linux-kernel - Re: [PATCH 03/10] x86/tdx: Move FRAME_BEGIN/END to TDX_MODULE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5961fe40-7716-c0fe-b399-f3f2bf39b562@linux.intel.com>
Date:   Wed, 12 Jul 2023 12:57:52 -0700
From:   Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Kai Huang <kai.huang@...el.com>, peterz@...radead.org,
        kirill.shutemov@...ux.intel.com, linux-kernel@...r.kernel.org
Cc:     dave.hansen@...el.com, tglx@...utronix.de, bp@...en8.de,
        mingo@...hat.com, hpa@...or.com, x86@...nel.org, seanjc@...gle.com,
        pbonzini@...hat.com, kvm@...r.kernel.org, isaku.yamahata@...el.com
Subject: Re: [PATCH 03/10] x86/tdx: Move FRAME_BEGIN/END to TDX_MODULE_CALL
 asm macro



On 7/12/23 1:55 AM, Kai Huang wrote:
> Currently, the TDX_MODULE_CALL asm macro and the __tdx_module_call()
> take registers directly as input and a 'struct tdx_module_output' as
> optional output.  This is different from the __tdx_hypercall(), which
> simply uses a structure to carry all input/output.  There's no point to
> leave __tdx_module_call() complicated as it is.
> 
> As a preparation to simplify the __tdx_module_call() to make it look
> like __tdx_hypercall(), move FRAME_BEGIN/END and RET from the
> __tdx_module_call() to the TDX_MODULE_CALL assembly macro.  This also
> allows more implementation flexibility of the assembly inside the
> TDX_MODULE_CALL macro, e.g., allowing putting an _ASM_EXTABLE() after
> the main body of the assembly.
> 
> This is basically based on Peter's code.
> 
> Cc: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Suggested-by: Peter Zijlstra <peterz@...radead.org>
> Signed-off-by: Kai Huang <kai.huang@...el.com>
> ---

Looks fine to me.

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>

>  arch/x86/coco/tdx/tdcall.S      | 3 ---
>  arch/x86/virt/vmx/tdx/tdxcall.S | 5 +++++
>  2 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S
> index 2eca5f43734f..e5d4b7d8ecd4 100644
> --- a/arch/x86/coco/tdx/tdcall.S
> +++ b/arch/x86/coco/tdx/tdcall.S
> @@ -78,10 +78,7 @@
>   * Return status of TDCALL via RAX.
>   */
>  SYM_FUNC_START(__tdx_module_call)
> -	FRAME_BEGIN
>  	TDX_MODULE_CALL host=0
> -	FRAME_END
> -	RET
>  SYM_FUNC_END(__tdx_module_call)
>  
>  /*
> diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcall.S
> index 3524915d8bd9..b5ab919c7fa8 100644
> --- a/arch/x86/virt/vmx/tdx/tdxcall.S
> +++ b/arch/x86/virt/vmx/tdx/tdxcall.S
> @@ -1,5 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0 */
>  #include <asm/asm-offsets.h>
> +#include <asm/frame.h>
>  #include <asm/tdx.h>
>  
>  /*
> @@ -18,6 +19,7 @@
>   *            TDX module.
>   */
>  .macro TDX_MODULE_CALL host:req
> +	FRAME_BEGIN
>  	/*
>  	 * R12 will be used as temporary storage for struct tdx_module_output
>  	 * pointer. Since R12-R15 registers are not used by TDCALL/SEAMCALL
> @@ -91,4 +93,7 @@
>  .Lno_output_struct:
>  	/* Restore the state of R12 register */
>  	pop %r12
> +
> +	FRAME_END
> +	RET
>  .endm

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer