From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0276C433E0 for ; Thu, 25 Feb 2021 20:39:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96C026148E for ; Thu, 25 Feb 2021 20:39:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233403AbhBYUjS (ORCPT ); Thu, 25 Feb 2021 15:39:18 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:33566 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232403AbhBYUib (ORCPT ); Thu, 25 Feb 2021 15:38:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614285424; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=A2DCIpl4t4oP1eDrLAD1K46exhLy3YbNX0Rf8/i1+pw=; b=LJzpCz5teZdwEkeNMvWh60Qf+GJF/P3tj7/NT3imj3zGphx9VjH3+nQ1gpslrIsM6hY50c f/otw9HxRtliF1iAOxFsock+bgds8lOrhu9QwY21QXmlwrnXrw1jmwgL2dbPEPrBH3fJG2 UzoIZGk2XM6aKwJI8k927r2FcfIMyOg= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-597-gVstCY3IMSi6o99jb2iDgQ-1; Thu, 25 Feb 2021 15:37:02 -0500 X-MC-Unique: gVstCY3IMSi6o99jb2iDgQ-1 Received: by mail-wr1-f71.google.com with SMTP id h30so3601750wrh.10 for ; Thu, 25 Feb 2021 12:37:01 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=A2DCIpl4t4oP1eDrLAD1K46exhLy3YbNX0Rf8/i1+pw=; b=KJBnqBX97lIOkNm+O2a9OBf/zU030gfYOzlUqdxr/7yP9OF8cyjBLcKpPQ86Xm07zs XG4Wwf5JmjwPvpXof2T7SPnu855X+ZWQumXFMLaZ+kUCqBiCnW/DKkF6Wdcq8BLPI7Lm EckRYpVvZ4xTgx9/BeYFeutlisxeLCoZHA0Cnt6xN4BAEBnIQ5vcS+MuuhqI4aJznUlt pY3IqoS5I5/fUWIMUhxUuw4i/H4EXc+Bh8t/bPp7UArr8PzA/7XEor17ztxg2m0l0leY 1cFos+As+iXIR6LoggGvjTrPkpkL6dPc77kJNszsyC8VefzgVV/U0ZmPUL7kGmPDO0tH h/Hg== X-Gm-Message-State: AOAM532vZ//JRdcb4V0QF3D2Gg3i0N9fGrSZFhnjYD0h4EMKvl2O4On5 Vs9xOCqCOVaU4UbR4emAcBhA1GP2Lb+8JY/dHXYUVQGltvD0YNETEa60bTqJpcdW4XDb6Hy9fYS HstKINbPgldLh X-Received: by 2002:a05:600c:4f46:: with SMTP id m6mr158746wmq.154.1614285421009; Thu, 25 Feb 2021 12:37:01 -0800 (PST) X-Google-Smtp-Source: ABdhPJwXZvXWhSI3vb50fZVQvv9A84mo6VgUnsNq9wE8PRfGBQ3ihQ561J2mp2VhvnoXByW5vkEnvA== X-Received: by 2002:a05:600c:4f46:: with SMTP id m6mr158729wmq.154.1614285420836; Thu, 25 Feb 2021 12:37:00 -0800 (PST) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id o3sm3000691wmq.46.2021.02.25.12.36.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 25 Feb 2021 12:36:59 -0800 (PST) Subject: Re: [RFC] KVM: x86: Support KVM VMs sharing SEV context To: James Bottomley , natet@google.com Cc: Ashish.Kalra@amd.com, brijesh.singh@amd.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, rientjes@google.com, seanjc@google.com, srutherford@google.com, thomas.lendacky@amd.com, x86@kernel.org, Tobin Feldman-Fitzthum , DOV MURIK References: <7cb132ce522728f7689618832a65e31e37788201.camel@HansenPartnership.com> From: Paolo Bonzini Message-ID: <0b194254-1774-e54f-b801-c2d0c0ead07c@redhat.com> Date: Thu, 25 Feb 2021 21:36:58 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <7cb132ce522728f7689618832a65e31e37788201.camel@HansenPartnership.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 25/02/21 18:53, James Bottomley wrote: > > https://lore.kernel.org/qemu-devel/8b824c44-6a51-c3a7-6596-921dc47fea39@linux.ibm.com/ > > It sounds like this mechanism can be used to boot a vCPU through a > mirror VM after the fact, which is very compatible with the above whose > mechanism is simply to steal a VCPU to hold in reset until it's > activated. Yes, and it's much cleaner because, for example, the extra vCPU need not participate in the ACPI hotplug stuff and can even use a simplified run loop. Paolo