You can use AWS CloudHSM as your root of trust with various software solutions.
KMIP Server Gateway from P6R
Learn the basics of AWS CloudHSM
Presented at AWS re:Inforce 2019
Learn how to use AWS KMS or AWS CloudHSM as root of trust
Announcing the new CloudHSM at NY Summit 2017
For most customers, AWS Key Management Service, backed by FIPS-validated HSMs, offers easier use and better integration than CloudHSM
Secure data in 40+ AWS services with keys in your AWS CloudHSM cluster
Whitepapers and slides
Security and use of AWS CloudHSM.