Re: [PATCH v3 05/21] x86/virt/tdx: Detect P-SEAMLDR and TDX module

From: Kai Huang
Date: Tue Apr 26 2022 - 20:01:35 EST

On Tue, 2022-04-26 at 13:56 -0700, Dave Hansen wrote:
> On 4/5/22 21:49, Kai Huang wrote:
> > The P-SEAMLDR (persistent SEAM loader) is the first software module that
> > runs in SEAM VMX root, responsible for loading and updating the TDX
> > module. Both the P-SEAMLDR and the TDX module are expected to be loaded
> > before host kernel boots.
> Why bother with the P-SEAMLDR here at all? The kernel isn't loading the
> TDX module in this series. Why not just call into the TDX module directly?

It's not absolutely needed in this series. I choose to detect P-SEAMLDR because
detecting it can also detect the TDX module, and eventually we will need to
support P-SEAMLDR because the TDX module runtime update uses P-SEAMLDR's
SEAMCALL to do that.

Also, even for this series, detecting the P-SEAMLDR allows us to provide the P-
SEAMLDR information to user at a basic level in dmesg:

[..] tdx: P-SEAMLDR: version 0x0, vendor_id: 0x8086, build_date: 20211209,
build_num 160, major 1, minor 0

This may be useful to users, but it's not a hard requirement for this series.