!2918 fix some bugs in loongarch kvm

Merge Pull Request from: @lixianglai 
 
https://gitee.com/openeuler/kernel/issues/I8I8NK
https://gitee.com/openeuler/kernel/issues/I8I3QU
https://gitee.com/openeuler/kernel/issues/I8I4BU
 
 
Link:https://gitee.com/openeuler/kernel/pulls/2918

 

Reviewed-by: Kevin Zhu <zhukeqian1@huawei.com>
Reviewed-by: Mao Bibo <maobibo@loongson.cn>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>