[v4,0/5] s390x/pci: Accomodate vfio DMA limiting

Message

Matthew Rosato Sept. 17, 2020, 2:20 p.m. UTC

Kernel commit 492855939bdb added a limit to the number of outstanding DMA
requests for a type1 vfio container.  However, lazy unmapping in s390 can 
in fact cause quite a large number of outstanding DMA requests to build up
prior to being purged, potentially the entire guest DMA space.  This
results in unexpected 'VFIO_MAP_DMA failed: No space left on device'
conditions seen in QEMU.

This patchset adds support to qemu to retrieve the number of allowable DMA
requests via the VFIO_IOMMU_GET_INFO ioctl.  The patches are separated into
vfio hits which add support for reading in VFIO_IOMMU_GET_INFO capability
chains and getting the per-container dma_avail value, and s390 hits to 
track DMA usage on a per-container basis.

Associated kernel patch:
https://marc.info/?l=kvm&m=160019703922812&w=2


Changes from v3:
- Patch 2,3: Added RBs provided (thank you!)
- Patch 4: retry the ioctl in the same manner as vfio_get_region_info
- Patch 5: switch to static inline functions
- Patch 5: relocate more code to s390-pci-vfio.*


Matthew Rosato (5):
  linux-headers: update against 5.9-rc5
  vfio: Create shared routine for scanning info capabilities
  vfio: Find DMA available capability
  s390x/pci: Add routine to get the vfio dma available count
  s390x/pci: Honor DMA limits set by vfio

 hw/s390x/meson.build                               |   1 +
 hw/s390x/s390-pci-bus.c                            |  16 ++-
 hw/s390x/s390-pci-bus.h                            |   9 ++
 hw/s390x/s390-pci-inst.c                           |  45 ++++++-
 hw/s390x/s390-pci-inst.h                           |   3 +
 hw/s390x/s390-pci-vfio.c                           |  96 ++++++++++++++
 hw/s390x/s390-pci-vfio.h                           |  22 ++++
 hw/vfio/common.c                                   |  52 ++++++--
 include/hw/vfio/vfio-common.h                      |   2 +
 include/standard-headers/drm/drm_fourcc.h          | 140 +++++++++++++++++++++
 include/standard-headers/linux/ethtool.h           |  87 +++++++++++++
 include/standard-headers/linux/input-event-codes.h |   3 +-
 include/standard-headers/linux/vhost_types.h       |  11 ++
 include/standard-headers/linux/virtio_9p.h         |   4 +-
 include/standard-headers/linux/virtio_blk.h        |  26 ++--
 include/standard-headers/linux/virtio_config.h     |   8 +-
 include/standard-headers/linux/virtio_console.h    |   8 +-
 include/standard-headers/linux/virtio_net.h        |   6 +-
 include/standard-headers/linux/virtio_scsi.h       |  20 +--
 linux-headers/asm-generic/unistd.h                 |   6 +-
 linux-headers/asm-mips/unistd_n32.h                |   1 +
 linux-headers/asm-mips/unistd_n64.h                |   1 +
 linux-headers/asm-mips/unistd_o32.h                |   1 +
 linux-headers/asm-powerpc/kvm.h                    |   5 +
 linux-headers/asm-powerpc/unistd_32.h              |   1 +
 linux-headers/asm-powerpc/unistd_64.h              |   1 +
 linux-headers/asm-s390/kvm.h                       |   7 +-
 linux-headers/asm-s390/unistd_32.h                 |   1 +
 linux-headers/asm-s390/unistd_64.h                 |   1 +
 linux-headers/asm-x86/unistd_32.h                  |   1 +
 linux-headers/asm-x86/unistd_64.h                  |   1 +
 linux-headers/asm-x86/unistd_x32.h                 |   1 +
 linux-headers/linux/kvm.h                          |  10 +-
 linux-headers/linux/vfio.h                         |  17 ++-
 linux-headers/linux/vhost.h                        |   2 +
 35 files changed, 554 insertions(+), 62 deletions(-)
 create mode 100644 hw/s390x/s390-pci-vfio.c
 create mode 100644 hw/s390x/s390-pci-vfio.h

Comments

[e-mail] Sept. 17, 2020, 2:46 p.m. UTC | #1

Patchew URL: https://patchew.org/QEMU/[e-mail]/



Hi,

This series failed the docker-quick@centos7 build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.






The full log is available at
http://patchew.org/logs/[e-mail]/testing.docker-quick@centos7/?type=message.
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Matthew Rosato Sept. 17, 2020, 3:05 p.m. UTC | #2

On 9/17/20 10:46 AM, [e-mail] wrote:
> Patchew URL: https://patchew.org/QEMU/[e-mail]/
> 
> 
> 
> Hi,
> 
> This series failed the docker-quick@centos7 build test. Please find the testing commands and
> their output below. If you have Docker installed, you can probably reproduce it
> locally.
> 
> 

Errors seem to be of the flavor

'N/A. Internal error while reading log file'
and
'No space left on device'

seems like a patchew disk issue rather than something with this patchset?

> 
> 
> 
> 
> The full log is available at
> http://patchew.org/logs/[e-mail]/testing.docker-quick@centos7/?type=message.
> ---
> Email generated automatically by Patchew [https://patchew.org/].
> Please send your feedback to [e-mail]
>