KVM: x86/xen: Add KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTR

This will be used for per-vCPU setup such as runstate and vcpu_info.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

arch/x86/kvm/x86.c

@@ -5016,6 +5016,26 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	case KVM_GET_SUPPORTED_HV_CPUID:
 		r = kvm_ioctl_get_supported_hv_cpuid(vcpu, argp);
 		break;
+	case KVM_XEN_VCPU_GET_ATTR: {
+		struct kvm_xen_vcpu_attr xva;
+
+		r = -EFAULT;
+		if (copy_from_user(&xva, argp, sizeof(xva)))
+			goto out;
+		r = kvm_xen_vcpu_get_attr(vcpu, &xva);
+		if (!r && copy_to_user(argp, &xva, sizeof(xva)))
+			r = -EFAULT;
+		break;
+	}
+	case KVM_XEN_VCPU_SET_ATTR: {
+		struct kvm_xen_vcpu_attr xva;
+
+		r = -EFAULT;
+		if (copy_from_user(&xva, argp, sizeof(xva)))
+			goto out;
+		r = kvm_xen_vcpu_set_attr(vcpu, &xva);
+		break;
+	}
 	default:
 		r = -EINVAL;
 	}

arch/x86/kvm/xen.c

@@ -118,6 +118,36 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 	return r;
 }
 
+int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
+{
+	int r = -ENOENT;
+
+	mutex_lock(&vcpu->kvm->lock);
+
+	switch (data->type) {
+	default:
+		break;
+	}
+
+	mutex_unlock(&vcpu->kvm->lock);
+	return r;
+}
+
+int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
+{
+	int r = -ENOENT;
+
+	mutex_lock(&vcpu->kvm->lock);
+
+	switch (data->type) {
+	default:
+		break;
+	}
+
+	mutex_unlock(&vcpu->kvm->lock);
+	return r;
+}
+
 int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
 {
 	struct kvm *kvm = vcpu->kvm;

arch/x86/kvm/xen.h

@@ -13,6 +13,8 @@
 
 extern struct static_key_false_deferred kvm_xen_enabled;
 
+int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data);
+int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data);
 int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
 int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
 int kvm_xen_hypercall(struct kvm_vcpu *vcpu);

include/uapi/linux/kvm.h

@@ -1587,6 +1587,7 @@ struct kvm_pv_cmd {
 /* Available with KVM_CAP_DIRTY_LOG_RING */
 #define KVM_RESET_DIRTY_RINGS		_IO(KVMIO, 0xc7)
 
+/* Per-VM Xen attributes */
 #define KVM_XEN_HVM_GET_ATTR	_IOWR(KVMIO, 0xc8, struct kvm_xen_hvm_attr)
 #define KVM_XEN_HVM_SET_ATTR	_IOW(KVMIO,  0xc9, struct kvm_xen_hvm_attr)
 
@@ -1605,6 +1606,18 @@ struct kvm_xen_hvm_attr {
 #define KVM_XEN_ATTR_TYPE_LONG_MODE		0x0
 #define KVM_XEN_ATTR_TYPE_SHARED_INFO		0x1
 
+/* Per-vCPU Xen attributes */
+#define KVM_XEN_VCPU_GET_ATTR	_IOWR(KVMIO, 0xca, struct kvm_xen_vcpu_attr)
+#define KVM_XEN_VCPU_SET_ATTR	_IOW(KVMIO,  0xcb, struct kvm_xen_vcpu_attr)
+
+struct kvm_xen_vcpu_attr {
+	__u16 type;
+	__u16 pad[3];
+	union {
+		__u64 pad[8];
+	} u;
+};
+
 /* Secure Encrypted Virtualization command */
 enum sev_cmd_id {
 	/* Guest initialization commands */