Re: S390 testing for IOMMUFD

[Anthony Krowiak <akrowiak@linux.ibm.com>]

On 11/8/22 5:12 AM, Christian Borntraeger wrote:
>
>
> Am 08.11.22 um 02:09 schrieb Jason Gunthorpe:
>> On Mon, Nov 07, 2022 at 08:48:53PM -0400, Jason Gunthorpe wrote:
>>> [
>>> This has been in linux-next for a little while now, and we've completed
>>> the syzkaller run. 1300 hours of CPU time have been invested since the
>>> last report with no improvement in coverage or new detections. 
>>> syzkaller
>>> coverage reached 69%(75%), and review of the misses show substantial
>>> amounts are WARN_ON's and other debugging which are not expected to be
>>> covered.
>>> ]
>>>
>>> iommufd is the user API to control the IOMMU subsystem as it relates to
>>> managing IO page tables that point at user space memory.
>>
>> [chop cc list]
>>
>> s390 mdev maintainers,
>>
>> Can I ask your help to test this with the two S390 mdev drivers? Now
>> that gvt is passing and we've covered alot of the QA ground it is a
>> good time to run it.
>>
>> Take the branch from here:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd.git/log/?h=for-next 
>>
>
>>
>> And build the kernel with
>>
>> CONFIG_VFIO_CONTAINER=n
>> CONFIG_IOMMUFD=y
>> CONFIG_IOMMUFD_VFIO_CONTAINER=y
>>
>> And your existing stuff should work with iommufd providing the iommu
>> support to vfio. There will be a dmesg confirming this.
>
> Gave it a quick spin with vfio_ap:
> [  401.679199] vfio_ap_mdev b01a7c33-9696-48b2-9a98-050e8e17c69a: 
> Adding to iommu group 1
> [  402.085386] iommufd: IOMMUFD is providing /dev/vfio/vfio, not VFIO.
>
> Some tests seem to work, but others dont (running into timeouts). I 
> need to look
> into that (or ideally Tony will have a look, FWIW 
> tests.test_vfio_ap.VfioAPAssignMdevToGuestTest
> fails for me.


I'm looking into it.


>
>
> The same kernel tree with defconfig (instead of 
> CONFIG_IOMMUFD_VFIO_CONTAINER=y) works fine.
>>
>> Let me know if there are any problems!
>>
>> If I recall there was some desire from the S390 platform team to start
>> building on iommufd to create some vIOMMU acceleration for S390
>> guests, this is a necessary first step.
>>
>> Thanks,
>> Jason