From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tetsuya Mukawa <mukawa@igel.co.jp>
Subject: Re: [PATCH v2 3/3] virtio: Add a new layer to abstract
 pci access method
Date: Mon, 1 Feb 2016 10:50:00 +0900
Message-ID: <56AEB9C8.9060703@igel.co.jp>
References: <1453108389-21006-2-git-send-email-mukawa@igel.co.jp>
 <1453973612-8599-4-git-send-email-mukawa@igel.co.jp>
 <20160129091701.GY4257@yliu-dev.sh.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Cc: dev@dpdk.org
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Return-path: <dev-bounces@dpdk.org>
Received: from mail-pf0-f182.google.com (mail-pf0-f182.google.com
 [209.85.192.182]) by dpdk.org (Postfix) with ESMTP id 559835A68
 for <dev@dpdk.org>; Mon,  1 Feb 2016 02:50:03 +0100 (CET)
Received: by mail-pf0-f182.google.com with SMTP id 65so74220879pfd.2
 for <dev@dpdk.org>; Sun, 31 Jan 2016 17:50:03 -0800 (PST)
In-Reply-To: <20160129091701.GY4257@yliu-dev.sh.intel.com>
List-Id: patches and discussions about DPDK <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>

On 2016/01/29 18:17, Yuanhan Liu wrote:
> On Thu, Jan 28, 2016 at 06:33:32PM +0900, Tetsuya Mukawa wrote:
>> This patch addss function pointers to abstract pci access method.
>> This abstraction layer will be used when virtio-net PMD supports
>> container extension.
>>
>> The below functions abstract how to access to pci configuration space.
>>
>> struct virtio_pci_cfg_ops {
>>         int   (*map)(...);
>>         void  (*unmap)(...);
>>         void *(*get_mapped_addr)(...);
>>         int   (*read)(...);
>> };
>>
>> The pci configuration space has information how to access to virtio
>> device registers. Basically, there are 2 ways to acccess to the
>> registers. One is using portio and the other is using mapped memory.
>> The below functions abstract this access method.
> One question: is there a way to map PCI memory with Qtest? I'm thinking
> if we can keep the io_read/write() for Qtest as well, if so, code could
> be simplified, a lot, IMO.
>

Yes, I agree with you.
But AFAIK, we don't have a way to mmap it from DPDK application.

We may be able to map PCI configuration space to a memory address space
that guest CPU can handle.
But even in this case, I guess we cannot access the memory without qtest
messaging.

Thanks,
Tetsuya