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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 C0B87C433DB for ; Wed, 17 Feb 2021 01:04:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9638964E2F for ; Wed, 17 Feb 2021 01:04:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230375AbhBQBEL (ORCPT ); Tue, 16 Feb 2021 20:04:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229868AbhBQBEJ (ORCPT ); Tue, 16 Feb 2021 20:04:09 -0500 Received: from mail-pg1-x529.google.com (mail-pg1-x529.google.com [IPv6:2607:f8b0:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93300C061574 for ; Tue, 16 Feb 2021 17:03:27 -0800 (PST) Received: by mail-pg1-x529.google.com with SMTP id m2so7431518pgq.5 for ; Tue, 16 Feb 2021 17:03:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=qtwKaBiuPYUvz0xWl8m1S45ms1wew6GiKaYyXPstShY=; b=hR+6zsrZvmQI1jiLm98fGBSwoksg+qAfy20KAE1ORvWET6C9nkuhCS8n4UTgOAZKkv QObyw5pSdj33watWVnWiNP07EWbdZc74aX3ehGOZmjNbuJztbzqGFDJ06jB74mjrQ/pw GwWTJssT9ffcLgU021QHckdCmh/VNAyERhwRqiHu/8cN8bn6eYhGi6ba7zj1drC7Ohsl N/NZROd+s7fujzMa4Y/UxFsjQvwP02LO3CFyvFdXyiEVmhYr3K4QwyIWmcUIkeC7PwfT /wSZgn/cMzk70byBU5oQZGLzMpyCslk3pmdvj4l6poYtvj9ILOCqPptxG9q9b97JaxDH F97g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=qtwKaBiuPYUvz0xWl8m1S45ms1wew6GiKaYyXPstShY=; b=iUNuWLSPnPyZsAfdvc8mv0r6ZXcDr7ugP/C3WnT4N8yJbochqRj8uHUwNilEM+LKP8 ZqQVEgSe73pMS/CeylcfLtUN9r7dHKPoihID8BL9guvBeuihE/qVs5k6pLNRlMlXVNwn sSrroAkR7oGhASosWUpEauSjTmUVHyaH7wFb+wDPrqnqzsGl4OYCS99jhKcPqg2uJQBA BjEdYpKayJiYwoNl/G78tH7wfJl8KAEJfSvz77mF7spP8ZBoNjGtLYPJjr0EHLHcZ16X GL2aUdr1XExy29RRyYi18AkxG6ATesM0rY3WKyEBXt2DnEQF8pKN23HT6GlU+D6x8Qsf XjnA== X-Gm-Message-State: AOAM530oxjJQWGbc+RL7MWL0fSBvxkmk2W6mxRKV1DHTA8x+78+0Ynxe ufbdi944oHLbP2YA7ezYb1uGKA== X-Google-Smtp-Source: ABdhPJwjZFj3CFYYa4dEPkFYRXMEe77KR30ZgCJLDDPCSZBQF+i+bCpafGAOHWyio9En1S2D5oOqgg== X-Received: by 2002:a63:4e4c:: with SMTP id o12mr21708720pgl.143.1613523806692; Tue, 16 Feb 2021 17:03:26 -0800 (PST) Received: from google.com ([2620:15c:f:10:6948:259b:72c6:5517]) by smtp.gmail.com with ESMTPSA id v31sm308840pgl.76.2021.02.16.17.03.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Feb 2021 17:03:25 -0800 (PST) Date: Tue, 16 Feb 2021 17:03:19 -0800 From: Sean Christopherson To: Ashish Kalra Cc: pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, rkrcmar@redhat.com, joro@8bytes.org, bp@suse.de, thomas.lendacky@amd.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, srutherford@google.com, venu.busireddy@oracle.com, brijesh.singh@amd.com Subject: Re: [PATCH v10 10/16] KVM: x86: Introduce KVM_GET_SHARED_PAGES_LIST ioctl Message-ID: References: <7266edd714add8ec9d7f63eddfc9bbd4d789c213.1612398155.git.ashish.kalra@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7266edd714add8ec9d7f63eddfc9bbd4d789c213.1612398155.git.ashish.kalra@amd.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Feb 04, 2021, Ashish Kalra wrote: > From: Brijesh Singh > > The ioctl is used to retrieve a guest's shared pages list. What's the performance hit to boot time if KVM_HC_PAGE_ENC_STATUS is passed through to userspace? That way, userspace could manage the set of pages in whatever data structure they want, and these get/set ioctls go away. Also, aren't there plans for an in-guest migration helper? If so, do we have any idea what that interface will look like? E.g. if we're going to end up with a full fledged driver in the guest, why not bite the bullet now and bypass KVM entirely?