Re: [PATCH kernel v3 0/6] powerpc/powernv/iommu: Optimize memory use

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On Wed,  4 Jul 2018 16:13:43 +1000
Alexey Kardashevskiy <aik@ozlabs.ru> wrote:

> This patchset aims to reduce actual memory use for guests with
> sparse memory. The pseries guest uses dynamic DMA windows to map
> the entire guest RAM but it only actually maps onlined memory
> which may be not be contiguous. I hit this when tried passing
> through NVLink2-connected GPU RAM of NVIDIA V100 and trying to
> map this RAM at the same offset as in the real hardware
> forced me to rework I handle these windows.
> 
> This moves userspace-to-host-physical translation table
> (iommu_table::it_userspace) from VFIO TCE IOMMU subdriver to
> the platform code and reuses the already existing multilevel
> TCE table code which we have for the hardware tables.
> At last in 6/6 I switch to on-demand allocation so we do not
> allocate huge chunks of the table if we do not have to;
> there is some math in 6/6.
> 
> Changes:
> v3:
> * rebased on v4.18-rc3 and fixed compile error in 6/6
> 
> v2:
> * bugfix and error handling in 6/6
> 
> 
> This is based on sha1
> 021c917 Linus Torvalds "Linux 4.18-rc3".
> 
> Please comment. Thanks.


Ping?

> 
> 
> 
> Alexey Kardashevskiy (6):
>   powerpc/powernv: Remove useless wrapper
>   powerpc/powernv: Move TCE manupulation code to its own file
>   KVM: PPC: Make iommu_table::it_userspace big endian
>   powerpc/powernv: Add indirect levels to it_userspace
>   powerpc/powernv: Rework TCE level allocation
>   powerpc/powernv/ioda: Allocate indirect TCE levels on demand
> 
>  arch/powerpc/platforms/powernv/Makefile       |   2 +-
>  arch/powerpc/include/asm/iommu.h              |  11 +-
>  arch/powerpc/platforms/powernv/pci.h          |  44 ++-
>  arch/powerpc/kvm/book3s_64_vio.c              |  11 +-
>  arch/powerpc/kvm/book3s_64_vio_hv.c           |  18 +-
>  arch/powerpc/platforms/powernv/pci-ioda-tce.c | 399 ++++++++++++++++++++++++++
>  arch/powerpc/platforms/powernv/pci-ioda.c     | 184 ++----------
>  arch/powerpc/platforms/powernv/pci.c          | 158 ----------
>  drivers/vfio/vfio_iommu_spapr_tce.c           |  65 +----
>  9 files changed, 478 insertions(+), 414 deletions(-)
>  create mode 100644 arch/powerpc/platforms/powernv/pci-ioda-tce.c



--
Alexey