Re: [PATCH v3] x86/tdx: Dump TDX version During the TD Bootup

[Yi Sun]

On 03.10.2023 06:26, Kuppuswamy Sathyanarayanan wrote:
> On 9/30/2023 9:11 AM, Yi Sun wrote:
> > +static int tdg_get_sysinfo(struct tdg_sys_info *td_sys)
> > +{
> > +	struct tdx_module_output out;
> > +	u64 ret;
> > +
> > +	if (!td_sys)
> > +		return -EINVAL;
> > +
> > +	ret = __tdx_module_call(TDX_SYS_RD, 0, TDX_SYS_VENDOR_ID_FID, 0, 0,
> > +				&out);
> > +	if (TDCALL_RETURN_CODE(ret) == TDCALL_INVALID_OPERAND)
> > +		goto version_1_0;
> > +	else if (ret)
> > +		return ret;
>
> For this failure case, do you want to reset tdg_sys_info to some value like zero
> or some constants to specify unknown?
Yes, that would be better for this case.

> > +
> > +	td_sys->vendor_id = (u32)out.r8;
> > +
> > +	ret = __tdx_module_call(TDX_SYS_RD, 0, TDX_SYS_MAJOR_FID, 0, 0, &out);
> > +	if (ret)
> > +		return ret;
> > +
> > +	td_sys->major_version = (u16)out.r8;
> > +
> > +	ret = __tdx_module_call(TDX_SYS_RD, 0, TDX_SYS_MINOR_FID, 0, 0, &out);
> > +	if (ret)
> > +		return ret;
> > +
> > +	td_sys->minor_version = (u16)out.r8;
> > +
> > +	return 0;
> > +
> > +	/* TDX 1.0 does not have the TDCALL TDG.SYS.RD */
> > +version_1_0:
> > +	td_sys->vendor_id = TDX_VENDOR_INTEL;
> > +	td_sys->major_version = 1;
> > +	td_sys->minor_version = 0;
> > +
> > +	return 0;
> > +}
> > +
> >  void __init tdx_early_init(void)
> >  {
> >  	u64 cc_mask;
> >  	u32 eax, sig[3];
> > +	struct tdg_sys_info td_sys_info;
> >
> >  	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2],  &sig[1]);
> >
> > @@ -820,5 +882,9 @@ void __init tdx_early_init(void)
> >  	 */
> >  	x86_cpuinit.parallel_bringup = false;
> >
> > -	pr_info("Guest detected\n");
> > +	tdg_get_sysinfo(&td_sys_info);
>
> Why not check the return value before dumping the info?
I overlooked that. I will add it in the next version.
Thanks Sathya for your comments.

Thanks
     --Yi Sun