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

Message ID 20180704061349.20742-1-aik@ozlabs.ru
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Series powerpc/powernv/iommu: Optimize memory use | expand

Message

Alexey Kardashevskiy July 4, 2018, 6:13 a.m. UTC
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.



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

Comments

Alexey Kardashevskiy July 13, 2018, 5:26 a.m. UTC | #1
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