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Subject: Re: [PATCH v3 3/3] x86/acpi, x86/boot: Add multiprocessor wake-up
 support
To:     "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     Rafael J Wysocki <rjw@rjwysocki.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Len Brown <lenb@kernel.org>,
        Robert Moore <robert.moore@intel.com>,
        Erik Kaneda <erik.kaneda@intel.com>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        "open list:ACPI COMPONENT ARCHITECTURE (ACPICA)" <devel@acpica.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        the arch/x86 maintainers <x86@kernel.org>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Andi Kleen <ak@linux.intel.com>
References: <20210426023941.729334-1-sathyanarayanan.kuppuswamy@linux.intel.com>
 <20210426023941.729334-4-sathyanarayanan.kuppuswamy@linux.intel.com>
 <97e14cdc-ea98-18b8-0c89-db52440a7716@linux.intel.com>
 <CAJZ5v0gsqyXSr+Kw603333PZ=gnsBizNhyLAcu588OChEHT=AQ@mail.gmail.com>
From:   "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
Message-ID: <4fa40e7a-bcb2-db0f-8dc5-28728b14377d@linux.intel.com>
Date:   Mon, 10 May 2021 10:10:24 -0700
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On 5/10/21 9:55 AM, Rafael J. Wysocki wrote:
> I'm not sure how my comment regarding the fact that for a given CPU
> this function is only usable once has been addressed.
> 
> While it may not be a practical concern in the use case that you are
> after (TDX), this is a generic mechanism and it needs to cover other
> possible usage scenarios.

For the same CPU, if we try to use mailbox again, firmware will not
respond to it. So the command will timeout and return error.

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer