[PATCH 3/9] KVM: s390: pv: Add query interface

[Janosch Frank <frankja@xxxxxxxxxxxxx>]

Some of the query information is already available via sysfs but
having a IOCTL makes the information easier to retrieve.

Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
 arch/s390/kvm/kvm-s390.c | 47 ++++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/kvm.h | 23 ++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index faa85397b6fb..837f898ad2ff 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2217,6 +2217,34 @@ static int kvm_s390_cpus_to_pv(struct kvm *kvm, u16 *rc, u16 *rrc)
 	return r;
 }
 
+static int kvm_s390_handle_pv_info(struct kvm_s390_pv_info *info)
+{
+	u32 len;
+
+	switch (info->header.id) {
+	case KVM_PV_INFO_VM: {
+		len =  sizeof(info->header) + sizeof(info->vm);
+
+		if (info->header.len < len)
+			return -EINVAL;
+
+		memcpy(info->vm.inst_calls_list,
+		       uv_info.inst_calls_list,
+		       sizeof(uv_info.inst_calls_list));
+
+		/* It's max cpuidm not max cpus so it's off by one */
+		info->vm.max_cpus = uv_info.max_guest_cpu_id + 1;
+		info->vm.max_guests = uv_info.max_num_sec_conf;
+		info->vm.max_guest_addr = uv_info.max_sec_stor_addr;
+		info->vm.feature_indication = uv_info.uv_feature_indications;
+
+		return 0;
+	}
+	default:
+		return -EINVAL;
+	}
+}
+
 static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
 {
 	int r = 0;
@@ -2353,6 +2381,25 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
 			     cmd->rc, cmd->rrc);
 		break;
 	}
+	case KVM_PV_INFO: {
+		struct kvm_s390_pv_info info = {};
+
+		if (copy_from_user(&info, argp, sizeof(info.header)))
+			return -EFAULT;
+
+		if (info.header.len < sizeof(info.header))
+			return -EINVAL;
+
+		r = kvm_s390_handle_pv_info(&info);
+		if (r)
+			return r;
+
+		r = copy_to_user(argp, &info, sizeof(info));
+
+		if (r)
+			return -EFAULT;
+		return 0;
+	}
 	default:
 		r = -ENOTTY;
 	}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index dbc550bbd9fa..96fceb204a92 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1642,6 +1642,28 @@ struct kvm_s390_pv_unp {
 	__u64 tweak;
 };
 
+enum pv_cmd_info_id {
+	KVM_PV_INFO_VM,
+};
+
+struct kvm_s390_pv_info_vm {
+	__u64 inst_calls_list[4];
+	__u64 max_cpus;
+	__u64 max_guests;
+	__u64 max_guest_addr;
+	__u64 feature_indication;
+};
+
+struct kvm_s390_pv_info_header {
+	__u32 id;
+	__u32 len;
+};
+
+struct kvm_s390_pv_info {
+	struct kvm_s390_pv_info_header header;
+	struct kvm_s390_pv_info_vm vm;
+};
+
 enum pv_cmd_id {
 	KVM_PV_ENABLE,
 	KVM_PV_DISABLE,
@@ -1650,6 +1672,7 @@ enum pv_cmd_id {
 	KVM_PV_VERIFY,
 	KVM_PV_PREP_RESET,
 	KVM_PV_UNSHARE_ALL,
+	KVM_PV_INFO,
 };
 
 struct kvm_pv_cmd {
-- 
2.32.0