On 5/5/22 08:25, Shameerali Kolothum Thodi wrote: >> -----Original Message----- >> From: Joao Martins [mailto:joao.m.martins@xxxxxxxxxx] >> Sent: 29 April 2022 12:05 >> To: Tian, Kevin <kevin.tian@xxxxxxxxx> >> Cc: Joerg Roedel <joro@xxxxxxxxxx>; Suravee Suthikulpanit >> <suravee.suthikulpanit@xxxxxxx>; Will Deacon <will@xxxxxxxxxx>; Robin >> Murphy <robin.murphy@xxxxxxx>; Jean-Philippe Brucker >> <jean-philippe@xxxxxxxxxx>; zhukeqian <zhukeqian1@xxxxxxxxxx>; >> Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>; >> David Woodhouse <dwmw2@xxxxxxxxxxxxx>; Lu Baolu >> <baolu.lu@xxxxxxxxxxxxxxx>; Jason Gunthorpe <jgg@xxxxxxxxxx>; Nicolin Chen >> <nicolinc@xxxxxxxxxx>; Yishai Hadas <yishaih@xxxxxxxxxx>; Eric Auger >> <eric.auger@xxxxxxxxxx>; Liu, Yi L <yi.l.liu@xxxxxxxxx>; Alex Williamson >> <alex.williamson@xxxxxxxxxx>; Cornelia Huck <cohuck@xxxxxxxxxx>; >> kvm@xxxxxxxxxxxxxxx; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx >> Subject: Re: [PATCH RFC 15/19] iommu/arm-smmu-v3: Add >> set_dirty_tracking_range() support >> >> On 4/29/22 09:28, Tian, Kevin wrote: >>>> From: Joao Martins <joao.m.martins@xxxxxxxxxx> >>>> Sent: Friday, April 29, 2022 5:09 AM >>>> >>>> Similar to .read_and_clear_dirty() use the page table >>>> walker helper functions and set DBM|RDONLY bit, thus >>>> switching the IOPTE to writeable-clean. >>> >>> this should not be one-off if the operation needs to be >>> applied to IOPTE. Say a map request comes right after >>> set_dirty_tracking() is called. If it's agreed to remove >>> the range op then smmu driver should record the tracking >>> status internally and then apply the modifier to all the new >>> mappings automatically before dirty tracking is disabled. >>> Otherwise the same logic needs to be kept in iommufd to >>> call set_dirty_tracking_range() explicitly for every new >>> iopt_area created within the tracking window. >> >> Gah, I totally missed that by mistake. New mappings aren't >> carrying over the "DBM is set". This needs a new io-pgtable >> quirk added post dirty-tracking toggling. >> >> I can adjust, but I am at odds on including this in a future >> iteration given that I can't really test any of this stuff. >> Might drop the driver until I have hardware/emulation I can >> use (or maybe others can take over this). It was included >> for revising the iommu core ops and whether iommufd was >> affected by it. > > [+Kunkun Jiang]. I think he is now looking into this and might have > a test setup to verify this. I'll keep him CC'ed next iterations. Thanks! FWIW, the should change a bit on next iteration (simpler) by always enabling DBM from the start. SMMUv3 ::set_dirty_tracking() becomes a simpler function that tests quirks (i.e. DBM set) and what not, and calls read_and_clear_dirty() without a bitmap argument to clear dirties.
