[PATCH v2 5/9] KVM: s390: pv: Add query dump information

[Janosch Frank <frankja@xxxxxxxxxxxxx>]

The dump API requires userspace to provide buffers into which we will
store data. The dump information added in this patch tells userspace
how big those buffers need to be.

Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
 arch/s390/kvm/kvm-s390.c | 11 +++++++++++
 include/uapi/linux/kvm.h | 12 +++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 67e1e445681f..c388d08b9626 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2255,6 +2255,17 @@ static ssize_t kvm_s390_handle_pv_info(struct kvm_s390_pv_info *info)
 
 		return len;
 	}
+	case KVM_PV_INFO_DUMP: {
+		len =  sizeof(info->header) + sizeof(info->dump);
+
+		if (info->header.len_max < len)
+			return -EINVAL;
+
+		info->dump.dump_cpu_buffer_len = uv_info.guest_cpu_stor_len;
+		info->dump.dump_config_mem_buffer_per_1m = uv_info.conf_dump_storage_state_len;
+		info->dump.dump_config_finalize_len = uv_info.conf_dump_finalize_len;
+		return len;
+	}
 	default:
 		return -EINVAL;
 	}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 21f19863c417..eed2ae8397ae 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1645,6 +1645,13 @@ struct kvm_s390_pv_unp {
 
 enum pv_cmd_info_id {
 	KVM_PV_INFO_VM,
+	KVM_PV_INFO_DUMP,
+};
+
+struct kvm_s390_pv_info_dump {
+	__u64 dump_cpu_buffer_len;
+	__u64 dump_config_mem_buffer_per_1m;
+	__u64 dump_config_finalize_len;
 };
 
 struct kvm_s390_pv_info_vm {
@@ -1664,7 +1671,10 @@ struct kvm_s390_pv_info_header {
 
 struct kvm_s390_pv_info {
 	struct kvm_s390_pv_info_header header;
-	struct kvm_s390_pv_info_vm vm;
+	union {
+		struct kvm_s390_pv_info_dump dump;
+		struct kvm_s390_pv_info_vm vm;
+	};
 };
 
 enum pv_cmd_id {
-- 
2.32.0