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Date:   Tue, 22 Mar 2022 10:02:41 +0000
From:   Jean-Philippe Brucker <jean-philippe@linaro.org>
To:     Lu Baolu <baolu.lu@linux.intel.com>
Cc:     Jason Gunthorpe <jgg@nvidia.com>,
        "Tian, Kevin" <kevin.tian@intel.com>,
        Joerg Roedel <joro@8bytes.org>,
        Christoph Hellwig <hch@infradead.org>,
        "Raj, Ashok" <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        Eric Auger <eric.auger@redhat.com>,
        "Liu, Yi L" <yi.l.liu@intel.com>,
        "Pan, Jacob jun" <jacob.jun.pan@intel.com>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC 10/11] iommu: Make IOPF handling framework generic
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On Tue, Mar 22, 2022 at 01:03:14PM +0800, Lu Baolu wrote:
> On 2022/3/21 20:43, Jason Gunthorpe wrote:
> > On Mon, Mar 21, 2022 at 11:42:16AM +0000, Jean-Philippe Brucker wrote:
> > 
> > > I tend to disagree with that last part. The fault is caused by a specific
> > > device accessing shared page tables. We should keep that device
> > > information throughout the fault handling, so that we can report it to the
> > > driver when things go wrong.
> > SVA faults should never be reported to drivers??
> > 
> 
> When things go wrong, the corresponding response code will be responded
> to the device through iommu_page_response(). The hardware should then
> report the failure to the device driver and the device driver will
> handle it in the device-specific way. There's no need to propagate the
> I/O page faults to the device driver in any case. Do I understand it
> right?

In theory yes, but devices don't necessarily have the ability to report
precise errors, we may have more information.

Thanks,
Jean