From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [PATCH v4 02/15] mem: introduce IOVA type
Date: Mon, 06 Nov 2017 09:37:27 +0100
Message-ID: <3304743.b7VfCBXbgQ@xps>
References: <20170814151537.29454-1-santosh.shukla@caviumnetworks.com>
 <20171106014141.13266-3-thomas@monjalon.net>
 <80cb9e8f-c493-4b5f-909f-9ae233ba6541@caviumnetworks.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7Bit
Cc: olivier.matz@6wind.com, sergio.gonzalez.monroy@intel.com,
 anatoly.burakov@intel.com, dev@dpdk.org
To: santosh <santosh.shukla@caviumnetworks.com>
Return-path: <dev-bounces@dpdk.org>
Received: from out4-smtp.messagingengine.com (out4-smtp.messagingengine.com
 [66.111.4.28]) by dpdk.org (Postfix) with ESMTP id 757B51B223
 for <dev@dpdk.org>; Mon,  6 Nov 2017 09:37:30 +0100 (CET)
In-Reply-To: <80cb9e8f-c493-4b5f-909f-9ae233ba6541@caviumnetworks.com>
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

06/11/2017 06:38, santosh:
> 
> On Monday 06 November 2017 07:11 AM, Thomas Monjalon wrote:
> > The IO virtual addresses may be used instead of physical addresses.
> > As IOVA is more generic, it should be used in most places instead
> > of physical address wording.
> >
> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> > ---
> > +/**
> > + * IO virtual address type.
> > + * When the physical addressing mode is in use,
> > + * the translation from a virtual address to a physical address
> > + * is a direct mapping, i.e. the same value.
> > + */
> 
> I guess - that description applicable for iova=va mode
> and for iova=pa mode - Need to do explicit virt2phy translation.
> I believe you mis-wrote - s/physical addressing mode/virtual addressing mode.

Not sure to understand your comment.
Let me reword the description to be less ambiguous:

* When the physical addressing mode (IOVA as PA) is in use,
* the translation from an IO virtual address (IOVA) to a physical address
* is a direct mapping, i.e. the same value.
* Otherwise, in virtual mode (IOVA as VA), an IOMMU may do the translation.

Is this description correct?