE_LEVEL	0
 
 #define   KVM_DEV_ARM_VGIC_CTRL_INIT    0
 

arch/arm64/include/uapi/asm/kvm.h

@@ -211,6 +211,12 @@ struct kvm_arch_memory_slot {
 #define KVM_DEV_ARM_VGIC_GRP_CTRL	4
 #define KVM_DEV_ARM_VGIC_GRP_REDIST_REGS 5
 #define KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS 6
+#define KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO  7
+#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT	10
+#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_MASK \
+			(0x3fffffULL << KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT)
+#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INTID_MASK	0x3ff
+#define VGIC_LEVEL_INFO_LINE_LEVEL	0
 
 #define   KVM_DEV_ARM_VGIC_CTRL_INIT	0
 

virt/kvm/arm/vgic/vgic-kvm-device.c

@@ -512,6 +512,21 @@ static int vgic_v3_attr_regs_access(struct kvm_device *dev,
 						  regid, reg);
 		break;
 	}
+	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
+		unsigned int info, intid;
+
+		info = (attr->attr & KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_MASK) >>
+			KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT;
+		if (info == VGIC_LEVEL_INFO_LINE_LEVEL) {
+			intid = attr->attr &
+				KVM_DEV_ARM_VGIC_LINE_LEVEL_INTID_MASK;
+			ret = vgic_v3_line_level_info_uaccess(vcpu, is_write,
+							      intid, reg);
+		} else {
+			ret = -EINVAL;
+		}
+		break;
+	}
 	default:
 		ret = -EINVAL;
 		break;
@@ -554,6 +569,17 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
 
 		return vgic_v3_attr_regs_access(dev, attr, &reg, true);
 	}
+	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
+		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
+		u64 reg;
+		u32 tmp32;
+
+		if (get_user(tmp32, uaddr))
+			return -EFAULT;
+
+		reg = tmp32;
+		return vgic_v3_attr_regs_access(dev, attr, &reg, true);
+	}
 	}
 	return -ENXIO;
 }
@@ -589,8 +615,18 @@ static int vgic_v3_get_attr(struct kvm_device *dev,
 			return ret;
 		return put_user(reg, uaddr);
 	}
-	}
+	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
+		u32 __user *uaddr = (u32 __user *)(long)attr->addr;
+		u64 reg;
+		u32 tmp32;
 
+		ret = vgic_v3_attr_regs_access(dev, attr, &reg, false);
+		if (ret)
+			return ret;
+		tmp32 = reg;
+		return put_user(tmp32, uaddr);
+	}
+	}
 	return -ENXIO;
 }
 
@@ -611,6 +647,13 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
 		return vgic_v3_has_attr_regs(dev, attr);
 	case KVM_DEV_ARM_VGIC_GRP_NR_IRQS:
 		return 0;
+	case KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO: {
+		if (((attr->attr & KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_MASK) >>
+		      KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT) ==
+		      VGIC_LEVEL_INFO_LINE_LEVEL)
+			return 0;
+		break;
+	}
 	case KVM_DEV_ARM_VGIC_GRP_CTRL:
 		switch (attr->attr) {
 		case KVM_DEV_ARM_VGIC_CTRL_INIT:

virt/kvm/arm/vgic/vgic-mmio-v3.c

@@ -803,3 +803,17 @@ int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 	else
 		return vgic_uaccess(vcpu, &rd_dev, is_write, offset, val);
 }
+
+int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
+				    u32 intid, u64 *val)
+{
+	if (intid % 32)
+		return -EINVAL;
+
+	if (is_write)
+		vgic_write_irq_line_level_info(vcpu, intid, *val);
+	else
+		*val = vgic_read_irq_line_level_info(vcpu, intid);
+
+	return 0;
+}

virt/kvm/arm/vgic/vgic-mmio.c

@@ -362,6 +362,60 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
 	}
 }
 
+u64 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid)
+{
+	int i;
+	u64 val = 0;
+	int nr_irqs = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
+
+	for (i = 0; i < 32; i++) {
+		struct vgic_irq *irq;
+
+		if ((intid + i) < VGIC_NR_SGIS || (intid + i) >= nr_irqs)
+			continue;
+
+		irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+		if (irq->config == VGIC_CONFIG_LEVEL && irq->line_level)
+			val |= (1U << i);
+
+		vgic_put_irq(vcpu->kvm, irq);
+	}
+
+	return val;
+}
+
+void vgic_write_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid,
+				    const u64 val)
+{
+	int i;
+	int nr_irqs = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
+
+	for (i = 0; i < 32; i++) {
+		struct vgic_irq *irq;
+		bool new_level;
+
+		if ((intid + i) < VGIC_NR_SGIS || (intid + i) >= nr_irqs)
+			continue;
+
+		irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+		/*
+		 * Line level is set irrespective of irq type
+		 * (level or edge) to avoid dependency that VM should
+		 * restore irq config before line level.
+		 */
+		new_level = !!(val & (1U << i));
+		spin_lock(&irq->irq_lock);
+		irq->line_level = new_level;
+		if (new_level)
+			vgic_queue_irq_unlock(vcpu->kvm, irq);
+		else
+			spin_unlock(&irq->irq_lock);
+
+		vgic_put_irq(vcpu->kvm, irq);
+	}
+}
+
 static int match_region(const void *key, const void *elt)
 {
 	const unsigned int offset = (unsigned long)key;

virt/kvm/arm/vgic/vgic-mmio.h

@@ -177,6 +177,11 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
 int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
 		 bool is_write, int offset, u32 *val);
 
+u64 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid);
+
+void vgic_write_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid,
+				    const u64 val);
+
 unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
 
 unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev);

virt/kvm/arm/vgic/vgic.h

@@ -164,6 +164,8 @@ int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 			 u64 id, u64 *val);
 int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
 				u64 *reg);
+int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
+				    u32 intid, u64 *val);
 int kvm_register_vgic_device(unsigned long type);
 void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
 void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);