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[23.128.96.18]) by mx.google.com with ESMTP id a8si4990336ejc.334.2021.05.10.10.25.15; Mon, 10 May 2021 10:25:39 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231270AbhEJRYt (ORCPT + 99 others); Mon, 10 May 2021 13:24:49 -0400 Received: from mail-ot1-f42.google.com ([209.85.210.42]:41478 "EHLO mail-ot1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232771AbhEJRYU (ORCPT ); Mon, 10 May 2021 13:24:20 -0400 Received: by mail-ot1-f42.google.com with SMTP id 36-20020a9d0ba70000b02902e0a0a8fe36so8797821oth.8; Mon, 10 May 2021 10:23:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=YYGVy1dBjcY+gobayJq/B1W7IwBp6P5SIbqRmJkMD80=; b=niaDWqWKFas1GwpIPTLZAdbqAs1bUF7VzwmJ+Q447EaxxnLWInU9kv6vhZ2N5RBRJh hFSox+jCfVte0+smm5RM+2fjMNqNIkO/befsfGum6BB5wpgNGBdtlqeJlnom8CenMS4M qr7s/VSzGkqNhqm2S4dmcV/9M0e8GlYnKR8BAMyzpT5C2Lb0r+wZ+hWyEFeDB0bjgNXs 5/sqvO7THu7a8WCvOd2fe3otg6qqXGPqkFx2kblbfKHMKHqfXVoWnmeLRcoRlCK57tFY 9nHtq+VoNmZr/cHLg0wnuNsfg0fVrRLfzI4vgYI1KxhOsIhzRE3R4fgCAafj8zUFUD2g opgQ== X-Gm-Message-State: AOAM530p4LM6NIO33EgUcoj8SeH6v8xOJ/SW+6hRQ3lk1PJfgKytemnj 4Pc0lTs2luAcXiclJ+uUZe6aSZ4HQIHDnDrpoHE= X-Received: by 2002:a9d:5a7:: with SMTP id 36mr22485830otd.321.1620667393829; Mon, 10 May 2021 10:23:13 -0700 (PDT) MIME-Version: 1.0 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> <4fa40e7a-bcb2-db0f-8dc5-28728b14377d@linux.intel.com> In-Reply-To: <4fa40e7a-bcb2-db0f-8dc5-28728b14377d@linux.intel.com> From: "Rafael J. Wysocki" Date: Mon, 10 May 2021 19:23:02 +0200 Message-ID: Subject: Re: [PATCH v3 3/3] x86/acpi, x86/boot: Add multiprocessor wake-up support To: "Kuppuswamy, Sathyanarayanan" Cc: "Rafael J. Wysocki" , Rafael J Wysocki , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , Len Brown , Robert Moore , Erik Kaneda , ACPI Devel Maling List , "open list:ACPI COMPONENT ARCHITECTURE (ACPICA)" , Linux Kernel Mailing List , "the arch/x86 maintainers" , Sean Christopherson , Andi Kleen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 10, 2021 at 7:10 PM Kuppuswamy, Sathyanarayanan wrote: > > > > 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. Well, theoretically, but what if it checks the mailbox every time for all CPUs? Or similar? > So the command will timeout and return error. If the firmware behaves as expected, but what if it doesn't?