Re: [PATCH 1/2] vfio/ap: Don't initialize HOST_IOMMU_DEVICE with mdev

[Joao Martins]

On 22/07/2024 16:46, Anthony Krowiak wrote:
> 
> On 7/22/24 5:18 AM, Joao Martins wrote:
>> On 22/07/2024 08:07, Zhenzhong Duan wrote:
>>> mdevs aren't "physical" devices and when asking for backing IOMMU info,
>>> it fails the entire provisioning of the guest. Fix that by setting
>>> vbasedev->mdev true so skipping HostIOMMUDevice initialization in the
>>> presence of mdevs.
>>>
>>> Fixes: 930589520128 ("vfio/iommufd: Implement 
>>> HostIOMMUDeviceClass::realize()
>>> handler")
>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> 
> 
> I'm at a bit of a loss here. We've been starting guests with AP devices being
> passed through using VFIO for years. Did the fix for
> 
> 930589520128 precipitate this?

Yes. The fix commit ids introduced this and it was not intended. Also the
failure, again, is only reproduceable with IOMMUFD and it doesn't apply for
type1-iommu that you are likely using. Both are different IOMMU backends.

        Joao