mbox series

[v2,0/5] iommu/s390: Further improvements

Message ID 20221109142903.4080275-1-schnelle@linux.ibm.com
Headers
Series iommu/s390: Further improvements |

Message

Niklas Schnelle Nov. 9, 2022, 2:28 p.m. UTC 
  Hi All,

This series of patches improves the s390 IOMMU driver. These improvements help
existing IOMMU users, mainly vfio-pci, but at the same time are also in
preparation of converting s390 to use the common DMA API implementation in
drivers/iommu/dma-iommu.c instead of its platform specific DMA API in
arch/s390/pci/pci_dma.c that sidesteps the IOMMU driver to control the same
hardware interface directly.

Among the included changes patch 1 improves the robustness of switching IOMMU
domains and patch 2 adds the I/O TLB operations necessary for the DMA API
conversion. Patches 3, 4, and 5 aim to improve performance with patch 5 being
the most intrusive by removing the I/O translation table lock and using atomic
updates instead.

This series is based on the s390 branch of Joerg's IOMMU tree[0] that includes
the latest s390 IOMMU fixes. It is available for easy testing in the
iommu_improve_v2 branch with signed tag s390_iommu_improve_v2 of my
git.kernel.org tree[1].

Best regards,
Niklas Schnelle

Changes sinve v1:
- If an IOTLB flush fails for one device don't skip the flush for other devices.
  This is also needed when RCU readers try to flush a detached device. (Jason)
- Free a domain's IOMMU translation table via call_rcu() (Jason)

[0] https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/log/?h=s390
[1] https://git.kernel.org/pub/scm/linux/kernel/git/niks/linux.git/

Niklas Schnelle (5):
  iommu/s390: Make attach succeed even if the device is in error state
  iommu/s390: Add I/O TLB ops
  iommu/s390: Use RCU to allow concurrent domain_list iteration
  iommu/s390: Optimize IOMMU table walking
  s390/pci: use lock-free I/O translation updates

 arch/s390/include/asm/pci.h |   4 +-
 arch/s390/kvm/pci.c         |   6 +-
 arch/s390/pci/pci.c         |  13 +--
 arch/s390/pci/pci_dma.c     |  77 +++++++++------
 drivers/iommu/s390-iommu.c  | 184 ++++++++++++++++++++++++------------
 5 files changed, 185 insertions(+), 99 deletions(-)

Comments

Joerg Roedel Nov. 19, 2022, 9:28 a.m. UTC | #1 
On Wed, Nov 09, 2022 at 03:28:58PM +0100, Niklas Schnelle wrote:
> Niklas Schnelle (5):
>   iommu/s390: Make attach succeed even if the device is in error state
>   iommu/s390: Add I/O TLB ops
>   iommu/s390: Use RCU to allow concurrent domain_list iteration
>   iommu/s390: Optimize IOMMU table walking
>   s390/pci: use lock-free I/O translation updates

Applied, thanks.