linux-kernel - Re: [PATCH v3 02/26] x86/virt/tdx: Use %# prefix for hex values in SEAMCALL error messages

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <35fa8047-7506-4a78-b493-732160c3d25c@linux.intel.com>
Date: Wed, 28 Jan 2026 09:34:03 +0800
From: Binbin Wu <binbin.wu@...ux.intel.com>
To: Chao Gao <chao.gao@...el.com>
Cc: linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org,
 kvm@...r.kernel.org, x86@...nel.org, reinette.chatre@...el.com,
 ira.weiny@...el.com, kai.huang@...el.com, dan.j.williams@...el.com,
 yilun.xu@...ux.intel.com, sagis@...gle.com, vannapurve@...gle.com,
 paulmck@...nel.org, nik.borisov@...e.com, zhenzhong.duan@...el.com,
 seanjc@...gle.com, rick.p.edgecombe@...el.com, kas@...nel.org,
 dave.hansen@...ux.intel.com, vishal.l.verma@...el.com,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v3 02/26] x86/virt/tdx: Use %# prefix for hex values in
 SEAMCALL error messages

On 1/23/2026 10:55 PM, Chao Gao wrote:
> "%#" format specifier automatically adds the "0x" prefix and has one less
> character than "0x%".
> 
> For conciseness, replace "0x%" with "%#" when printing hexadecimal values
> in SEAMCALL error messages.
> 
> Suggested-by: Dan Williams <dan.j.williams@...el.com>
> Signed-off-by: Chao Gao <chao.gao@...el.com>

Reviewed-by: Binbin Wu <binbin.wu@...ux.intel.com>

> ---
> "0x%" is also used to print TDMR ranges. I didn't convert them to reduce
> code churn, but if they should be converted for consistency, I'm happy
> to do that.

Generally, is there any preference for coding in Linux kernel about
"0x%" VS. "%#"? Or developers just make their own choices?

> 
> v2: new
> ---
>  arch/x86/virt/vmx/tdx/tdx.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index dbc7cb08ca53..2218bb42af40 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -63,16 +63,16 @@ typedef void (*sc_err_func_t)(u64 fn, u64 err, struct tdx_module_args *args);
>  
>  static inline void seamcall_err(u64 fn, u64 err, struct tdx_module_args *args)
>  {
> -	pr_err("SEAMCALL (%llu) failed: 0x%016llx\n", fn, err);
> +	pr_err("SEAMCALL (%llu) failed: %#016llx\n", fn, err);
>  }
>  
>  static inline void seamcall_err_ret(u64 fn, u64 err,
>  				    struct tdx_module_args *args)
>  {
>  	seamcall_err(fn, err, args);
> -	pr_err("RCX 0x%016llx RDX 0x%016llx R08 0x%016llx\n",
> +	pr_err("RCX %#016llx RDX %#016llx R08 %#016llx\n",
>  			args->rcx, args->rdx, args->r8);
> -	pr_err("R09 0x%016llx R10 0x%016llx R11 0x%016llx\n",
> +	pr_err("R09 %#016llx R10 %#016llx R11 %#016llx\n",
>  			args->r9, args->r10, args->r11);
>  }
>