linux-kernel - Re: [PATCH v3 01/21] x86/virt/tdx: Detect SEAM

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Date:   Tue, 19 Apr 2022 15:38:42 +1200
From:   Kai Huang <kai.huang@...el.com>
To:     Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com, pbonzini@...hat.com, dave.hansen@...el.com,
        len.brown@...el.com, tony.luck@...el.com,
        rafael.j.wysocki@...el.com, reinette.chatre@...el.com,
        dan.j.williams@...el.com, peterz@...radead.org, ak@...ux.intel.com,
        kirill.shutemov@...ux.intel.com, isaku.yamahata@...el.com
Subject: Re: [PATCH v3 01/21] x86/virt/tdx: Detect SEAM


> > +
> > +static void detect_seam(struct cpuinfo_x86 *c)
> > +{
> 
> why not do this check directly in tdx_detect_cpu()?

The second patch will detect TDX KeyID too.  I suppose you are saying below is
better?

void tdx_detect_cpu(struct cpuinfo_x86 *c)
{
	if (c == &boot_cpu_data) {
		detect_seam_bsp(c);
		detect_tdx_keyids_bsp(c);
	} else {
		detect_seam_ap(c);
		detect_tdx_keyids_ap(c);
	}
}

I personally don't see how above is better than the current way.  Instead, I
think having SEAM and TDX KeyID detection code in single function respectively
is more flexible for future extension (if needed).


> 
> > +	if (c == &boot_cpu_data)
> > +		detect_seam_bsp(c);
> > +	else
> > +		detect_seam_ap(c);
> > +}
> > +
> > +void tdx_detect_cpu(struct cpuinfo_x86 *c)
> > +{
> > +	detect_seam(c);
> > +}
>