linux-kernel - Re: [RFC v2-fix-v2 1/1] x86/boot: Avoid #VE during boot for TDX platforms

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Date:   Fri, 21 May 2021 11:32:36 -0700
From:   "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Dave Hansen <dave.hansen@...el.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Tony Luck <tony.luck@...el.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kirill Shutemov <kirill.shutemov@...ux.intel.com>,
        Kuppuswamy Sathyanarayanan <knsathya@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Raj Ashok <ashok.raj@...el.com>, linux-kernel@...r.kernel.org,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: Re: [RFC v2-fix-v2 1/1] x86/boot: Avoid #VE during boot for TDX
 platforms



On 5/21/21 11:30 AM, Dave Hansen wrote:
> That sounds sane to me.  It would be nice to get this into the
> changelog.  Perhaps:
> 
> 	This theoretically makes guest boot more fragile.  If, for
> 	instance, EER was set up incorrectly and a WRMSR was performed,
> 	the resulting (unhandled) #VE would triple fault.  However, this
> 	is likely to trip up the guest BIOS long before control reaches
> 	the kernel.  In any case, these kinds of problems are unlikely
> 	to occur in production environments, and developers have good
> 	debug tools to fix them quickly.
> 
> That would put my mind at ease a bit.

I can add it to change log.

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer