linux-kernel - Re: [PATCH v7 06/20] x86/virt/tdx: Shut down TDX module in case of error

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Message-ID: <87bkozgham.ffs@tglx>
Date:   Tue, 22 Nov 2022 16:06:25 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Peter Zijlstra <peterz@...radead.org>,
        Kai Huang <kai.huang@...el.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        linux-mm@...ck.org, seanjc@...gle.com, pbonzini@...hat.com,
        dave.hansen@...el.com, dan.j.williams@...el.com,
        rafael.j.wysocki@...el.com, kirill.shutemov@...ux.intel.com,
        ying.huang@...el.com, reinette.chatre@...el.com,
        len.brown@...el.com, tony.luck@...el.com, ak@...ux.intel.com,
        isaku.yamahata@...el.com, chao.gao@...el.com,
        sathyanarayanan.kuppuswamy@...ux.intel.com, bagasdotme@...il.com,
        sagis@...gle.com, imammedo@...hat.com
Subject: Re: [PATCH v7 06/20] x86/virt/tdx: Shut down TDX module in case of
 error

On Tue, Nov 22 2022 at 10:20, Peter Zijlstra wrote:

> On Mon, Nov 21, 2022 at 01:26:28PM +1300, Kai Huang wrote:
>
>> Shutting down the TDX module requires calling TDH.SYS.LP.SHUTDOWN on all
>> BIOS-enabled CPUs, and the SEMACALL can run concurrently on different
>> CPUs.  Implement a mechanism to run SEAMCALL concurrently on all online
>> CPUs and use it to shut down the module.  Later logical-cpu scope module
>> initialization will use it too.
>
> Uhh, those requirements ^ are not met by this:

  Can run concurrently != Must run concurrently
 
The documentation clearly says "can run concurrently" as quoted above.

Thanks,

        tglx