Re: [PATCH v11 00/13] SMMUv3 Nested Stage Setup (IOMMU part)

[Auger Eric <eric.auger@redhat.com>]

Hi Shameer,

On 5/7/20 8:59 AM, Shameerali Kolothum Thodi wrote:
> Hi Eric,
> 
>> -----Original Message-----
>> From: Shameerali Kolothum Thodi
>> Sent: 30 April 2020 10:38
>> To: 'Auger Eric' <eric.auger@redhat.com>; Zhangfei Gao
>> <zhangfei.gao@linaro.org>; eric.auger.pro@gmail.com;
>> iommu@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
>> kvm@vger.kernel.org; kvmarm@lists.cs.columbia.edu; will@kernel.org;
>> joro@8bytes.org; maz@kernel.org; robin.murphy@arm.com
>> Cc: jean-philippe@linaro.org; alex.williamson@redhat.com;
>> jacob.jun.pan@linux.intel.com; yi.l.liu@intel.com; peter.maydell@linaro.org;
>> tn@semihalf.com; bbhushan2@marvell.com
>> Subject: RE: [PATCH v11 00/13] SMMUv3 Nested Stage Setup (IOMMU part)
>>
>> Hi Eric,
>>
>>> -----Original Message-----
>>> From: Auger Eric [mailto:eric.auger@redhat.com]
>>> Sent: 16 April 2020 08:45
>>> To: Zhangfei Gao <zhangfei.gao@linaro.org>; eric.auger.pro@gmail.com;
>>> iommu@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
>>> kvm@vger.kernel.org; kvmarm@lists.cs.columbia.edu; will@kernel.org;
>>> joro@8bytes.org; maz@kernel.org; robin.murphy@arm.com
>>> Cc: jean-philippe@linaro.org; Shameerali Kolothum Thodi
>>> <shameerali.kolothum.thodi@huawei.com>; alex.williamson@redhat.com;
>>> jacob.jun.pan@linux.intel.com; yi.l.liu@intel.com; peter.maydell@linaro.org;
>>> tn@semihalf.com; bbhushan2@marvell.com
>>> Subject: Re: [PATCH v11 00/13] SMMUv3 Nested Stage Setup (IOMMU part)
>>>
>>> Hi Zhangfei,
>>>
>>> On 4/16/20 6:25 AM, Zhangfei Gao wrote:
>>>>
>>>>
>>>> On 2020/4/14 下午11:05, Eric Auger wrote:
>>>>> This version fixes an issue observed by Shameer on an SMMU 3.2,
>>>>> when moving from dual stage config to stage 1 only config.
>>>>> The 2 high 64b of the STE now get reset. Otherwise, leaving the
>>>>> S2TTB set may cause a C_BAD_STE error.
>>>>>
>>>>> This series can be found at:
>>>>> https://github.com/eauger/linux/tree/v5.6-2stage-v11_10.1
>>>>> (including the VFIO part)
>>>>> The QEMU fellow series still can be found at:
>>>>> https://github.com/eauger/qemu/tree/v4.2.0-2stage-rfcv6
>>>>>
>>>>> Users have expressed interest in that work and tested v9/v10:
>>>>> - https://patchwork.kernel.org/cover/11039995/#23012381
>>>>> - https://patchwork.kernel.org/cover/11039995/#23197235
>>>>>
>>>>> Background:
>>>>>
>>>>> This series brings the IOMMU part of HW nested paging support
>>>>> in the SMMUv3. The VFIO part is submitted separately.
>>>>>
>>>>> The IOMMU API is extended to support 2 new API functionalities:
>>>>> 1) pass the guest stage 1 configuration
>>>>> 2) pass stage 1 MSI bindings
>>>>>
>>>>> Then those capabilities gets implemented in the SMMUv3 driver.
>>>>>
>>>>> The virtualizer passes information through the VFIO user API
>>>>> which cascades them to the iommu subsystem. This allows the guest
>>>>> to own stage 1 tables and context descriptors (so-called PASID
>>>>> table) while the host owns stage 2 tables and main configuration
>>>>> structures (STE).
>>>>>
>>>>>
>>>>
>>>> Thanks Eric
>>>>
>>>> Tested v11 on Hisilicon kunpeng920 board via hardware zip accelerator.
>>>> 1. no-sva works, where guest app directly use physical address via ioctl.
>>> Thank you for the testing. Glad it works for you.
>>>> 2. vSVA still not work, same as v10,
>>> Yes that's normal this series is not meant to support vSVM at this stage.
>>>
>>> I intend to add the missing pieces during the next weeks.
>>
>> Thanks for that. I have made an attempt to add the vSVA based on
>> your v10 + JPBs sva patches. The host kernel and Qemu changes can
>> be found here[1][2].
>>
>> This basically adds multiple pasid support on top of your changes.
>> I have done some basic sanity testing and we have some initial success
>> with the zip vf dev on our D06 platform. Please note that the STALL event is
>> not yet supported though, but works fine if we mlock() guest usr mem.
> 
> I have added STALL support for our vSVA prototype and it seems to be
> working(on our hardware). I have updated the kernel and qemu branches with
> the same[1][2]. I should warn you though that these are prototype code and I am pretty
> much re-using the VFIO_IOMMU_SET_PASID_TABLE interface for almost everything.
> But thought of sharing, in case if it is useful somehow!.

Thank you very much for your work. I intend to look at your additions by
beginning of next week.

Best Regards

Eric
> 
> Thanks,
> Shameer
> 
> [1]https://github.com/hisilicon/kernel-dev/commits/vsva-prototype-host-v1
> 
> [2]https://github.com/hisilicon/qemu/tree/v4.2.0-2stage-rfcv6-vsva-prototype-v1
> 

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