From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S932173AbbBJJqS (ORCPT <rfc822;w@1wt.eu>);
	Tue, 10 Feb 2015 04:46:18 -0500
Received: from smtp.citrix.com ([66.165.176.89]:13367 "EHLO SMTP.CITRIX.COM"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752429AbbBJJqP (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Tue, 10 Feb 2015 04:46:15 -0500
X-IronPort-AV: E=Sophos;i="5.09,549,1418083200"; 
   d="scan'208";a="224314350"
Message-ID: <54D9D363.5060904@citrix.com>
Date: Tue, 10 Feb 2015 09:46:11 +0000
From: David Vrabel <david.vrabel@citrix.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.4.0
MIME-Version: 1.0
To: "Wang, Xiaoming" <xiaoming.wang@intel.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: "linux-mips@linux-mips.org" <linux-mips@linux-mips.org>,
        "pebolle@tiscali.nl" <pebolle@tiscali.nl>,
        "Zhang, Dongxing" <dongxing.zhang@intel.com>,
        "lauraa@codeaurora.org" <lauraa@codeaurora.org>,
        "d.kasatkin@samsung.com" <d.kasatkin@samsung.com>,
        "heiko.carstens@de.ibm.com" <heiko.carstens@de.ibm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "ralf@linux-mips.org" <ralf@linux-mips.org>,
        "chris@chris-wilson.co.uk" <chris@chris-wilson.co.uk>,
        "takahiro.akashi@linaro.org" <takahiro.akashi@linaro.org>,
        "david.vrabel@citrix.com" <david.vrabel@citrix.com>,
        "linux@horizon.com" <linux@horizon.com>,
        "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
        "boris.ostrovsky@oracle.com" <boris.ostrovsky@oracle.com>,
        "Liu, Chuansheng" <chuansheng.liu@intel.com>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>
Subject: Re: [Xen-devel] [PATCH] modify the IO_TLB_SEGSIZE to io_tlb_segsize
 configurable as flexible requirement about SW-IOMMU.
References: <1423177274-22118-1-git-send-email-xiaoming.wang@intel.com>	<20150205193241.GC11646@x230.dumpdata.com> <FA47D36D6EC9FE4CB463299737C09B9901CF8CE6@shsmsx102.ccr.corp.intel.com>
In-Reply-To: <FA47D36D6EC9FE4CB463299737C09B9901CF8CE6@shsmsx102.ccr.corp.intel.com>
Content-Type: text/plain; charset="windows-1252"
Content-Transfer-Encoding: 7bit
X-DLP: MIA2
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 06/02/15 00:10, Wang, Xiaoming wrote:
> 
> 
>> -----Original Message-----
>> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com]
>> Sent: Friday, February 6, 2015 3:33 AM
>> To: Wang, Xiaoming
>> Cc: ralf@linux-mips.org; boris.ostrovsky@oracle.com;
>> david.vrabel@citrix.com; linux-mips@linux-mips.org; linux-
>> kernel@vger.kernel.org; xen-devel@lists.xenproject.org; akpm@linux-
>> foundation.org; linux@horizon.com; lauraa@codeaurora.org;
>> heiko.carstens@de.ibm.com; d.kasatkin@samsung.com;
>> takahiro.akashi@linaro.org; chris@chris-wilson.co.uk; pebolle@tiscali.nl; Liu,
>> Chuansheng; Zhang, Dongxing
>> Subject: Re: [PATCH] modify the IO_TLB_SEGSIZE to io_tlb_segsize
>> configurable as flexible requirement about SW-IOMMU.
>>
>> On Fri, Feb 06, 2015 at 07:01:14AM +0800, xiaomin1 wrote:
>>> The maximum of SW-IOMMU is limited to 2^11*128 = 256K.
>>> While in different platform and different requirements this seems improper.
>>> So modify the IO_TLB_SEGSIZE to io_tlb_segsize as configurable is make
>> sense.
>>
>> More details please. What is the issue you are hitting?
>>
> Example:
> If 1M bytes are requied. There has an error like.

Instead of allowing the bouncing of such large buffers, could the gadget
driver be modified to submit the buffers to the hardware in smaller chunks?

David