Re: [PATCH v3 02/18] iommu: Implement IOMMU Live update FLB callbacks

[Samiullah Khawaja]

On Fri, Jul 31, 2026 at 05:58:20AM +0000, Ankit Soni wrote:
> On Sun, Jun 14, 2026 at 11:37:12PM +0000, Samiullah Khawaja wrote:
> > Add liveupdate FLB for IOMMU state preservation. Use KHO preserve memory
> > alloc/free helper functions to allocate memory for the IOMMU Live update
> > FLB object and the serialization structs for device, domain and iommu.
> >
> > During retrieve, walk through the preserved obj array headers and
> > restore each folio. Also recreate the FLB obj.
> >
> > Signed-off-by: Samiullah Khawaja <skhawaja@xxxxxxxxxx>
> > ---
> >  MAINTAINERS                      |   9 ++
> >  drivers/iommu/Kconfig            |  12 ++
> >  drivers/iommu/Makefile           |   1 +
> >  drivers/iommu/liveupdate.c       | 212 +++++++++++++++++++++++++++++++
> >  include/linux/iommu-liveupdate.h |  18 +++
> >  include/linux/kho/abi/iommu.h    | 207 ++++++++++++++++++++++++++++++
> >  6 files changed, 459 insertions(+)
> >  create mode 100644 drivers/iommu/liveupdate.c
> >  create mode 100644 include/linux/iommu-liveupdate.h
> >  create mode 100644 include/linux/kho/abi/iommu.h
>
> ../..

[snip]

> Hi,
>
> nit, The v3 changelog has "Replace bitfields with u32 flags", but sign_extend:1
> looks like it was missed. this is 37 bytes, the only arrayed record in this
> header that isn't a multiple of 8 (iommu_device_ser is 56, iommu_hw_ser 112).
> The arrays are strided with pointer arithmetic, so the skew accumulates: from
> objects[1] onwards none of the u64s are naturally aligned.
>
> Looks like a leftover from the bitfield cleanup.

Yes, missed this one in v3. Just sent out v4, it should be cleaned up now.

Thanks,
Sami
> -Ankit