linux-kernel - Re: [RFC v2-fix-v2 1/1] x86: Introduce generic protected guest abstraction

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Message-ID: <82f9e5a9-682a-70be-e5ea-938bb742265f@linux.intel.com>
Date:   Mon, 7 Jun 2021 11:01:05 -0700
From:   "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...el.com>,
        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>,
        Sean Christopherson <seanjc@...gle.com>,
        linux-kernel@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [RFC v2-fix-v2 1/1] x86: Introduce generic protected guest
 abstraction



On 6/3/21 11:14 AM, Borislav Petkov wrote:
> On Tue, Jun 01, 2021 at 02:14:17PM -0700, Kuppuswamy Sathyanarayanan wrote:

snip

> diff --git a/include/linux/protected_guest.h b/include/linux/protected_guest.h
> index 6855d5b3e244..bb4b1a06b21f 100644
> --- a/include/linux/protected_guest.h
> +++ b/include/linux/protected_guest.h
> @@ -2,7 +2,9 @@
>   #ifndef _LINUX_PROTECTED_GUEST_H
>   #define _LINUX_PROTECTED_GUEST_H 1
>   
> -#include <linux/mem_encrypt.h>
> +#include <asm/processor.h>
> +#include <asm/tdx.h>
> +#include <asm/sev.h>
>   
>   /* Protected Guest Feature Flags (leave 0-0xff for arch specific flags) */
>   
> @@ -20,23 +22,18 @@
>   #define VM_DISABLE_UNCORE_SUPPORT	0x105
>   
>   #if defined(CONFIG_INTEL_TDX_GUEST) || defined(CONFIG_AMD_MEM_ENCRYPT)
> -
> -#include <asm/tdx.h>
> -

Why move this header outside CONFIG_INTEL_TDX_GUEST or CONFIG_AMD_MEM_ENCRYPT ifdef?

This header only exists in x86 arch code. So it is better to protect it with x86
specific header file.

>   static inline bool protected_guest_has(unsigned long flag)
>   {
>   	if (is_tdx_guest())
>   		return tdx_protected_guest_has(flag);
> -	else if (mem_encrypt_active())
> -		return amd_protected_guest_has(flag);
> +	else if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
> +		return sev_protected_guest_has(flag);
>   
>   	return false;
>   }
>   
>   #else
> -
>   static inline bool protected_guest_has(unsigned long flag) { return false; }
> -
>   #endif
>   
> -#endif
> +#endif /* _LINUX_PROTECTED_GUEST_H */
> 
> 

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer