linux-kernel - Re: [PATCH v4 02/16] x86/tdx: Add helpers to check return status codes

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Message-ID: <86e2d5fa-4d68-4200-98d1-77113bc3c1da@linux.intel.com>
Date: Mon, 24 Nov 2025 16:56:15 +0800
From: Binbin Wu <binbin.wu@...ux.intel.com>
To: Rick Edgecombe <rick.p.edgecombe@...el.com>
Cc: bp@...en8.de, chao.gao@...el.com, dave.hansen@...el.com,
 isaku.yamahata@...el.com, kai.huang@...el.com, kas@...nel.org,
 kvm@...r.kernel.org, linux-coco@...ts.linux.dev,
 linux-kernel@...r.kernel.org, mingo@...hat.com, pbonzini@...hat.com,
 seanjc@...gle.com, tglx@...utronix.de, vannapurve@...gle.com,
 x86@...nel.org, yan.y.zhao@...el.com, xiaoyao.li@...el.com,
 binbin.wu@...el.com, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCH v4 02/16] x86/tdx: Add helpers to check return status
 codes



On 11/21/2025 8:51 AM, Rick Edgecombe wrote:
[...]
>
> diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
> index 7b2833705d47..167c5b273c40 100644
> --- a/arch/x86/coco/tdx/tdx.c
> +++ b/arch/x86/coco/tdx/tdx.c
> @@ -129,9 +129,9 @@ int tdx_mcall_get_report0(u8 *reportdata, u8 *tdreport)
>   
>   	ret = __tdcall(TDG_MR_REPORT, &args);
>   	if (ret) {
> -		if (TDCALL_RETURN_CODE(ret) == TDCALL_INVALID_OPERAND)
> +		if (IS_TDX_OPERAND_INVALID(ret))
>   			return -ENXIO;
> -		else if (TDCALL_RETURN_CODE(ret) == TDCALL_OPERAND_BUSY)
> +		else if (IS_TDX_OPERAND_BUSY(ret))
>   			return -EBUSY;
>   		return -EIO;
>   	}
> @@ -165,9 +165,9 @@ int tdx_mcall_extend_rtmr(u8 index, u8 *data)
>   
>   	ret = __tdcall(TDG_MR_RTMR_EXTEND, &args);
>   	if (ret) {
> -		if (TDCALL_RETURN_CODE(ret) == TDCALL_INVALID_OPERAND)
> +		if (IS_TDX_OPERAND_INVALID(ret))
>   			return -ENXIO;
> -		if (TDCALL_RETURN_CODE(ret) == TDCALL_OPERAND_BUSY)
> +		if (IS_TDX_OPERAND_BUSY(ret))

After the changes in tdx_mcall_get_report0() and tdx_mcall_extend_rtmr(), the
macros defined in arch/x86/coco/tdx/tdx.c can be removed:

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 7b2833705d47..f72b7dfdacd1 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -33,11 +33,6 @@
  #define VE_GET_PORT_NUM(e)     ((e) >> 16)
  #define VE_IS_IO_STRING(e)     ((e) & BIT(4))

-/* TDX Module call error codes */
-#define TDCALL_RETURN_CODE(a)  ((a) >> 32)
-#define TDCALL_INVALID_OPERAND 0xc0000100
-#define TDCALL_OPERAND_BUSY    0x80000200
-
  #define TDREPORT_SUBTYPE_0     0

  static atomic_long_t nr_shared;

>   			return -EBUSY;
>   		return -EIO;
>   	}
> @@ -316,7 +316,7 @@ static void reduce_unnecessary_ve(void)
>   {
>   	u64 err = tdg_vm_wr(TDCS_TD_CTLS, TD_CTLS_REDUCE_VE, TD_CTLS_REDUCE_VE);
>   
> -	if (err == TDX_SUCCESS)
> +	if (IS_TDX_SUCCESS(err))
>   		return;
>   
>   	/*
> diff --git a/arch/x86/include/asm/shared/tdx_errno.h b/arch/x86/include/asm/shared/tdx_errno.h
> index 3aa74f6a6119..e302aed31b50 100644
> --- a/arch/x86/include/asm/shared/tdx_errno.h
> +++ b/arch/x86/include/asm/shared/tdx_errno.h
> @@ -5,7 +5,7 @@
>   #include <asm/trapnr.h>
>   
>   /* Upper 32 bit of the TDX error code encodes the status */
> -#define TDX_SEAMCALL_STATUS_MASK		0xFFFFFFFF00000000ULL
> +#define TDX_STATUS_MASK				0xFFFFFFFF00000000ULL
>   
>   /*
>    * TDX SEAMCALL Status Codes
> @@ -54,4 +54,49 @@
>   #define TDX_OPERAND_ID_SEPT			0x92
>   #define TDX_OPERAND_ID_TD_EPOCH			0xa9
>   
> +#ifndef __ASSEMBLER__
> +#include <linux/bits.h>
> +#include <linux/types.h>
> +
> +static inline u64 TDX_STATUS(u64 err)
> +{
> +	return err & TDX_STATUS_MASK;
> +}

Should be tagged with __always_inline since it's used in noinstr range.

[...]