Re: [RFC PATCH v2 2/6] x86/sev: add SVSM vTPM probe/send_command functions

Stefano Garzarella
2025-03-10T13:59:53Z

On Mon, Mar 10, 2025 at 02:51:33PM +0100, Borislav Petkov wrote:
>On Mon, Mar 10, 2025 at 08:27:37AM -0500, Tom Lendacky wrote:
>> I don't think anything needs to be checked or printed.
>
>Yes.

Ack, I removed the check and the print.

@Boris I also removed `ret` to continue the slimming, so the end
result should be this:

bool snp_svsm_vtpm_probe(void)
{
struct svsm_call call = {};

/* The vTPM device is available only if a SVSM is present */
if (!snp_vmpl)
return false;

call.caa = svsm_get_caa();
call.rax = SVSM_VTPM_CALL(SVSM_VTPM_QUERY);

if (svsm_perform_call_protocol(&call))
return false;

/* Check platform commands contains TPM_SEND_COMMAND - platform command 8 */
return (call.rcx_out & BIT_ULL(8)) == BIT_ULL(8);
}

Quite nice, thanks for the review!
Stefano