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Message-ID: <f1dbfb6a-5a53-f440-5d3a-25772c67547f@linux.intel.com>
Date:   Fri, 11 Aug 2023 09:53:41 +0800
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Cc:     baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
        Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Nicolin Chen <nicolinc@nvidia.com>,
        "Liu, Yi L" <yi.l.liu@intel.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>,
        "iommu@lists.linux.dev" <iommu@lists.linux.dev>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 08/12] iommu: Prepare for separating SVA and IOPF
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To:     Jason Gunthorpe <jgg@ziepe.ca>,
        "Tian, Kevin" <kevin.tian@intel.com>
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From:   Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <ZNUUjXMrLyU3g5KM@ziepe.ca>
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On 2023/8/11 0:47, Jason Gunthorpe wrote:
> On Thu, Aug 10, 2023 at 02:35:40AM +0000, Tian, Kevin wrote:
>>> From: Baolu Lu<baolu.lu@linux.intel.com>
>>> Sent: Wednesday, August 9, 2023 6:41 PM
>>>
>>> On 2023/8/9 8:02, Tian, Kevin wrote:
>>>>> From: Jason Gunthorpe<jgg@ziepe.ca>
>>>>> Sent: Wednesday, August 9, 2023 2:43 AM
>>>>>
>>>>> On Thu, Aug 03, 2023 at 08:16:47AM +0000, Tian, Kevin wrote:
>>>>>
>>>>>> Is there plan to introduce further error in the future? otherwise this
>>> should
>>>>>> be void.
>>>>>>
>>>>>> btw the work queue is only for sva. If there is no other caller this can be
>>>>>> just kept in iommu-sva.c. No need to create a helper.
>>>>> I think more than just SVA will need a work queue context to process
>>>>> their faults.
>>>>>
>>>> then this series needs more work. Currently the abstraction doesn't
>>>> include workqueue in the common fault reporting layer.
>>> Do you mind elaborate a bit here? workqueue is a basic infrastructure in
>>> the fault handling framework, but it lets the consumers choose to use
>>> it, or not to.
>>>
>> My understanding of Jason's comment was to make the workqueue the
>> default path instead of being opted by the consumer.. that is my 1st
>> impression but might be wrong...
> Yeah, that is one path. Do we have anyone that uses this that doesn't
> want the WQ? (actually who even uses this besides SVA?)

I am still confused. When we forward iopf's to user space through the
iommufd, we don't need to schedule a WQ, right? Or I misunderstood here?

Best regards,
baolu