Re: [PATCH RFC 00/20] attestation: Add a common subsystem and TDX support

[Mimi Zohar <zohar@linux.ibm.com>]

On Tue, 2026-10-20 at 13:52 -0300, Jason Gunthorpe wrote:
> On Tue, Oct 20, 2026 at 05:11:03PM +0100, Yeoreum Yun wrote:
> > But, I have a related concern about deferred probing of RoT devices.
> > 
> > For example, if TPM probing is deferred until after the attestation
> > subsystem has been initialized, how would the subsystem handle the
> > TPM becoming available later (This is reason for
> > IMA_INIT_LATE_SYNC).

FYI, this patch set initializes at module_initcall(), not even late_initcall().

> I don't think it would be any different, the mechanism for TPM would
> become generalized and apply to any attestation driver.
> 
> This series doesn't attempt to do that flow yet, moving ima over and
> dealing with this is another series :)

When TPM device initialization is deferred, it is retried during
late_initcall().

As there is no way of ordering within an initcall level, there is a race between
the device driver probing and the call to late_initcall(). The solution was to
allow IMA to register at late_initcall_sync() based on a Kconfig.

Both device_initcall() and module_initcall() are at level 6. Are you sure:
• the PCIe SPDM Devices will be ready at module_initcall()?
• the PCIe SPDM Devices are not deferred to late_initcall()?

Mimi