linux-kernel - Re: [PATCHv2 01/12] x86/tdx: Consolidate TDX error handling

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Message-ID: <5cfb2e09-7ecb-4144-9122-c11152b18b5e@intel.com>
Date: Wed, 25 Jun 2025 10:58:37 -0700
From: Dave Hansen <dave.hansen@...el.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
 pbonzini@...hat.com, seanjc@...gle.com, dave.hansen@...ux.intel.com
Cc: rick.p.edgecombe@...el.com, isaku.yamahata@...el.com,
 kai.huang@...el.com, yan.y.zhao@...el.com, chao.gao@...el.com,
 tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, kvm@...r.kernel.org,
 x86@...nel.org, linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2 01/12] x86/tdx: Consolidate TDX error handling

On 6/9/25 12:13, Kirill A. Shutemov wrote:
> Move all (host, kvm, guest) code related to TDX error handling into
> <asm/tdx_errno.h>.
> 
> Add inline functions to check errors.

I really prefer that code moves and introduction of new things be done
_separately_.

It's a lot easier to check for errors in the move when it's the on

...
>  	ret = __tdcall(TDG_MR_REPORT, &args);
>  	if (ret) {
> -		if (TDCALL_RETURN_CODE(ret) == TDCALL_INVALID_OPERAND)
> +		if (tdx_operand_invalid(ret))
>  			return -EINVAL;
>  		return -EIO;
>  	}

That said, the resulting code here is a lot nicer that what you started
with.

...
> -/*
> - * TDX module SEAMCALL leaf function error codes
> - */
> -#define TDX_SUCCESS		0ULL
> -#define TDX_RND_NO_ENTROPY	0x8000020300000000ULL

Kai, you were responsible for this nugget. What do you think of this patch?

> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -202,12 +202,6 @@ static DEFINE_MUTEX(tdx_lock);
>  
>  static atomic_t nr_configured_hkid;
>  
> -static bool tdx_operand_busy(u64 err)
> -{
> -	return (err & TDX_SEAMCALL_STATUS_MASK) == TDX_OPERAND_BUSY;
> -}
> -
> -

Isaku, this one was yours (along with the whitespace damage). What do
you think of this patch?