linux-kernel - Re: [PATCH v3 04/12] x86/tdx: Rename __tdx_module_call() to _

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Date:   Fri, 28 Jul 2023 08:33:58 -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, isaku.yamahata@...el.com,
        n.borisov.lkml@...il.com
Subject: Re: [PATCH v3 04/12] x86/tdx: Rename __tdx_module_call() to
 __tdcall()



On 7/26/23 4:25 AM, Kai Huang wrote:
> __tdx_module_call() is only used by the TDX guest to issue TDCALL to the
> TDX module.  Rename it to __tdcall() to match its behaviour, e.g., it
> cannot be used to make host-side SEAMCALL.
> 
> Also rename tdx_module_call() which is a wrapper of __tdx_module_call()
> to tdcall().
> 
> No functional change intended.
> 
> Signed-off-by: Kai Huang <kai.huang@...el.com>
> ---

Looks fine to me.

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

> 
> v2 -> v3:
>  - No change.
> 
> v1 -> v2:
>  - Rebase to 6.5-rc2.
> 
> ---
>  arch/x86/coco/tdx/tdcall.S        | 10 +++++-----
>  arch/x86/coco/tdx/tdx-shared.c    |  2 +-
>  arch/x86/coco/tdx/tdx.c           | 18 +++++++++---------
>  arch/x86/include/asm/shared/tdx.h |  4 ++--
>  4 files changed, 17 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S
> index e5d4b7d8ecd4..6aebac08f2bf 100644
> --- a/arch/x86/coco/tdx/tdcall.S
> +++ b/arch/x86/coco/tdx/tdcall.S
> @@ -40,8 +40,8 @@
>  .section .noinstr.text, "ax"
>  
>  /*
> - * __tdx_module_call()  - Used by TDX guests to request services from
> - * the TDX module (does not include VMM services) using TDCALL instruction.
> + * __tdcall()  - Used by TDX guests to request services from the TDX
> + * module (does not include VMM services) using TDCALL instruction.
>   *
>   * Transforms function call register arguments into the TDCALL register ABI.
>   * After TDCALL operation, TDX module output is saved in @out (if it is
> @@ -62,7 +62,7 @@
>   *
>   *-------------------------------------------------------------------------
>   *
> - * __tdx_module_call() function ABI:
> + * __tdcall() function ABI:
>   *
>   * @fn  (RDI)          - TDCALL Leaf ID,    moved to RAX
>   * @rcx (RSI)          - Input parameter 1, moved to RCX
> @@ -77,9 +77,9 @@
>   *
>   * Return status of TDCALL via RAX.
>   */
> -SYM_FUNC_START(__tdx_module_call)
> +SYM_FUNC_START(__tdcall)
>  	TDX_MODULE_CALL host=0
> -SYM_FUNC_END(__tdx_module_call)
> +SYM_FUNC_END(__tdcall)
>  
>  /*
>   * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDCALL
> diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c
> index f10cd3e4a04e..90631abdac34 100644
> --- a/arch/x86/coco/tdx/tdx-shared.c
> +++ b/arch/x86/coco/tdx/tdx-shared.c
> @@ -35,7 +35,7 @@ static unsigned long try_accept_one(phys_addr_t start, unsigned long len,
>  	}
>  
>  	tdcall_rcx = start | page_size;
> -	if (__tdx_module_call(TDG_MEM_PAGE_ACCEPT, tdcall_rcx, 0, 0, 0, NULL))
> +	if (__tdcall(TDG_MEM_PAGE_ACCEPT, tdcall_rcx, 0, 0, 0, NULL))
>  		return 0;
>  
>  	return accept_size;
> diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
> index 05785df66b1c..8c13944925e3 100644
> --- a/arch/x86/coco/tdx/tdx.c
> +++ b/arch/x86/coco/tdx/tdx.c
> @@ -66,10 +66,10 @@ EXPORT_SYMBOL_GPL(tdx_kvm_hypercall);
>   * should only be used for calls that have no legitimate reason to fail
>   * or where the kernel can not survive the call failing.
>   */
> -static inline void tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
> -				   struct tdx_module_output *out)
> +static inline void tdcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
> +			  struct tdx_module_output *out)
>  {
> -	if (__tdx_module_call(fn, rcx, rdx, r8, r9, out))
> +	if (__tdcall(fn, rcx, rdx, r8, r9, out))
>  		panic("TDCALL %lld failed (Buggy TDX module!)\n", fn);
>  }
>  
> @@ -91,9 +91,9 @@ int tdx_mcall_get_report0(u8 *reportdata, u8 *tdreport)
>  {
>  	u64 ret;
>  
> -	ret = __tdx_module_call(TDG_MR_REPORT, virt_to_phys(tdreport),
> -				virt_to_phys(reportdata), TDREPORT_SUBTYPE_0,
> -				0, NULL);
> +	ret = __tdcall(TDG_MR_REPORT, virt_to_phys(tdreport),
> +			virt_to_phys(reportdata), TDREPORT_SUBTYPE_0,
> +			0, NULL);
>  	if (ret) {
>  		if (TDCALL_RETURN_CODE(ret) == TDCALL_INVALID_OPERAND)
>  			return -EINVAL;
> @@ -152,7 +152,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask)
>  	 * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL
>  	 * [TDG.VP.INFO].
>  	 */
> -	tdx_module_call(TDG_VP_INFO, 0, 0, 0, 0, &out);
> +	tdcall(TDG_VP_INFO, 0, 0, 0, 0, &out);
>  
>  	/*
>  	 * The highest bit of a guest physical address is the "sharing" bit.
> @@ -594,7 +594,7 @@ void tdx_get_ve_info(struct ve_info *ve)
>  	 * Note, the TDX module treats virtual NMIs as inhibited if the #VE
>  	 * valid flag is set. It means that NMI=>#VE will not result in a #DF.
>  	 */
> -	tdx_module_call(TDG_VP_VEINFO_GET, 0, 0, 0, 0, &out);
> +	tdcall(TDG_VP_VEINFO_GET, 0, 0, 0, 0, &out);
>  
>  	/* Transfer the output parameters */
>  	ve->exit_reason = out.rcx;
> @@ -774,7 +774,7 @@ void __init tdx_early_init(void)
>  	cc_set_mask(cc_mask);
>  
>  	/* Kernel does not use NOTIFY_ENABLES and does not need random #VEs */
> -	tdx_module_call(TDG_VM_WR, 0, TDCS_NOTIFY_ENABLES, 0, -1ULL, NULL);
> +	tdcall(TDG_VM_WR, 0, TDCS_NOTIFY_ENABLES, 0, -1ULL, NULL);
>  
>  	/*
>  	 * All bits above GPA width are reserved and kernel treats shared bit
> diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h
> index 78f109446da6..9e3699b751ef 100644
> --- a/arch/x86/include/asm/shared/tdx.h
> +++ b/arch/x86/include/asm/shared/tdx.h
> @@ -88,8 +88,8 @@ struct tdx_module_output {
>  };
>  
>  /* Used to communicate with the TDX module */
> -u64 __tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
> -		      struct tdx_module_output *out);
> +u64 __tdcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
> +	     struct tdx_module_output *out);
>  
>  bool tdx_accept_memory(phys_addr_t start, phys_addr_t end);
>  

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer