On 14/02/2024 15:40, Cédric Le Goater wrote:
> Hello Joao,
>
> On 2/13/24 12:59, Joao Martins wrote:
>> On 12/02/2024 13:56, Joao Martins wrote:
>>> This small series adds support for Dirty Tracking in IOMMUFD backend.
>>> The sole reason I still made it RFC is because of the second patch,
>>> where we are implementing user-managed auto domains.
>>>
>>> In essence it is quite similar to the original IOMMUFD series where we
>>> would allocate a HWPT, until we switched later on into a IOAS attach.
>>> Patch 2 goes into more detail, but the gist is that there's two modes of
>>> using IOMMUFD and by keep using kernel managed auto domains we would end
>>> up duplicating the same flags we have in HWPT but into the VFIO IOAS
>>> attach. While it is true that just adding a flag is simpler, it also
>>> creates duplication and motivates duplicate what hwpt-alloc already has.
>>> But there's a chance I have the wrong expectation here, so any feedback
>>> welcome.
>>>
>>> The series is divided into:
>>>
>>> * Patch 1: Adds a simple helper to get device capabilities;
>>>
>>> * Patches 2 - 5: IOMMUFD backend support for dirty tracking;
>>>
>>> The workflow is relatively simple:
>>>
>>> 1) Probe device and allow dirty tracking in the HWPT
>>> 2) Toggling dirty tracking on/off
>>> 3) Read-and-clear of Dirty IOVAs
>>>
>>> The heuristics selected for (1) were to enable it *if* device supports
>>> migration but doesn't support VF dirty tracking or IOMMU dirty tracking
>>> is supported. The latter is for the hotplug case where we can add a device
>>> without a tracker and thus still support migration.
>>>
>>> The unmap case is deferred until further vIOMMU support with migration
>>> is added[3] which will then introduce the usage of
>>> IOMMU_HWPT_GET_DIRTY_BITMAP_NO_CLEAR in GET_DIRTY_BITMAP ioctl in the
>>> dma unmap bitmap flow.
>>>
>>> * Patches 6-8: Add disabling of hugepages to allow tracking at base
>>> page; avoid blocking live migration where there's no VF dirty
>>> tracker, considering that we have IOMMU dirty tracking. And allow
>>> disabling VF dirty tracker via qemu command line.
>>>
>>> This series builds on top of Zhengzhong series[0], but only requires the
>>> first 9 patches i.e. up to ("vfio/pci: Initialize host iommu device
>>> instance after attachment")[1] that are more generic IOMMUFD device
>>> plumbing, and doesn't require the nesting counterpart.
>>>
>> I need to add that this series doesn't *need* to be based on Zhengzhong
>> series.
>> Though given that he is consolidating how an IOMMUFD device info is
>> represented
>> it felt the correct thing to do. For dirty tracking we mainly need the
>> dev_id/iommufd available when we are going to attach, that's it.
>>
>> I've pushed this series version that doesn't have such dependency, let me
>> know
>> if you want me to pursue this version instead going forward:
>>
>> https://github.com/jpemartins/qemu/commits/iommufd-v5.nodeps
>
> I feel I have lost track of all the different patchsets.
>
> To recap, there is yours :
>
> * vfio/iommufd: IOMMUFD Dirty Tracking
>
> https://lore.kernel.org/qemu-devel/20240212135643.5858-1-joao.m.mart...@oracle.com/
>
> Zhengzhong's :
>
> * [PATCH rfcv2 00/18] Check and sync host IOMMU cap/ecap with vIOMMU
>
> https://lore.kernel.org/qemu-devel/20240201072818.327930-1-zhenzhong.d...@intel.com/
>
There's also this one from Zhenzhong which depends on this set above:
https://lore.kernel.org/qemu-devel/20240115103735.132209-1-zhenzhong.d...@intel.com/
But I suspect that part of it is stale already, considering a whole lot of
IOMMUFDDevice was reworked. Though the series is about bringup intel-iommu
nesting support.
> Eric's :
>
> * [RFC 0/7] VIRTIO-IOMMU/VFIO: Fix host iommu geometry handling for hotplugged
> devices
>
> https://lore.kernel.org/qemu-devel/20240117080414.316890-1-eric.au...@redhat.com/
>
> Steve's:
>
> * [PATCH V3 00/13] allow cpr-reboot for vfio
>
> https://lore.kernel.org/qemu-devel/1707418446-134863-1-git-send-email-steven.sist...@oracle.com/
>
> Mine, which should be an RFC :
>
> * [PATCH 00/14] migration: Improve error reporting
> https://lore.kernel.org/qemu-devel/20240207133347.1115903-1-...@redhat.com/
>
> Anything else ?
In terms of major series, I think you only forgot one. The rest look to be
what's out there.
Just to avoid confusion, yesterday's message was just providing an alternative
of this same series but it that wouldn't be dependent on:
[PATCH rfcv2 00/18] Check and sync host IOMMU cap/ecap with vIOMMU
... which is what is posted in this link:
https://github.com/jpemartins/qemu/commits/iommufd-v5.nodeps
While the series, as posted, is here:
https://github.com/jpemartins/qemu/commits/iommufd-v5
