Re: [PATCH v5 3/5] x86/tdx: Add tdx_mcall_extend_rtmr() interface

Dave Hansen
2025-05-01T17:28:09Z

On 4/24/25 13:12, Cedric Xing wrote:
> The TDX guest exposes one MRTD (Build-time Measurement Register) and four
> RTMR (Run-time Measurement Register) registers to record the build and boot
> measurements of a virtual machine (VM). These registers are similar to PCR
> (Platform Configuration Register) registers in the TPM (Trusted Platform
> Module) space. This measurement data is used to implement security features
> like attestation and trusted boot.
>
> To facilitate updating the RTMR registers, the TDX module provides support
> for the `TDG.MR.RTMR.EXTEND` TDCALL which can be used to securely extend
> the RTMR registers.
>
> Add helper function to update RTMR registers. It will be used by the TDX
> guest driver in enabling RTMR extension support.

Thank you for revising the changelogs to make the underlying purpose of
this series more clear.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>