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Subject: Re: How to ensure that different peripherals getting different IOVA
 address in kernel?
To: chenfeng <puck.chen@hisilicon.com>, "joro@8bytes.org" <joro@8bytes.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "rcallicotte@gmail.com" <rcallicotte@gmail.com>,
        "jiang.liu@linux.intel.com" <jiang.liu@linux.intel.com>
References: <5600AF72.2000106@hisilicon.com> <560206AE.4020608@hisilicon.com>
Cc: Dan zhao <dan.zhao@hisilicon.com>, qijiwen <qijiwen@hisilicon.com>,
        Peter Panshilin <peter.panshilin@hisilicon.com>,
        Suzhuangluan <suzhuangluan@hisilicon.com>,
        Yiping Xu <xuyiping@hisilicon.com>,
        "Wangfei (William, Euler)" <w.f@huawei.com>
From: Robin Murphy <robin.murphy@arm.com>
Message-ID: <5602963C.8030601@arm.com>
Date: Wed, 23 Sep 2015 13:08:28 +0100
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On 23/09/15 02:55, chenfeng wrote:
> Hi all,
>
> In IOMMU architecture , how to make two different peripherals share the same page table ?
>
> In other words , is there a mechanism or structure to make two peripherals get completely different address.
>
> eg:
>
> peri-A、peri-B and peri-C share the same iova address 0-1G for some performance requests.
>
> So the A,B,C need to use the same IOVA generator to ensure this,but I don't find an architecture to make this.

This is what IOMMU domains are all about: devices in one domain are 
isolated from devices in different domains, so all you need to do is 
make sure all devices that want to share buffers are attached to the 
same domain, then they will all share that domain's IOVA space.

Robin.

>
> Any help will be appreciated.
>
> Puck
>
>