linux-kernel - Re: [PATCH v2 13/21] x86/virt/seamldr: Abort updates if errors occurred midway

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: <aWdymkCJrSG+zMfz@yilunxu-OptiPlex-7050>
Date: Wed, 14 Jan 2026 18:40:26 +0800
From: Xu Yilun <yilun.xu@...ux.intel.com>
To: Chao Gao <chao.gao@...el.com>
Cc: linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org,
	x86@...nel.org, reinette.chatre@...el.com, ira.weiny@...el.com,
	kai.huang@...el.com, dan.j.williams@...el.com, sagis@...gle.com,
	vannapurve@...gle.com, paulmck@...nel.org, nik.borisov@...e.com,
	Farrah Chen <farrah.chen@...el.com>,
	"Kirill A. Shutemov" <kas@...nel.org>,
	Dave Hansen <dave.hansen@...ux.intel.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 v2 13/21] x86/virt/seamldr: Abort updates if errors
 occurred midway

On Tue, Sep 30, 2025 at 07:52:57PM -0700, Chao Gao wrote:
> The TDX Module update process has multiple stages, each of which may
> encounter failures.
> 
> The current state machine of updates proceeds to the next stage
> regardless of errors. But continuing updates when errors occur midway
> is pointless.
> 
> Add support of transitioning directly to the final stage on errors,
> effectively aborting the update and skipping all remaining stages.
> 
> Signed-off-by: Chao Gao <chao.gao@...el.com>
> Tested-by: Farrah Chen <farrah.chen@...el.com>
> ---
>  arch/x86/virt/vmx/tdx/seamldr.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c
> index b074630d42e3..fca558b90f72 100644
> --- a/arch/x86/virt/vmx/tdx/seamldr.c
> +++ b/arch/x86/virt/vmx/tdx/seamldr.c
> @@ -235,6 +235,7 @@ enum tdp_state {
>  static struct {
>  	enum tdp_state state;
>  	atomic_t thread_ack;
> +	atomic_t failed;
>  } tdp_data;
>  
>  static void set_target_state(enum tdp_state state)
> @@ -249,8 +250,16 @@ static void set_target_state(enum tdp_state state)
>  /* Last one to ack a state moves to the next state. */
>  static void ack_state(void)
>  {
> -	if (atomic_dec_and_test(&tdp_data.thread_ack))
> -		set_target_state(tdp_data.state + 1);
> +	if (atomic_dec_and_test(&tdp_data.thread_ack)) {
> +		/*
> +		 * If an error occurred, abort the update by skipping to
> +		 * the final state
> +		 */
> +		if (atomic_read(&tdp_data.failed))
> +			set_target_state(TDP_DONE);

Could we immediately move to TDP_DONE once the error happens, i.e. no
need to get all ack for current state?

> +		else
> +			set_target_state(tdp_data.state + 1);
> +	}
>  }

----8<-----
  static void ack_state(void)
  {
        if (atomic_read(&tdp_data.failed)) {
                set_target_state(TDP_DONE);
		return;
	}

        if (atomic_dec_and_test(&tdp_data.thread_ack))
                 set_target_state(tdp_data.state + 1);
  }