[PATCH v2 10/29] LoongArch: KVM: Implement vcpu ENABLE_CAP, CHECK_EXTENSION ioctl interface

[Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>]

Implement loongarch vcpu KVM_ENABLE_CAP, KVM_CHECK_EXTENSION ioctl
interface.

Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
 arch/loongarch/kvm/vcpu.c | 46 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 4b7642bce..2ad9d126e 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -356,6 +356,29 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
 	return 0;
 }
 
+static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
+				     struct kvm_enable_cap *cap)
+{
+	int r = 0;
+
+	if (!kvm_vm_ioctl_check_extension(vcpu->kvm, cap->cap))
+		return -EINVAL;
+	if (cap->flags)
+		return -EINVAL;
+	if (cap->args[0])
+		return -EINVAL;
+
+	switch (cap->cap) {
+	case KVM_CAP_LOONGARCH_FPU:
+		break;
+	default:
+		r = -EINVAL;
+		break;
+	}
+
+	return r;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp,
 			 unsigned int ioctl, unsigned long arg)
 {
@@ -379,6 +402,29 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 			r = _kvm_get_reg(vcpu, &reg);
 		break;
 	}
+	case KVM_ENABLE_CAP: {
+		struct kvm_enable_cap cap;
+
+		r = -EFAULT;
+		if (copy_from_user(&cap, argp, sizeof(cap)))
+			break;
+		r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
+		break;
+	}
+	case KVM_CHECK_EXTENSION: {
+		unsigned int ext;
+
+		if (copy_from_user(&ext, argp, sizeof(ext)))
+			return -EFAULT;
+		switch (ext) {
+		case KVM_CAP_LOONGARCH_FPU:
+			r = !!cpu_has_fpu;
+			break;
+		default:
+			break;
+		}
+		break;
+	}
 	default:
 		r = -ENOIOCTLCMD;
 		break;
-- 
2.31.1