linux-kernel - Re: [PATCHv5.2 04/30] x86/tdx: Extend the confidential computing API to support TDX guests

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Message-ID: <YjDr1F+/xVAtOAKv@zn.tnic>
Date:   Tue, 15 Mar 2022 20:41:08 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc:     dave.hansen@...el.com, aarcange@...hat.com, ak@...ux.intel.com,
        brijesh.singh@....com, dan.j.williams@...el.com, david@...hat.com,
        hpa@...or.com, jgross@...e.com, jmattson@...gle.com,
        joro@...tes.org, jpoimboe@...hat.com, knsathya@...nel.org,
        linux-kernel@...r.kernel.org, luto@...nel.org, mingo@...hat.com,
        pbonzini@...hat.com, peterz@...radead.org,
        sathyanarayanan.kuppuswamy@...ux.intel.com, sdeep@...are.com,
        seanjc@...gle.com, tglx@...utronix.de, thomas.lendacky@....com,
        tony.luck@...el.com, vkuznets@...hat.com, wanpengli@...cent.com,
        x86@...nel.org
Subject: Re: [PATCHv5.2 04/30] x86/tdx: Extend the confidential computing API
 to support TDX guests

On Thu, Mar 10, 2022 at 02:51:21AM +0300, Kirill A. Shutemov wrote:
> diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
> index fc1365dd927e..6529db059938 100644
> --- a/arch/x86/coco/core.c
> +++ b/arch/x86/coco/core.c
> @@ -87,9 +87,18 @@ EXPORT_SYMBOL_GPL(cc_platform_has);
>  
>  u64 cc_mkenc(u64 val)
>  {
> +	/*
> +	 * Both AMD and Intel use a bit in page table to indicate encryption

"... a bit in the page table ..."

> +	 * status of the page.
> +	 *
> +	 * - for AMD, bit *set* means the page is encrypted
> +	 * - for Intel *clear* means encrypted.
> +	 */
>  	switch (vendor) {
>  	case CC_VENDOR_AMD:
>  		return val | cc_mask;
> +	case CC_VENDOR_INTEL:
> +		return val & ~cc_mask;
>  	default:
>  		return val;
>  	}

With that fixed:

Reviewed-by: Borislav Petkov <bp@...e.de>

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette