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Date:   Tue, 30 May 2023 15:29:51 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Tom Lendacky <thomas.lendacky@amd.com>
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Subject: Re: [patch] x86/smpboot: Disable parallel bootup if cc_vendor != NONE
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On Tue, May 30, 2023 at 02:09:17PM +0200, Thomas Gleixner wrote:
> The decision to allow parallel bringup of secondary CPUs checks
> CC_ATTR_GUEST_STATE_ENCRYPT to detect encrypted guests. Those cannot use
> parallel bootup because accessing the local APIC is intercepted and raises
> a #VC or #VE, which cannot be handled at that point.
> 
> The check works correctly, but only for AMD encrypted guests. TDX does not
> set that flag.
> 
> Check for cc_vendor != CC_VENDOR_NONE instead. That might be overbroad, but
> definitely works for both AMD and Intel.

It boots fine with TDX, but I think it is wrong. cc_get_vendor() will
report CC_VENDOR_AMD even on bare metal if SME is enabled. I don't think
we want it.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov