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From:   Thomas Gleixner <tglx@linutronix.de>
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To:     Peter Zijlstra <peterz@infradead.org>,
        Kai Huang <kai.huang@intel.com>
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-mm@kvack.org, seanjc@google.com, pbonzini@redhat.com,
        dave.hansen@intel.com, dan.j.williams@intel.com,
        rafael.j.wysocki@intel.com, kirill.shutemov@linux.intel.com,
        ying.huang@intel.com, reinette.chatre@intel.com,
        len.brown@intel.com, tony.luck@intel.com, ak@linux.intel.com,
        isaku.yamahata@intel.com, chao.gao@intel.com,
        sathyanarayanan.kuppuswamy@linux.intel.com, bagasdotme@gmail.com,
        sagis@google.com, imammedo@redhat.com
Subject: Re: [PATCH v7 06/20] x86/virt/tdx: Shut down TDX module in case of
 error
In-Reply-To: <Y3yUdcJjrY2LhUWJ@hirez.programming.kicks-ass.net>
References: <cover.1668988357.git.kai.huang@intel.com>
 <48505089b645019a734d85c2c29f3c8ae2dbd6bd.1668988357.git.kai.huang@intel.com>
 <Y3yUdcJjrY2LhUWJ@hirez.programming.kicks-ass.net>
Date:   Tue, 22 Nov 2022 16:06:25 +0100
Message-ID: <87bkozgham.ffs@tglx>
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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