Function tdx_guest::tdvmcall::get_td_service

pub fn get_td_service(
    shared_gpa_input: u64,
    shared_gpa_output: u64,
    interrupt_vector: u64,
    time_out: u64,
) -> Result<(), TdVmcallError>

In Service TD scenario, there is a need to define interfaces for the command/response that may have long latency, such as communicating with local device via Secure Protocol and Data Model (SPDM), communicating with remote platform via Transport Layer Security (TLS) Protocol, or communicating with a Quoting Enclave (QE) on attestation or mutual authentication.

There is also needed that the VMM may notify a service TD to do some actions, such as Migration TD (MigTD).

We define Command/Response Buffer (CRB) DMA interface.

Inputs:

• shared_gpa_input: Shared 4KB aligned GPA as input – the memory contains a Command. It could be more than one 4K pages.
• shared_gpa_output: Shared 4KB aligned GPA as output – the memory contains a Response. It could be more than one 4K pages.
• interrupt_vector: Event notification interrupt vector - (valid values 32~255) selected by TD. 0: blocking action. VMM need get response then return. 1~31: Reserved. Should not be used. 32~255: Non-block action. VMM can return immediately and signal the interrupt vector when the response is ready. VMM should inject interrupt vector into the TD VCPU that executed TDG.VP.VMCALL.
• time_out: Timeout– Maximum wait time for the command and response. 0 means infinite wait.