From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C9E3F370 for ; Tue, 30 May 2023 00:16:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685405809; 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=cBl3q2i812Jlu/HY8zePZKnZZJeg4miQ7XeIUUOuIUs=; b=EC8IjAlaEJeGBXv9msEe2PdkvOHjVXRikyqJlItGhZoe36YjqmxzdlK8Xusjb+bAPiqU1d Pd9R5CwwQwv14isZMokhEHJtOQjvrhAPxvS1sHuCbIeSEv2NQf3GNmqS4NICocYOWj0MWH gtau7H3FlWceDAlkbuGcACATVJVvFhI= Received: from mail-il1-f200.google.com (mail-il1-f200.google.com [209.85.166.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-614-XCPfqzsBPIK4knEzwBELSA-1; Mon, 29 May 2023 20:16:48 -0400 X-MC-Unique: XCPfqzsBPIK4knEzwBELSA-1 Received: by mail-il1-f200.google.com with SMTP id e9e14a558f8ab-33b59d59193so20320095ab.0 for ; Mon, 29 May 2023 17:16:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685405807; x=1687997807; h=content-transfer-encoding:mime-version:organization:references :in-reply-to:message-id:subject:cc:to:from:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=cBl3q2i812Jlu/HY8zePZKnZZJeg4miQ7XeIUUOuIUs=; b=iFjwVIpHKMfXiGOskeArqWTcFca/AyHxlrB/jPcj3CRQLnmj88wlxfnFE4ICOnkhv9 BPFMhzDK2q3vh5wdaUcNR+jN3KGoHBWx4urYqbu7VdNUbJGlor2IJLl6iXPZevdXo6Sy 9owq0UVRn2zJHWH35kLLs/8vY4uCjVnArHM6n2/43OLLPk3Af56h2LI3fdA41XeQp2jH 35orLJbWamSYiwHRahyU8ByHtIuNIcVfsnqVEMuUfosRg4/g9q985wxYCyajwStai3W9 wTfwIN/LZaauLfWXqoIfyZiBYntzwgdO1rfsLPhSQuL0EAWrcRnLp3NZa0JMPxnGld0B YmPw== X-Gm-Message-State: AC+VfDy2SmWPFg9FvE8P4Mg0CiZVXmPgIUoaqXOPpXP/OWUyiN0SWzTz iXU+kRntyiF4pXXK8kJvztgyyqyWhHBXOktw51F3ejHg+wJqUYa/TTJ2mpdv20rCfxMFExzjDvv nHd6PdVK6T2OwpnQ= X-Received: by 2002:a92:dcc1:0:b0:328:8770:b9c2 with SMTP id b1-20020a92dcc1000000b003288770b9c2mr507365ilr.14.1685405807098; Mon, 29 May 2023 17:16:47 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ73yMhHh+AVUWd+tWnEm39ZtbwzqfO2AHakkj3n4fptb2pthTIWuj5Tj1tTy9hAry5+QAej4w== X-Received: by 2002:a92:dcc1:0:b0:328:8770:b9c2 with SMTP id b1-20020a92dcc1000000b003288770b9c2mr507347ilr.14.1685405806881; Mon, 29 May 2023 17:16:46 -0700 (PDT) Received: from redhat.com ([38.15.36.239]) by smtp.gmail.com with ESMTPSA id d6-20020a926806000000b003248469e5easm590655ilc.43.2023.05.29.17.16.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 May 2023 17:16:46 -0700 (PDT) Date: Mon, 29 May 2023 18:16:44 -0600 From: Alex Williamson To: Jason Gunthorpe Cc: "Tian, Kevin" , "Liu, Yi L" , "joro@8bytes.org" , "robin.murphy@arm.com" , "baolu.lu@linux.intel.com" , "cohuck@redhat.com" , "eric.auger@redhat.com" , "nicolinc@nvidia.com" , "kvm@vger.kernel.org" , "mjrosato@linux.ibm.com" , "chao.p.peng@linux.intel.com" , "yi.y.sun@linux.intel.com" , "peterx@redhat.com" , "jasowang@redhat.com" , "shameerali.kolothum.thodi@huawei.com" , "lulu@redhat.com" , "suravee.suthikulpanit@amd.com" , "iommu@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "Duan, Zhenzhong" Subject: Re: [PATCH v3 00/10] Add Intel VT-d nested translation Message-ID: <20230529181644.3a6a5c7b.alex.williamson@redhat.com> In-Reply-To: References: <20230511145110.27707-1-yi.l.liu@intel.com> Organization: Red Hat Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 29 May 2023 15:43:02 -0300 Jason Gunthorpe wrote: > On Wed, May 24, 2023 at 08:59:43AM +0000, Tian, Kevin wrote: > > > At least this looks a reasonable tradeoff to some proprietary VMMs > > which never adds RO mappings in stage-2 today. > > What is the reason for the RO anyhow? > > Would it be so bad if it was DMA mapped as RW due to the errata? What if it's the zero page? Thanks, Alex