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=-13.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 E334AC4708F for ; Thu, 3 Jun 2021 02:32:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C11F3613E9 for ; Thu, 3 Jun 2021 02:32:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229692AbhFCCed (ORCPT ); Wed, 2 Jun 2021 22:34:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44900 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229541AbhFCCec (ORCPT ); Wed, 2 Jun 2021 22:34:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622687568; 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=taNtlOtsZUjAi05snNFgxAJ5niVmm5tsHS8sJiSNlCE=; b=G0HUITQFch1hYcKWOf0w1ElnqFdMgV5+vgODmyzY4yvFNOL9Ez8FoMd74j02CCHXTOrhim CMycSY99FxXexjt3x9tbUFjTD3Q2f6qLly+zJj6ZpP33M5T9OudBjTU2+NLEyKXB0GaIg4 EIu6pL/7pxP6LGWPaDaXEouNsJVmdQo= Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-509-vA9YtEHpP2OEaVTsdRflKg-1; Wed, 02 Jun 2021 22:32:47 -0400 X-MC-Unique: vA9YtEHpP2OEaVTsdRflKg-1 Received: by mail-pg1-f197.google.com with SMTP id w185-20020a6362c20000b02902208d90c8c8so2199223pgb.8 for ; Wed, 02 Jun 2021 19:32:47 -0700 (PDT) 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-transfer-encoding :content-language; bh=taNtlOtsZUjAi05snNFgxAJ5niVmm5tsHS8sJiSNlCE=; b=LdwfybSQ9MTnLKy1OPV0R/Jxs4zUnC3xXryiWVbo6AB5uRuRNzFgw25wsVM6fPaZTv 4PiRXFwG/M6qz3uSRIynqcXD6LnHQIF9j/3KxaalZVHakLtbFEKgBeAwfzmkZqp024LU j82EFRH8tvHkg45hsq9UufWNURfg2CQ2dw75mvow3YY+Slid6LzE3EjYURl1Jyf00Psc +CG/uDSUOF7HW3SIpGVPofrS7XWsL/NkiWPFNJ9+ji/TfPtVMFVmkFE0bwWRoTLP32tC oUm6s/XYDia1LPnO9ex5TL2zcYxlbh0JzgfjNxSM/nW05rqz7RHMg2Wg5PeIjQxica9y 1Olw== X-Gm-Message-State: AOAM531v0r8hfUOGUc0+oEIwBGByzDm8uYbGnOvzXyeTwdHtpy7n1N9C lj4F8qXRd2lTPE5WQr98Xxk2hpwJyp7M9bGq5wr4Q3I4bZLlNOYtgfWrmBNutzmQTAsZOzFfeAK fozF0GZSYzk6fHitXMBh+/bDMZTX9oCOZjtE5vHwiqLb9JL+UFvdVekCEj76nWMhYPfBtZ6vG6x Tj X-Received: by 2002:a62:7b50:0:b029:2ea:9298:1dcb with SMTP id w77-20020a627b500000b02902ea92981dcbmr2002620pfc.1.1622687566597; Wed, 02 Jun 2021 19:32:46 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwz6ep2t7jrZdGAehf8toVNlmui74UZ7cIZFq7uL7XUXGUiUUq0olnaswJvxVuevvgOPn0mCw== X-Received: by 2002:a62:7b50:0:b029:2ea:9298:1dcb with SMTP id w77-20020a627b500000b02902ea92981dcbmr2002593pfc.1.1622687566256; Wed, 02 Jun 2021 19:32:46 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id ip7sm520736pjb.39.2021.06.02.19.32.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Jun 2021 19:32:45 -0700 (PDT) Subject: Re: [PATCH v1 1/8] virtio: Force only split mode with protected guest To: Andi Kleen , mst@redhat.com Cc: virtualization@lists.linux-foundation.org, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, iommu@lists.linux-foundation.org, x86@kernel.org, sathyanarayanan.kuppuswamy@linux.intel.com, jpoimboe@redhat.com, linux-kernel@vger.kernel.org References: <20210603004133.4079390-1-ak@linux.intel.com> <20210603004133.4079390-2-ak@linux.intel.com> <28c8302b-6833-10b4-c0eb-67456e7c4069@redhat.com> <09e17c7f-ce51-1a46-72c4-12223bee4e3a@linux.intel.com> From: Jason Wang Message-ID: <1c08bc42-7448-351e-78bf-fcf68d2b2561@redhat.com> Date: Thu, 3 Jun 2021 10:32:40 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <09e17c7f-ce51-1a46-72c4-12223bee4e3a@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2021/6/3 上午9:48, Andi Kleen 写道: > >> So we will see huge performance regression without indirect >> descriptor. We need to consider to address this. > > A regression would be when some existing case would be slower. > > That's not the case because the behavior for the existing cases does > not change. > > Anyways when there are performance problems they can be addressed, but > first is to make it secure. I agree, but I want to know why indirect descriptor needs to be disabled. The table can't be wrote by the device since it's not coherent swiotlb mapping. Thanks > > -Andi > > >> >> Thanks >> >> >>>               break; >>>           case VIRTIO_RING_F_EVENT_IDX: >>>               break; >>> @@ -2231,9 +2240,12 @@ void vring_transport_features(struct >>> virtio_device *vdev) >>>           case VIRTIO_F_ACCESS_PLATFORM: >>>               break; >>>           case VIRTIO_F_RING_PACKED: >>> +            if (protected_guest_has(VM_MEM_ENCRYPT)) >>> +                goto clear; >>>               break; >>>           case VIRTIO_F_ORDER_PLATFORM: >>>               break; >>> +        clear: >>>           default: >>>               /* We don't understand this bit. */ >>>               __virtio_clear_bit(vdev, i); >> >