Re: [PATCH v6 0/9] hw/iommufd: IOMMUFD Dirty Tracking

[Joao Martins]

On 23/07/2024 15:23, Yi Liu wrote:
> On 2024/7/23 05:13, Joao Martins wrote:
>> This small series adds support for IOMMU dirty tracking support via the
>> IOMMUFD backend. The hardware capability is available on most recent x86
>> hardware (and these SMMUv3 in upcoming v6.11). The series is divided
>> organized as follows:
>>
>> * Patches 1 - 7: IOMMUFD backend support for dirty tracking;
>>
>> Introduce auto domains -- Patch 3 goes into more detail, but the gist is that
>> we will find and attach a device to a compatible IOMMU domain, or allocate a 
>> new
>> hardware pagetable *or* rely on kernel IOAS attach (for mdevs). Afterwards 
>> 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 always request the HWPT for
>> dirty tracking if supported, or rely on device dirty page tracking. This
>> is a little simplistic and we aren't necessarily utilizing IOMMU dirty
>> tracking even if we ask during hwpt allocation.
>>
>> 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 8 - 9: Don't block live migration where there's no VF dirty
>> tracker, considering that we have IOMMU dirty tracking.
>>
>> Comments and feedback appreciated (on patches 1, 5, 8, 9)
> 
> Hi Joao,
> 
> Do you have a github branch for this version? :)
> 

No, but you can probably use Cedric's vfio-next branch:

        https://github.com/legoater/qemu/tree/vfio-next

... Given that he has just submitted his PR with this series.

        Joao