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Date:   Fri, 19 Mar 2021 14:41:32 +0100
From:   Jean-Philippe Brucker <jean-philippe@linaro.org>
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     Jacob Pan <jacob.jun.pan@linux.intel.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        David Woodhouse <dwmw2@infradead.org>,
        iommu@lists.linux-foundation.org, cgroups@vger.kernel.org,
        Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Eric Auger <eric.auger@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Raj Ashok <ashok.raj@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>,
        Wu Hao <hao.wu@intel.com>, Dave Jiang <dave.jiang@intel.com>
Subject: Re: [PATCH V4 05/18] iommu/ioasid: Redefine IOASID set and
 allocation APIs
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On Fri, Mar 19, 2021 at 09:46:45AM -0300, Jason Gunthorpe wrote:
> On Fri, Mar 19, 2021 at 10:58:41AM +0100, Jean-Philippe Brucker wrote:
> 
> > Although there is no use for it at the moment (only two upstream users and
> > it looks like amdkfd always uses current too), I quite like the
> > client-server model where the privileged process does bind() and programs
> > the hardware queue on behalf of the client process.
> 
> This creates a lot complexity, how do does process A get a secure
> reference to B? How does it access the memory in B to setup the HW?

mm_access() for example, and passing addresses via IPC

> Why do we need separation anyhow? SVM devices are supposed to be
> secure or they shouldn't do SVM.

Right

Thanks,
Jean